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Global climate change, its impact on stable food production in the future and possibilities to overcome the problem are the major priorities for research. Breeding varieties with increase adaptability to changing environments, together with better tolerance/resistance to abiotic stress, pest and diseases are possible solution. Maize is one of the most important crops, with high grain yield reduction induced by drought stress. In the present study twenty-six maize landraces from drought tolerant mini-core collection were tested under optimal, drought, and a combination of drought and high density stresses in the field. Morphological traits, plant height, total number of leaves, leaf length, leaf width, anthesis-silking interval and grain yield were recorded for each entry in two replications in three experiments. Besides, drought tolerant indices were evaluated to test the ability to separate more drought tolerant accessions from those with less stress tolerance. Five stress tolerance indices, including stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), stress susceptibility (SSI), and stress tolerance (TOL) were calculated. Data analyses revealed that STI, MP and GMP had positive and significant correlations with grain yield under all conditions. Three-dimensional diagrams displayed assignment of landraces L25, L1, L14, L3, L26, L15 and L16 to group A, based on the stress tolerance index and achieved grain yield under optimal, drought stress, and a combination of drought and high density stress. A biplot analysis efficiently separated groups of landraces with different level of drought tolerance and grain yield. Based on all obtained results, maize landraces L25, L14, L1 and L3, as the most valuable source of drought tolerance, could be recommended for further use in breeding programs.

Drought is one of the most serious a biotic factors limiting crop production worldwide. Prediction of climate change increases the need of better adaptation and breeding for improved drought tolerance in crops. Maize is one of the most sensitive crops to drought, despite of the fact that it is a C4 plant, with high photosynthetic rate and relatively low transpiration rate. In Serbia drought severely decreased maize grain yield, particularly in the last decade. A major task for breeders is to create drought tolerant maize that will successfully cope with negative consequences of global warming are facing scientists today. Enhancing the tolerance of maize has been elusive in terms of conventional plant breeding. Interdisciplinary approaches tried to understand and dissect the mechanism of drought tolerance, but with limited success. Modern genomics and genetics, together with advances in phenotyping and knowledge in physiology and breeding are expected to reveal genes and pathways that confer drought tolerance., Suša je jedan od najznačajnijih abiotičkih faktora koji ograničava biljnu proizvodnju širom sveta. Projekcije klimatskih promena povećavaju potrebu za boljom adaptacijom useva i oplemenjivanjem na poboljšanu tolerantnost prema suši. Kukuruz je jedan od najosetljivijih useva na sušu, uprkos činjenici da je C4 biljka, sa visokom brzinom fotosinteze i relativno niskom brzinom transpiracije. U Srbiji, suša značajno utiče na smanjenje prinos zrna kod kukuruza, posebno u poslednjoj deceniji. Zbog toga je glavni zadatak oplemenjivača stvaranje kukuruza tolerantnog na sušu koji će se uspešno nositi sa negativnim posledicama globalnog zagrevanja. Dalje poboljšanje tolerantnosti na sušu kod kukuruza je postalo vrlo ograničeno metodama konvencionalnog oplemenjivanja. Interdisciplinarnim pristupom se pokušava bolje proučiti i raščlaniti mehanizam tolerantnosti na sušu, ali je uspeh dosta limitiran. Od moderne genomike i genetike, zajedno sa dostignućima u fenotipskoj oceni, kao i saznanjima iz fiziologije i oplemenjivanja se očekuje da otkriju gene i procese koji su uključeni u tolerantnost na sušu.

Drought is a major abiotic stress factor limiting crop growth, development and production worldwide. The objective of this study was to evaluate tolerance to osmotic stress of maize seedlings. More than 6,000 accessions from the Maize Research Institute gene bank were tested under controlled drought (at flowering) in Egypt, and afterwards in temperate climate (Serbia and Macedonia). Out of 41 drought tolerant accessions in the field, five inbred lines were chosen for laboratory testing, as well as one drought sensitive line. These genotypes were exposed to 4% polyethylene glycol-PEG (Mr 10000) for 24 h and 48 h. Nine-day-old seedlings compared to control conditions were analyzed in root and shoot length, fresh and dry weight and proline content. Results showed reduction in all parameters under stress, while only proline content increased in all PEG treated genotypes compared to control., Suša je glavni abiotički stres koji ograničava porast, razvoj i produktivnost useva širom sveta. Cilj ovog rada bio je ocena tolerantnosti klijanaca kukuruza na osmotski stres. Više od 6.000 uzoraka banke gena Instituta za kukuruz testirano je u uslovima kontrolisanog stresa suše (faza cvetanja) u Egiptu, a posle toga u umerenom klimatu (Srbija i Makedonija). Od 41 uzorka tolerantnog na sušu u poljskim uslovima, odabrano je pet linija, kao i jedna osetljiva na sušu, za testiranje u laboratoriji. Ovi genotipovi su izloženi 4% polietilen glikolu (PEG, Mr 10000) u trajanju od 24 h i 48 h. Odgovor klijanaca izloženih stresu (starih 9 dana) u odnosu na kontrolu, analiziran je kroz porast korena i izdanka, svežu i suvu masu i sadržaj prolina. Rezultati su pokazali smanjenje svih parametara u uslovima stresa, dok je jedino sadržaj prolina bio u porastu kod svih ispitivanih genotipova pod uticajem PEG-a u odnosu na kontrolu.

Molecular and metabolic response of plants to a combination of two abiotic stresses is unique and cannot be directly extrapolated from the response of plants to each of the stresses individually. cDNA macroarray has become a useful tool to analyze expression profiles and compare the similarities and differences of various expression patterns. A macroarray of approximately 2,500 maize (Zea mays 1,.) cDNAs was used for transcriptome profiling in response to single and simultaneous application of water and high temperature stress of maize developing kernels at 15 days after pollination. All stress treatments (water stress-WS, heat stress-HS and their combined application-CS) induced changes in expression of 106 transcripts with 54 up-regulated and 52 down-regulated. There were 11 up-regulated and 15 down-regulated transcripts in common for all three stresses. Although these common transcripts showed existence of a mutual mechanism in stress response, the 23 transcripts induced only in CS indicate that plants responded in a different manner when exposed to simultaneous effects of both stresses. A glimpse of functions regulated under WS, HS and CS is provided, and also the common and different responses between individual and simultaneous stresses.

Maintenance of the original accessions identity and integrity is one of the priorities among genebank activities. Different factors related to conservation may result in accessions disruption. Regeneration is the most frequent critical point in this process, due to bottlenecks, inbreeding, random genetic drift and unintentional mixing or contamination. On the other hand, genetic drift may occur due to seed viability loss. Therefore, it is very important to establish the balance between the frequency of regeneration and the duration of accession conservation. The aim of the present study was to estimate whether the identity of accessions regenerated after 27 years of medium-term conservation was disrupted. Phenotypic markers were applied on three Maize Research Institute "Zemun Polje" (MRIZP) genebank maize landraces (K2026, K768 and K86), differing in seed viability, kernel type and effective population size. It was estimated that, after the regeneration, there had been no significant changes in the landrace K2026. There were some parameters indicating that genetic drift had occurred in the landrace K768, and that there had been even a certain degree of inbreeding in the landrace K86. According to the results, accession K2026 could still be kept under the same ID number. Due to the genuine identity disruption, assignment of new ID numbers for K768 and K86 should be suggested.

Increasing pressure on limited water resources for agriculture, together with the global temperature increase, highlight the importance of breeding for drought-tolerant cultivars. A better understanding of the molecular nature of drought stress can be expected through the use of genomics approaches. Here, a macroarray of approximate to 2500 maize cDNAs was used for determining transcript changes during water- and salt-stress treatments of developing kernels at 15 days after pollination. Normalization of relative transcript abundances was carried out using a human nebulin control sequence. The proportions of transcripts that changed significantly in abundance upon treatment (> 2-fold compared to the control) were determined; 1.5% of the sequences examined were up-regulated by high salinity and 1% by water stress. Both stresses induced 0.8% of the sequences. These include genes involved in various stress responses: abiotic, wounding and pathogen attack (abscisic acid response binding factor, glycine and proline-rich proteins, pathogenesis-related proteins, etc.). The proportion of down-regulated genes was higher than that for up-regulated genes for water stress (3.2%) and lower for salt stress (0.7%), although only eight genes, predominantly involved in energy generation, were down-regulated in both stress conditions. Co-expression of genes of unknown function under defined conditions may help in elucidating their roles in coordinating stress responses.

New high-throughput techniques, together with advances in analytical and computational technologies are enabling systemic investigations of molecular processes of biological systems. Clustering is widely applied by biologists in genome sequencing projects and phylogenetic studies. In the microarray expression analysis, the aim of cluster is to better organize but not to alter primary data: genes are visually organized according to the statistical transformation and calculation, due to the expression pattern in maize kernel during heat and water stress. Besides grouping together genes with similar patterns of expression, genes are represented by increased intensity of red, dig. green color, according to their up- or down-regulation in stress condition, compared to control., Nove tehnike, zajedno sa dostignućima u analitičkoj i kompjuterskoj tehnologiji omogućile su sistematsko ispitivanje molekularnih procesa u biološkim sistemima. Klaster analiza se široko primenjuje od strane biologa u programima sekvencioniranja genoma i filogenteskim proučavanjima. U proučavanju ekspresije gena korišćenjem "microarray" tehnike, cilj klaster analize je da se bolje organizuju, ali ne i zamene izvorni podaci: geni su vizuelno organizovani na osnovu statističkih transformacija i proračuna, a prema načinu ekspresije u uslovima toplotnog i vodnog stresa u zrnu kukuruza. Pored grupisanja gena sa sličnim načinom ekspresije, svaki gen je predstavljen različitim intenzitetom crvene, tj.zelene boje u zavisnosti od toga da li je utvrđeno povećanje ili smanjenje ekspresije gena u uslovima stresa u odnosu na kontrolu.

In maize (Zen mays L.) breeding programs, it is very important to define a genetic distance of inbred lines and to establish criteria and biometric methods for the satisfactory germplasm classification. A total of 29 inbred lines from Maize Research Institute "Zemun Polje" (MRIZP) breeding program, Belgrade, Serbia, were used to compare similarities obtained by morphological (according to UPOV- Union Internationale pour la Protection des Obtentions Vegetales) and molecular (simple sequence repeats, SSR) markers. The aim was to assess discriminative power of applied markers in the separation of related lines, and to determine the possibility of their application in choosing parental lines for breeding programs. Application of different marker types resulted in adequate separation of inbreds into divergent groups, which facilitates the choice of parental lines. However, there were still many inconsistencies between the field and laboratory results. The quality of information from morphological markers was improved by the application of the appropriate descriptor, measurement scale and the biometric method. According to the correspondence analysis, increased number of SSR markers will enable more reliable results. Regression analysis of morphological visual assessment (MVG) and SSR similarity of individual inbreds pointed out that in some cases morphological, and in others molecular markers more accurately reflected known pedigree information of tested maize lines. In the early generations of maize inbred lines testing, we propose utilization of information resulting from in orphologi cal markers, according to UPOV descriptor. However, application of adequate number of molecular (SSR) markers has an economic justification on a smaller number of elite lines in the later generations of line testing.

Global warming and predictions of climatic changes additionally put breeding for drought tolerance in the focus of breeding programmes for maize. Extensive studies on the existing gene bank collection of the Maize Research Institute "Zemun Polje" have been performed with the aim to identify and form initial sources for the development of maize inbreds more tolerant to drought. All accessions (about 6,000) were exposed to controlled drought stress in Egypt. Out of this number, approximately 8% of the tested genotypes were selected. In this study attention was given to 321 selected Western Balkan maize landraces, adapted to temperate climate growing conditions and the day length. Data derived from morphological characterization according to CIMMYT/IBPGR descriptors for maize, along with the application of numerical classification methods, were used to define homogeneous landraces groups based on morphological similarities. Results obtained from hierarchical and non-hierarchical analyses revealed the formation of 11 divergent groups. According to the obtained grain yield and visually scored stalk lodging and stay green, approximately 15% of the accessions from each of 11 groups were selected. Further investigations are towards defining their heterotic patterns and their possible utilization in developing and improving synthetic populations.

A collection of 2217 landraces from western Balkan (former Yugoslavia) is maintained at Maize Research Institute Zemun Polje gene bank. Nine flint and nine dent accessions from six agro-ecological groups (races), chosen on the basis of diverse pedigrees, were analyzed for genetic relatedness using phenotypic and simple sequence repeat (SSR) markers. One of the aims was to establish a reliable set of SSR markers for a rapid diversity analysis using polyacrilamide gels and ethidium bromide staining. In the principal component analysis (PCA) the first three principal components accounted for 80.86% of total variation and separated most of the flint from dent landraces. Ten SSR primers revealed a total of 56 and 63 alleles in flint and dent landraces, respectively, with low stuttering and good allele resolution on the gels. High average PIC value (0.822) also supports informativeness and utility of the markers used in this study. Higher genetic variation was observed among flint genotypes, as genetic distances between flint landraces covered a larger range of values (0.11-0.38) than between dent (0.22 - 0.33) genotypes. Both phenotypic and SSR analyses distinguished flint and dent landraces, but neither of them could abstract agro-ecological groups. The SSR method used gave clear, easy to read band patterns that could be used for reliable allele frequency determination. Genetic diversity revealed for both markers indicated that the landraces were highly adapted to specific environmental conditions and purposes and could be valuable sources of genetic variability.

According to regional reports on climate, more frequent and severe droughts and floods are already apparent. Modern maize breeding for different purposes (e.g. drought tolerance) emphasizes the importance for improved maize ability to withstand adverse environmental conditions. Genotypes with drought tolerance obtain high grain yield under optimal conditions and lower, but stable yield under dry environmental conditions. Field testing was conducted in 2014, on twenty-three maize inbred lines differing in drought tolerance. The inbreds were evaluated in respect to morphological traits (plant and ear height, total number of leaves, number of leaves above uppermost ear, ear leaf length and width), yield components and grain yield per plant. The experiment was set up according to RCB design with two replications. To simulate water stress, two plant densities were applied. According to Principal Component Analysis and cluster analysis, five inbred lines (T1, T2, T4, T8 i T15) performed the highest stability in both experimental conditions. Those inbreds could be used as a source for drought tolerance in breeding programs., Regionalna istraživanja klimatskih promena ukazuju na sve učestaliju pojavu promena u režimu padavina i temperatura. Za potrebe savremene selekcije za različite osobine (npr. tolerantnost prema suši), poboljšana sposobnost kukuruza da izdrži nepovoljne uslove spoljašnje sredine je esencijalna. U optimalnim uslovima, genotipovi tolerantni na sušu ostvaruju visok prinos, dok u uslovima vodnog deficita u kombinaciji sa visokim temperaturama vazduha ostvaruju niži, ali stabilan prinos. U poljskim ogledima 2014, izvršena je evaluacija dvadeset tri inbred linije kukuruza različite tolerantnosti na stres suše, praćenjem morfoloških osobina (visine biljke i gornjeg klipa, ukupnog broja listova i broja listova iznad gornjeg klipa, dižine i širine klipnog lista), komponenata prinosa i prinosa zrna po biljci. Ogled je sejan po kompletno randomiziranom blok dizajnu, u dva ponavljanja. Za simulaciju vodnog deficita, ogled je sejan u dve gustine. Poređenjem rezultata iz obe eksperimentalne gustine, dobijenih analizom glavnih komponenata i klaster analizom, pet samooplodnih linija kukuruza (T1, T2, T4, T8 i T15) su pokazale najveću stabilnost i mogu se smatrati poželjnim izvorima tolerantnosti prema suši za potrebe oplemenjivanja na ovo svojstvo.

The aim of this study was to investigate thirteen maize local landraces from Maize Research Institute (MRIZP) Gene Bank drought tolerant mini-core collection in respect to Fe, Mn and Zn content in grain. In addition, phytate (Phy) and β-carotene contents were determined. According to the results obtained, the highest Fe content was found in grain of LL3, whereas LL1and LL13 were the genotypes with the highest Mn, i.e. Zn content, respectively. However, due to the lowest level of Pphy, along with relatively higher level of Fe, Mn and Zn contents in grain, LL2 could be considered as valuable source in further breeding programs for improved mineral nutrient contents, particularly for Fe. Possible availability of investigated mineral elements was determined according to molar ratio between phytate as inhibiting factor and β-carotene as promoting factor for their absorption. Accordingly, genotype LL2, being with the lowest Pphy content, and genotype LL3, being with the highest β-carotene content (25.63 μg g-1) and the lowest phytate/β-carotene ratio, could be considered as potential sources of favorable genes for further breeding programs for improved nutritional quality, such as enhanced availability of investigated mineral elements., Cilj ovog istraživanja je bilo ispitivanje trinaest domaćih sorti kukuruza iz mini-core kolekcije za tolerantnost prema suši banke gena Instituta za kukuruz Zemun Polje (MRIZP), u pogledu sadržaja gvožđa (Fe), mangana (Mn) i cinka (Zn) u zrnu. Pored toga, određen je i sadržaj fitina (Phy) i β-karotena. Na osnovu dobijenih rezultata, najveći sadržaj gvožđa u zrnu imala je sorta LL3, dok su LL1 i LL13 bili genotipovi sa najvećim sadržajem mangana i cinka. Međutim, na osnovu utvrđenog najnižeg sadržaja fitinskog fosfora (Pphy), kao i relativno visokog sadržaja Fe, Mn and Zn, sorta LL2 bi se mogla smatrati izvorom poželjnih gena za buduće programe oplemenjivanja na povećan sadržaj mineralnih elemenata, naročito gvožđa. Moguća dostupnost ispitivanih mineralnih elemenata je određena na osnovu molarnih odnosa između fitina kao inhibitornog faktora i β-karotena kao promoterskog faktora za njihovu apsorpciju. Shodno tome, sorta LL2, kao genotip sa najnižim sadržajem fitinskog fosfora (Pphi), i sorta LL3, kao genotip sa najvišim sadržajem β-karotena (25.63 μg g-1) i najnižom vrednošću za odnos fitina i β-karotena, mogu se smatrati izvorima poželjnih gena za buduće programe oplemenjivanja na poboljšani nutritivni kvalitet zrna, kao što je povećana dostupnost ispitivanih mineralnih elemenata.

Maize Research Institute Zemun Polje (MRI) gene bank created an elite drought tolerant core collection of 40 accessions, based on field trials and general combining ability with inbred lines from the main heterotic groups (Lancaster, Iowa Stiff Stalk Synthetic BSSS and Iodent). A total of seven genetic groups were identified. Seven accessions showed good combining abilities with three testers from chosen heterotic groups, thus forming a distinctive genetic group (Unknown). In the present research, accessions with drought tolerance were also analyzed for grain quality, as these two traits are becoming highly important due to global warming and population growth. Kernel macronutrients contents (oil, protein and starch) were determined using Near Infrared Spectroscopy (NIR). Oil, protein and starch contents were significantly higher in introduced populations than in landraces for 0.43%, 0.12% and 0.85%, respectively (p lt 0.01). The greatest progress from the selection based on the expected genetic gain (Delta G) for 5% selection intensity would be obtained for oil (14.74%) followed by protein (10.14%). Landraces showed the least potential for the grain quality improvement due to the lowest expected Delta G for the three macronutrients. The differences between macronutrient content among genetic groups defined them as potentially favourable sources for a specific trait. According to Delta G values, the greatest progress in breeding would be accomplished for increased oil content with accessions from the Unknown group. Identification of the accessions with several favorable traits is valuable for simultaneous breeding for drought tolerance and grain quality.

Agronomic traits of 18 populations comprising a mini core collection for increased grain quality of the Maize Research Institute Zemun Polje were studied, along with two standard kernel type commercial hybrids. For almost all the traits (except root lodging) a considerable genetic variability was found, enabling successful breeding for any of them using this populations. Based on the obtained results, two populations were found to have grain yield at the level of ZP 341 commercial hybrid (one of them is from former Yugoslavia, and another is the introduced one). These two populations will be first to introduce into commercial breeding programs, if it proves they have also favorable biochemical characteristics. On the other hand, three populations had grain yield in the range of 1, 60-1, 91 t/ha, that is even lower than for commercial inbreeds. They will be excluded from the further breeding programs. Most of the populations were earlier than the commercial hybrids, during vegetation and according to the grain moisture at harvest. This is very favorable from a breeding standpoint. The worst characteristic of the population was very high stalk lodging, compared to commercial checks., U radu su proučavane agronomske osobine 18 populacija koje čine mini kor kolekciju Instituta za kukuruz Zemun Polje za poboljšani kvalitet zrna, kao i dva hibrida standardnog kvaliteta zrna. Za skoro sve ispitivane osobine (osim procenta poleglih biljaka) postoji dovoljna genetička varijabilnost koja se može iskoristiti u programima selekcije sa ovim materijalom. Na osnovu dobijenih rezultata izdvojene su dve populacije sa prinosom zrna na nivou standarda ZP 341 (jedna sa područja bivše Jugoslavije, a druga introdukovana), koje će se najpre uključiti u programe komercijalne selekcije, ukoliko budu zadovoljile i po svojim biohemijskim karakteristikama. S druge strane, tri populacije su imale prinos zrna u rasponu od 1,60-1,91 t/ha, što je niže i od elitnih inbred linija, i biće isključene iz daljeg selekcionog rada. Većina populacija bila je ranostasnija od komercijalnih hibrida, kako po vegetaciji, tako i po vlazi u zrnu, što je veoma povoljno sa stanovišta selekcije. Najveća uočena mana ovih populacija jeste veoma visok lom stabla u odnosu na komercijalne hibride.

Maize (Zea mays L.) landraces are an important source of genes for improving commercial germplasm. Today, drought tolerance and grain quality are major challenges in maize cultivation due to climatic changes and population growth. The Maize Research Institute gene-bank has a drought tolerant collection, which includes 13 landraces (from the former Yugoslavia) and 12 introduced populations (from different countries). These accessions were analyzed for protein, oil, starch and tryptophan contents, in order to identify drought tolerant accessions with high grain quality. Also, simple sequence repeat (SSR) analysis with specific primers for opaque2 recessive allele (o2) was carried out. All analyzed accessions showed high levels of protein. Oil content ranged from 3.75 % to 5.40 % and starch content from 67.5 % to 71.30%. Average protein content was not different (p lt 0.01) between landraces and introduced populations. Starch and oil contents were higher in introduced populations at 0.84 % and 0.39 %, respectively (p lt 0.01). Twenty-three accessions had high levels of tryptophan content. A high percentage of kernel type 1 and 2 indicated the presence of endosperm hardness modifier genes. Recessive o2 allele was found in most of the accessions. Absence of o2 in some high tryptophan accessions indicated action of another mutation. In two high tryptophan accessions an unknown band was detected. Absence of negative correlations between proteins, tryptophan and oil makes certain accessions suitable for use in the simultaneous improvement of target genotypes for these traits. Identified drought tolerant, high quality accessions can be used in breeding programs aimed at nutritional improvement of maize grown under drought conditions.

Suša je glavni abioticki faktor, koji znacajno utice na smanjenje i kvalitetkonacnog prinosa zrna kod kukuruza. S obzirom na predvidanja globalnih klimatskihpromena za 21. vek, u pravcu povecanja temperature vazduha, vece evapotranspiracije iucestalije pojave suše, poboljšana sposobnost kukuruza da izdrži nepovoljne uslovespoljašnje sredine je esencijalna i zahteva multidisciplinarni pristup u proucavanjuosobina koje doprinose njegovoj povecanoj tolerantnosti prema stresu suše.Za potrebe savremene selekcije kukuruza za razlicite osobine (npr. tolerantnostprema suši), materijal koji se cuva u banci gena Instituta za kukuruz “Zemun Polje”, posvom obimu (5806 genotipova) i ogromnoj genetickoj varijabilnosti, pruža velikemogucnosti. Testiranje celokupnog genofonda na tolerantnost prema suši je izvršeno uuslovima kontrolisane suše u Egiptu, kao i u uslovima umerenog vodnog deficita uZemun Polju i Skoplju, grupisanjem genotipova po dužini vegetacije (po grupamazrenja), kako bi svi bili izloženi stresu suše u približno istoj fazi vegetacionog perioda.Identifikacija i odabir genotipova su vršeni pracenjem sekundarnih osobina relevantnihza stres suše (ASI-a - anthesis silking interval, jalovosti biljke, ozrnjenosti klipa,nalivenosti zrna i osobine stay green-a), na sva tri lokaliteta, i merenjem prinosa zrna /biljci u uslovima umerenog vodnog deficita.Pored dobrih per se performansi u poljskim uslovima, za odabir genotipovanajtolerantnijih prema stresu suše, kao buducih komponenti hibrida, bila je neophodnainformacija o pripadnosti genotipova odgovarajucim heteroticnim grupama na osnovuukrštanja sa korišcenim inbred testerima, poreklom iz tri heteroticne grupe - BSSS,Lancaster i nezavisne, kao i informacija o opštoj kombinacionoj sposobnosti ukrštanjagenotipova sa odabranim inbred testerima. Od izuzetnog znacaja je bilo izdvajanje 6genotipova kukuruza, koji su se dobro kombinovali sa sva tri korišcena heteroticnaizvora, cineci potencijalno nov, sasvim razlicit izvor poželjne, Drought is a major abiotic factor, which significantly decreases final grain yieldand its quality in maize. Predictions of global climate changes for 21st century, towardshigher air temperatures, greater evapotranspiration and more frequent occurrence ofdrought, emphasize the importance for improved maize ability to withstand adverseenvironmental conditions, and the necessity of employing the multidisciplinaryapproach for studying the characteristics that contribute to its increased droughttolerance.The material maintained within The MRI “Zemun Polje” gene bank, consideringits size (5806 genotypes) and huge genetic variability of the accessions, offers the greatopportunity for modern maize breeding for different purposes (e.g. drought tolerance).Field testing for drought tolerance was performed on the entire MRI gene bankcollection, subjected to controlled drought in Egypt, as well as to conditions ofmoderate water deficit in Zemun Polje and Skopje. In order to expose them to droughtstress at aproximately the same vegetative stage, grouping the accessions into differentmaturity groups (acording to the duration of their vegetative period), was necessary.Identification and selection of the most drought tolerant genotypes was performed byvisual scoring of drought related secondary traits (ASI - anthesis silking interval,barrenness, seed set, grain filling and stay-green) at each location, and by measuringyield / plant under moderate water deficit conditions.Besides good performances per se in field, the information on combining abilityof selected material, in order to classify it into heterotic groups, was necessary to formthe core. Therefore, the most drought tolerant genotypes were crossed to three inbredtesters from heterotic groups that mutually combined well (BSSS, Lancaster andindependent source). It is very important that 6 genotypes had a good combining abilitywith all three observed heterotic sources, making them a new, completely differentsource of favourable

Agronomski biodiverzitet je širok pojam koji uključuje sve komponente biološkog diverziteta od značaja za hranu i poljoprivredu. On predstavlja rezultat interakcije između genetičkih resursa, životne sredine i upravljanja sistemima i prakse koji čine poljoprivrednu proizvodnju. Biljni genetički resursi, smatraju se izuzetno značajnim u obezbeđivanju dovoljne količine hrane neophodne za ljudsku ishranu. Procenjuje se da danas ukupno 30 useva obezbeđuju 95% čovekovih potreba za hranom. Kukuruz je jedna od najznačajnijih useva koja se gaji širom sveta. Iako poseduje izuzetno veliku genetičku varijabilnost, u komercijalnoj upotrebi se nalazi svega oko 5% ukupne germplazme kukuruza, koja obezbeđuje visoke prinose.Banka gena Instituta za kukruz „Zemun Polje“ održava kolekciju od 2217 lokalnih populacija kukuruza klasifikovanih u 18 agroekoloških grupa, sakupljenih na prostoru bivše Jugoslavije. Ispitivanje diverziteta lokalnih populacija predstavlja osnovni preduslov za njihovu efikasnu klasifikaciju, čuvanje i korišćenje, i ima za cilj procenu genetičke raznovrsnosti i strukture populacijaIspitana je genetička varijabilnost 54 lokalne (po tri populacije svake agroekološke grupe) i 6 introdukovanih populacija kukuruza (po dve iz Francuske, Gruzije i Kine). Za ispitivanje genetičke varijabilnosti populacija korišćeno je 18 morfoloških osobina i 10 RAPD (Random Amlified Polymorphic DNA) i 10 SSR (Simple Sequence Repeat) markera. Na osnovu morfoloških osobina urađena je analiza varijanse i uočene su značajne razlike kod svih osobina za različite izvore variranja što govori o visokom stepenu fenotipskog diverziteta između populacija. Takođe, dobijene su visoke vredosti heritabilnosti u širem smislu (preko 0,6) za skoro sve osobine, osim dužine granatog dela metlice. Rezultati PCA analize su ukazali da lokalne populacije kukuruza mogu biti okarakterisane pomoću osobina kao što su rast biljke, osobine metlice i karakteristike zrna, a zapaženo je i veće grupisanje tvrdunaca/polu, Agricultural biodiversity is a broad term which includes all components of biological diversity of relevance to food and agriculture. It represents the result of interaction between genetic resources, environmental protection and both management systems and practices that make agricultural production. Plant genetic resources are considered to be very important in providing sufficient amounts of food for human consumption. It is estimated that today a total of 30 crops provide 95% of human needs for food. Corn is one of the most important crops that are grown around the world. Although it has a very high genetic variability, only about 5% of the germplasm is in the commercial use, which provides high yields.Maize Research Institute „Zemun Polje“ genebank maintains a collection of 2217 maize landraces classified into 18 agro-ecological groups, collected in the former Yugoslavia. Evaluation of genetic diversity of the local population represents basic precondition for their effective classification, storage and use. It aims to assess the genetic diversity and population structure.Assessment of genetic variability was done on 54 maize landraces (three landraces from each agro-ecological group) and six introduced maize landraces (two of each from France, Georgia and China). In order to analyze genetic variability of maize landraces, 18 morphological traits, 10 RAPD (Random Amplified Polymorphic DNA) and 10 SSR (Simple Sequence Repeat) markers were used. Analysis of variance was performed for evaluate morphological traits. Significant differences were observed for all traits for different sources of variation which indicates a high degree of phenotypic diversity between populations. Also, high broad-sense heritability (over 0.6) were obtained for almost all the traits except branched tassel length. The results of PCA analysis indicated that local maize populations can be characterized by traits such as plant growth, tassel traits and kernel characteristics. It was also ob

Suša je glavni abioticki faktor, koji znacajno utice na smanjenje i kvalitet konacnog prinosa zrna kod kukuruza. S obzirom na predvidanja globalnih klimatskih promena za 21. vek, u pravcu povecanja temperature vazduha, vece evapotranspiracije i ucestalije pojave suše, poboljšana sposobnost kukuruza da izdrži nepovoljne uslove spoljašnje sredine je esencijalna i zahteva multidisciplinarni pristup u proucavanju osobina koje doprinose njegovoj povecanoj tolerantnosti prema stresu suše. Za potrebe savremene selekcije kukuruza za razlicite osobine (npr. tolerantnost prema suši), materijal koji se cuva u banci gena Instituta za kukuruz “Zemun Polje”, po svom obimu (5806 genotipova) i ogromnoj genetickoj varijabilnosti, pruža velike mogucnosti. Testiranje celokupnog genofonda na tolerantnost prema suši je izvršeno u uslovima kontrolisane suše u Egiptu, kao i u uslovima umerenog vodnog deficita u Zemun Polju i Skoplju, grupisanjem genotipova po dužini vegetacije (po grupama zrenja), kako bi svi bili izloženi stresu suše u približno istoj fazi vegetacionog perioda. Identifikacija i odabir genotipova su vršeni pracenjem sekundarnih osobina relevantnih za stres suše (ASI-a - anthesis silking interval, jalovosti biljke, ozrnjenosti klipa, nalivenosti zrna i osobine stay green-a), na sva tri lokaliteta, i merenjem prinosa zrna / biljci u uslovima umerenog vodnog deficita. Pored dobrih per se performansi u poljskim uslovima, za odabir genotipova najtolerantnijih prema stresu suše, kao buducih komponenti hibrida, bila je neophodna informacija o pripadnosti genotipova odgovarajucim heteroticnim grupama na osnovu ukrštanja sa korišcenim inbred testerima, poreklom iz tri heteroticne grupe - BSSS, Lancaster i nezavisne, kao i informacija o opštoj kombinacionoj sposobnosti ukrštanja genotipova sa odabranim inbred testerima. Od izuzetnog znacaja je bilo izdvajanje 6 genotipova kukuruza, koji su se dobro kombinovali sa sva tri korišcena heteroticna izvora, cineci potencijalno nov, sasvim, Drought is a major abiotic factor, which significantly decreases final grain yield and its quality in maize. Predictions of global climate changes for 21st century, towards higher air temperatures, greater evapotranspiration and more frequent occurrence of drought, emphasize the importance for improved maize ability to withstand adverse environmental conditions, and the necessity of employing the multidisciplinary approach for studying the characteristics that contribute to its increased drought tolerance. The material maintained within The MRI “Zemun Polje” gene bank, considering its size (5806 genotypes) and huge genetic variability of the accessions, offers the great opportunity for modern maize breeding for different purposes (e.g. drought tolerance). Field testing for drought tolerance was performed on the entire MRI gene bank collection, subjected to controlled drought in Egypt, as well as to conditions of moderate water deficit in Zemun Polje and Skopje. In order to expose them to drought stress at aproximately the same vegetative stage, grouping the accessions into different maturity groups (acording to the duration of their vegetative period), was necessary. Identification and selection of the most drought tolerant genotypes was performed by visual scoring of drought related secondary traits (ASI - anthesis silking interval, barrenness, seed set, grain filling and stay-green) at each location, and by measuring yield / plant under moderate water deficit conditions. Besides good performances per se in field, the information on combining ability of selected material, in order to classify it into heterotic groups, was necessary to form the core. Therefore, the most drought tolerant genotypes were crossed to three inbred testers from heterotic groups that mutually combined well (BSSS, Lancaster and independent source). It is very important that 6 genotypes had a good combining ability with all three observed heterotic sources, making them a new, completely diffe

Agronomski biodiverzitet je širok pojam koji uključuje sve komponente biološkog diverziteta od značaja za hranu i poljoprivredu. On predstavlja rezultat interakcije između genetičkih resursa, životne sredine i upravljanja sistemima i prakse koji čine poljoprivrednu proizvodnju. Biljni genetički resursi, smatraju se izuzetno značajnim u obezbeđivanju dovoljne količine hrane neophodne za ljudsku ishranu. Procenjuje se da danas ukupno 30 useva obezbeđuju 95% čovekovih potreba za hranom. Kukuruz je jedna od najznačajnijih useva koja se gaji širom sveta. Iako poseduje izuzetno veliku genetičku varijabilnost, u komercijalnoj upotrebi se nalazi svega oko 5% ukupne germplazme kukuruza, koja obezbeđuje visoke prinose. Banka gena Instituta za kukruz „Zemun Polje“ održava kolekciju od 2217 lokalnih populacija kukuruza klasifikovanih u 18 agroekoloških grupa, sakupljenih na prostoru bivše Jugoslavije. Ispitivanje diverziteta lokalnih populacija predstavlja osnovni preduslov za njihovu efikasnu klasifikaciju, čuvanje i korišćenje, i ima za cilj procenu genetičke raznovrsnosti i strukture populacija Ispitana je genetička varijabilnost 54 lokalne (po tri populacije svake agroekološke grupe) i 6 introdukovanih populacija kukuruza (po dve iz Francuske, Gruzije i Kine). Za ispitivanje genetičke varijabilnosti populacija korišćeno je 18 morfoloških osobina i 10 RAPD (Random Amlified Polymorphic DNA) i 10 SSR (Simple Sequence Repeat) markera. Na osnovu morfoloških osobina urađena je analiza varijanse i uočene su značajne razlike kod svih osobina za različite izvore variranja što govori o visokom stepenu fenotipskog diverziteta između populacija. Takođe, dobijene su visoke vredosti heritabilnosti u širem smislu (preko 0,6) za skoro sve osobine, osim dužine granatog dela metlice. Rezultati PCA analize su ukazali da lokalne populacije kukuruza mogu biti okarakterisane pomoću osobina kao što su rast biljke, osobine metlice i karakteristike zrna, a zapaženo je i veće grupisanje tvrdunaca/po, Agricultural biodiversity is a broad term which includes all components of biological diversity of relevance to food and agriculture. It represents the result of interaction between genetic resources, environmental protection and both management systems and practices that make agricultural production. Plant genetic resources are considered to be very important in providing sufficient amounts of food for human consumption. It is estimated that today a total of 30 crops provide 95% of human needs for food. Corn is one of the most important crops that are grown around the world. Although it has a very high genetic variability, only about 5% of the germplasm is in the commercial use, which provides high yields. Maize Research Institute „Zemun Polje“ genebank maintains a collection of 2217 maize landraces classified into 18 agro-ecological groups, collected in the former Yugoslavia. Evaluation of genetic diversity of the local population represents basic precondition for their effective classification, storage and use. It aims to assess the genetic diversity and population structure. Assessment of genetic variability was done on 54 maize landraces (three landraces from each agro-ecological group) and six introduced maize landraces (two of each from France, Georgia and China). In order to analyze genetic variability of maize landraces, 18 morphological traits, 10 RAPD (Random Amplified Polymorphic DNA) and 10 SSR (Simple Sequence Repeat) markers were used. Analysis of variance was performed for evaluate morphological traits. Significant differences were observed for all traits for different sources of variation which indicates a high degree of phenotypic diversity between populations. Also, high broad-sense heritability (over 0.6) were obtained for almost all the traits except branched tassel length. The results of PCA analysis indicated that local maize populations can be characterized by traits such as plant growth, tassel traits and kernel characteristics. It was also

Geneticists have been trying to explain adaptability and stability of a genotype in terms of a desirable combination of alleles expressed via epistasis. Stability determined in one set of data is very often stability of a genotype to a prevalent stress factor in a moment of carrying out the experiment. However, grain stability of a certain genotype can be a result of different factors, such as tolerance to drought, or to some important diseases and pests. Yield and yield stability of 15 maize hybrids were observed in 24 environments. The level of the interaction effect of studied maize hybrids was identified by the AMMI analysis, while a number of bands positively related to yield and stability of studied maize hybrids were identified by a genetic characterization by RAPD markers. Bands positively related to yields were present to a greater extent in parents originating from the BSSS population, while bands positively related to stability were more present in parents originating from the Lancaster population., Gentičari pokušavaju da objasne adaptabilnost i stabilnost genotipa u smislu poželjne kombinacije alela ispoljenih kroz epistazu. Međutim, stabinost definisana u jednom setu podataka je vrlo često zapravo stabilnost genotipa na dominantni stresni faktor u momentu izvođenja ogleda. Stoga, stabilnost rodnosti određenog genotipa može biti rezultat različitih faktora kao što su tolerantnost na sušu ili neku značajnu bolest ili štetočinu. U ovom radu ispitivan je nivo i stabilnost prinosa 15 hibrida kukuruza u 24 poljne sredine. Nivo interakcijskog efekta definisan je AMMI analizom. Genetička karakterizacija je urađena RAPD markerima. Trake pozitivno vezane za visok nivo prinosa su najčešće bile prisutne u roditeljima koji vode poreklo iz BSSS populacije dok su trake pozitivno vezane za stabilnost bile u značajnom procentu prisutne kod roditelja Lancaster populacije.

In gene-bank maize collection of Maize Research Institute Zemun Polje (MRI) two samples with untypical mtDNA profile for cytoplasmic male sterility (cms) were identified. These two samples showed typical multiplex polymerase chain reaction (PCR) band for cms-S, but also an additional band of unknown nature. It is assumed that the additional band is the result of a rearrangement of the two mitochondrial episomes characteristic for the cms-S in maize or a duplication of the part of cms-S mitochondrial genome. Additional field and laboratory experiments are necessary in the further lightening of this phenomenon., U banci gena kukuruza (Zea mays L.) Instituta za kukuruz Zemun Polje otkrivena su dva uzorka koja sadrže netipičan mitohondirjalni genom koji uzrokuje citoplazmatičku mušku sterilnost (cms). Ova dva genotipa pokazuju tipičnu multipleks polymerase chain reaction (PCR) traku za S-tip citoplazme, ali i dodatnu traku, čije je poreklo za sada nepoznato. Smatra se da je ona proizvod ili rearanžiranja dva mitohondrijalna epizoma karakteristična za cmsS kukuruza ili do sada još nesekvencioniranih gena koji uzrokuju cms. Za dodatnu potvrdu da je ovo zaista nov fenomen, uradili smo analizu svih poznatih izvora cmsS zajedno sa ova dva uzorka. Nijedan od analiziranih podtipova nije pokazao dodatnu traku koja je nađena u našim uzorcima. Dodatna poljska i laboratorijska istraživanja neophodna su u daljem razjašnjavanju ovog fenomena.

Maize Research Institute 'Zemun Polje' genebank maintains a collection of landraces grouped into 18 agro-ecological collected from ex-Yugoslavia territories. The application and comparison of different marker systems are important for the characterization and use of maize landraces in breeding program, as potential sources of desirable traits. In this study, 15 morphological traits, 7 RAPD primers and 10 SSR primer pairs were applied to i) to determine genetic distance between 21 maize dent landraces and ii) compare results obtained on morphological and molecular markers. Phenotypic analysis showed high level of heterogeneity between landraces. Higher level of genetic diversity was obtained with SSR than with RAPD. Genetic distance mean value for RAPD data was 0.35 i.e. for SSR 0.48. Based on the morphological traits and molecular markers, unweighted pairgroup method (UPGMA) analysis was applied for cluster analysis, using statistical NTSYSpc program package. Cluster analysis of morphological and molecular markers distances did not show the same population grouping. Better agreement with agro-ecological data was obtained with RAPD markers. Correlations between dissimilarity matrices for different types of markers were low. Data obtained in this work could be useful for further study of a larger number of landraces, and conservation of genetic resources and their genetic diversity., Banka gena Institut za kukuruz 'Zemun Polje' održava kolekciju lokalnih populacija grupisanih u 18 agro-ekološka prikupljenih na prostoru bivše Jugoslavije. Primena i upoređivanje različitih marker-analiza su važni za karakterizaciju i korišćenje lokalnih populacija kukuruza u selekcionim programima, kao potencijalnih izvora poželjnih osobina. U ovom radu 15 morfoloških osobina, 7 RAPD prajmera i 10 SSR prajmera su primenjeni sa ciljem i) utvrđivanja genetičke udaljenosti između 21 lokalnih populacija kukuruza zubana i ii) upoređivanja rezultata dobijenih na osnovu morfoloških i molekularnih markera. Fenotipska analiza je pokazala visok stepen heterogenosti između lokalnih populacija. Viši nivo genetičkog diverziteta je dobijen sa SSR nego sa RAPD markerima. Srednja vrednost genetičke distance za RAPD je bila 0.35, odnosno 0.48 za SSR. Na osnovu morfoloških osobina i molekularnih markera, pomoću UPMGA analize dobijeni su klasteri, koristeći NTSYSpc statistički program. Klaster analiza na osnovu morfoloških i molekularnih markera nije pokazala isto grupisanje lokalnih populacija. Bolje slaganje sa agroekološkim podacima je dobijeno na osnovu RAPD markera. Korelacije su bile niske između genetičkih distanci za različite tipove markera. Rezultati dobijeni u ovom radu mogu biti od koristi za dalje proučavanje većeg broja lokalnih populacija, kao i očuvanje genetičkih resursa i njihovog genetičkog diverziteta.

As one of the most important agricultural crops, maize is a staple diet for a large portion of the continuously growing world's human population. Unfortunately, its production is severely affected by adverse environmental stresses such as drought, salt, low and high temperatures. The mechanisms of drought stress tolerance in maize are quite complex and involves a signaling network of genes that controls its adaptation to the stress. Recently, many transcription factors (TFs) for tolerance to drought stress have been identified in maize. In this study, specifically designed primers were used to identify functional single nucleotide polymorphisms (SNPs) in the MYB-like protein E1 (MYBE1) gene of 26 tolerant and sensitive maize inbred lines from the gene banks of Maize Research Institute "Zemun Polje", Serbia and Maize Research Institute, Kneja, Bulgaria by PCR amplification and direct sequencing. Multiple alignments of the sequenced fragments to the drought sensitive US maize inbred B73 and other inbred lines, representing the functional diversity of maize, from the Panzea database (http://www.panzea.org/) was performed. The sequence alignment revealed several SNPs in inbred lines object of this study, one of which unique to the drought tolerant Serbian inbreds T3, T5, T6, T7 and T8. In these lines, the A→G transition, located in the acidic Ser/Thr - rich region of the gene, leads to amino acid change from Tryptophan to Alanine at the corresponding position of the protein. This replacement does not affect the binding site of MYBE-1 transcription factor, but possibly reflects the spatial conformation through changing of its functional activity. This study will contribute the identification of functional markers in genes implicated in the development of drought stress tolerance and their further use for genomic improvement in the national maize selection programs.

Quality protein maize (QPM) is high lysine (tryptophan) maize with hard endosperm and good agronomic performance. QPM was developed primarily for utilization in tropical and sub-tropical regions where maize is a staple food. Its adaptation and cultivation in temperate areas is still not fully developed, although QPM could have merits for production and consumption in developed parts of the world, especially as animal feed. Maize Research Institute Zemun Polje has a program on developing QPM genotypes for growing in temperate regions. The objective of our research was initial screening of 72 hybrids (derived from crosses between QPM lines adapted to temperate environments and three commercial lines with standard kernel quality) for kernel modification, tryptophan and protein contents, quality index (QI) and grain yield. Five hybrids with high tryptophan content (0.071 to 0.081%) and yield at the level of standard hybrids (96 - 114%) were identified. Protein content ranged from 10 to 11.20%, similar to standard hybrids. QI was in the range from 0.71 to 0.74, which was better than in standard hybrids (0.57 - 0.62), but below the QPM threshold of 0.80. The percentage of good kernel modifications (type 1 and 2) was over 80% in three and over 74% in two hybrids. The results indicated the complexity of obtaining high yielding hybrids with high levels of essential amino-acids. Identified potential QPM hybrids have to be further evaluated for agronomic traits, but the results can be considered important in the context of limited information on QPM adapted to temperate environmental conditions.

Grain yield is the primary trait of interest in maize breeding programs. Worldwide, drought is the most pervasive limitation to the achievement of yield potential in maize. Drought tolerance of maize has been considerably improved through conventional breeding. Traditional breeding methods have numerous limitations, so development of new molecular genetics techniques could help in elucidation of genetic basis of drought tolerance .In order to map QTLs underlying yield and yield components under drought 116 F3 families of DTP79xB73 cross were evaluated in the field trials. Phenotypic correlations calculated using Pearson's coefficients were high and significant. QTL detection was performed using composite interval mapping option in WinQTL Cartographer v 2.5. Over all nine traits 45 QTLs were detected: five for grain yield per plant and 40 for eight yield components. These QTLs were distributed on all chromosomes except on chromosome 9. Percent of phenotypic variability determined for the identified QTLs for all the traits was in the range from 27.46 to 95.85%. Different types of gene action were found for the QTLs identified for analyzed traits., Prinos je najvažnije svojstvo u programima oplemenjivanja kukuruza, a suša je glavni ograničavajući faktor u postizanju optimalnog prinosa. Značajno poboljšanje tolerantnosti na sušu kod kukuruza ostvareno je metodama konvencionalnog oplemenjivanja. Međutim, tradicionalne metode oplemenjivanja imaju brojna ograničenja, pa se zahvaljujući razvoju novih metoda molekularne genetike može postići napredak u rasvetljavanju genetičke osnove tolerantnosti na sušu. U cilju mapiranja QTL-ova za prinos i komponente prinosa kod kukuruza u uslovima suše izvršeno je fenotipsko ocenjivanje 116 F3 familija ukrštanja DTP79xB73 u polju. Fenotipske korelacije između ispitivanih svojstava su izračunate pomoću Pirsonovog koeficijenta i bile su visoke i značajne. Za identifikaciju QTL-ova korišćena je composite interval mapping opcija u programu WinQTL Cartographer v 2.5. Detektovano je ukupno 45 QTL-ova za devet analiziranih svojstava: pet za prinos i 40 za osam komponenti prinosa. QTL-ovi su detektovani na svim hromozomima izuzev na hromozomu 9. Procent fenotipske varijabilnosti identifikovan za sve QTL-ove za sva ispitivana svojstva bio je u opsegu od 27.46 do 95.85%. Različiti tipovi genskih efekata detektovani su za različite QTL-ove za analizirana svojstva.

A collection of 2217 landraces from former Yugoslavia region is maintained at Maize Research Institute Zemun Polje gene bank. All local varieties from the former Yugoslavia are classified into 18 groups. These agroecological groups encompass early introduced flint types grown on small and isolated areas, later introduced dent types that spread on wide areas of crop production and types created through hybridization between these two kernel types. The objective of this research was to study population structure, genetic diversity and relationships of nine flint and nine dent accessions belonging to different agro-ecological groups using phenotypic and simple sequence repeat (SSR) markers. The 18 analyzed landraces displayed great variation for most analyzed traits, but flint landraces were more diverse. Ten SSR probes revealed total of 56 and 62 alleles in flint and dent landraces, respectively. Eight specific alleles (i.e. alleles found only in one landrace or only within flint, i.e. dent landraces) were detected with five probes. One specific allele was found in flint and seven alleles in dent landraces. These differences in allele structure point to different origins and possibly different purposes of flint and dent genotypes. Both phenotypic and SSR analyses could distinguish most flint and dent landraces, but not agro-ecological groups. The results revealed a significant genetic heterogeneity indicating that the analyzed landraces could be valuable sources of genetic variability., Kolekcija od 2217 lokalnih populacija sa teritorija Jugoslavije se održava u banci gena Instituta za kukuruz Zemun Polje. Populacije su klasifikovane u 18 agro-ekoloških grupa, koje obuhvataju rano introdikovane tipove tvrdunaca, kasnije inrodukovane tipove zubana i tipove nastale njihovom hibridizacijom. Cilj ovog rada je bio da se utvrdi struktura i genetička divergentnost, pomoću fenotipskih i SSR markera, devet populacija tvrdunaca i devet populacija zubana koji pripadaju različitim agro-ekološkim grupama. Analizirane populacije su pokazale visok stepen varijacija za većinu analiziranih osobina, mada su populacije tvrdunaca bile raznovrsnije. Ukupno 56 alela je detektovano u populacijama tvrdunaca, odnosno 64 u populacijama zubana, pomoću deset SSR markera. Osam specifičnih alela (alela detektovanih samo medu tvrduncima, odnosno zubanima) je identifikovano pomoću pet proba - jedan alel medu tvrduncima i sedam medu zubanima. Ove razlike u alelnoj strukturi ukazuju na razlicito poreklo i različite namene genotipova tvrdunaca i zubana. Fenotipska i SSR analiza su mogle da razdvoje većinu tvrdunaca od zubana, ali ne i agro-ekološke grupe. Rezultati su pokazali značajnu genetičku heterogenost analiziranih populacija, koja bi mogla biti dragocen izvor genetičke varijabilnosti.

Suša je jedan od najvažnijih ogranicavajucih faktora u proizvodnji kukuruza, pa je poboljšanje tolerantnosti na sušu od veoma velikog znacaja u programima oplemenjivanja. Stvaranje genotipova tolerantnih na sušu je veliki izazov zbog variranja u pojavljivanju, intenzitetu i trajanju stresa suše, zbog geneticke kompleksnosti ovog stresa i izraženih interakcija genotip-sredina. Identifikacija kvantitativnih lokusa vezanih za tolerantnost na sušu je važno sredstvo za indirektnu selekciju pomocu molekularnih markera. Istovremena primena konvencionalnog sa molekularnim oplemenjivanjem, marker-asistiranom selekcijom i genetickim inžinjeringom može doprineti bržem nacinu za poboljšanje tolerantnosti na sušu kod gajenih biljaka. Identifikacija lokusa za kvantitativna svojstva (QTL) za tolerantnost na sušu kod kukuruza je urađena na genetickom materijalu dobijenom ukrštanjem linija DTP79 (izvor tolerantnosti na sušu) i B73 (linija osetljiva na sušu). Za konstruisanje molekularne mape neophodne za identifikaciju QTL-ova, korišcena je F2 generacija (John Innes Centre (JIC), Norwich, United Kingdom). Podaci o vrednostima svojstava potencijalno ukljucenih u odgovor kukuruza na stres suše su dobijeni analizom F3 familija u poljskim ogledima. Molekularna mapa i dobijene vrednosti za ispitivana svojstva su korišcene za detekciju QTL-ova. Na osnovu informacija o QTL-ovima je vršeno utvrivanje postojanja uzrocne povezanosti izmeu dva ili više svojstava. Fenotipske korelacije su izracunate primenom Pearson-ovog koeficijenta i bile su visoko znacajne za izvestan broj ispitivanih osobina. Identifikacija QTL-ova je uraena primenom ANOVA metode i metoda statistickog programa WinQTL karotgrafera, v 2.5. Prikazani su samo rezultati dobijeni primenom CIM (WinQTL karotgrafer, v 2.5) i ANOVA metode. Za ispitivanih 26 osobina primenom CIM metode je detektovano 147 QTL-ova, od kojih je 93 detektovano i primenom ANOVA metode. Ukupna fenotipska varijabilnost objašnjena identifikovanim QTL-ovima za, Drought is one of the most important limiting factors in maize production. Improving drought tolerance is therefore of outmost importance for breeding. Achieving this goal is a big challenge due to the variability in timing, intensity and duration of drought, genetic complexity of drought tolerance and large genotype by environment interactions. Identification of quantitative loci for drought tolerance is very imporatant for indirect selection using molecular markers. Conventional breeding together with molecular breeding, marker-assisted selection and genetic engineering could contribute to drought tolerance improvement of cultivated plants. Quantitative trait loci (QTLs) for drought tolerance were identified in a maize population derived from a cross between two lines - DTP79 (drought tolerant) and B73 (drought sensitive). Map construction (John Innes Centre (JIC), Norwich, United Kingdom) was done using F2 generation and the coresponding F3 progenies were evaluated for the traits potentialy related to drought tolerance in field trials. Phenotypic and marker data were used for QTL detection. Possible causal relationships between two or more traits were determined according to information about QTLs. Phenotypic correlations calculated using Pearson’s coefficients were highly significant for some of the analyzed traits. ANOVA and methods of WinQTL Cartographer 2.5 were employed to identify QTLs. Results of ANOVA and CIM option in WinQTL cartographer, v 2.5 are presented. A total of 147 QTLs were detected using CIM for the analyzed traits. Out of this number, 93 were also detected using ANOVA. Percent of phenotypic variability determined for the identified QTLs for all of the traits ranged from 11.85% (RWC) up to 91.16% (LW3). Mapping analysis identified genomic regions associated with two or more traits in a manner that was consistent with phenotypic correlation between traits, supporting the possible existence of linked genes or pleiotrophy that influence these tra

Water deficit is one of the main limiting factors leading to maize yield reduction in the temperate zone. Global environmental changes additionally put breeding for drought tolerance in the focus of research programmes. In improving drought tolerance of elite hybrids, the first step is identification of drought tolerance sources within the existing gene bank collections. The complete gene bank collection of the Maize Research Institute, Zemun Polje, Serbia, was field tested under extreme water deficit in Egypt, with the aim of identifying tolerant genotypes. Six quantitative traits and a general estimation of the plant habitus during the growing season were estimated. Genotypes were classified by two-step cluster analysis. In the first phase of data analysis the classification was done with four quantitative and one qualitative trait, genotypes being classified into two clusters. In the second phase when the analysis included the duration of the growing season, genotypes were classified into three clusters. The first phase of data analysis pointed out to 231 drought tolerant genotypes, while the second phase data analysis further added a certain number of early and medium early genotypes, giving a total of 558 accessions. Further work on the selected accessions will be continued for the formation of the core collection and direct use in breeding.

Drought is one of the most important factors contributing to crop yield loss. Developing maize varieties with drought tolerance requires exploring the genetic basis of yield and associated agronomic traits. In order to identify QTLs for yield and drought related traits and to determine their relationships, 116 F-3 families of the DTP79xB73 cross were evaluated in field trials. Phenotypic correlations between the traits were calculated using Pearson's coefficient. QTL detection was performed using ANOVA and composite interval mapping (CIM). Out of 64 QTLs identified using CIM for all analyzed traits 26 QTLs were also identified with ANOVA. For all the traits (except for EL, DS2 and RWC1) only a small proportion of phenotypic variation was accounted for by the identified QTL. The significant positive/negative phenotypic correlations between different traits and coincidence of markers with allelic differences in the expected direction show that they may be causally correlated. The above criteria were fullfilled for a subset of QTLs within all the traits. The overlap found between the QTLs for yield and those for the other traits suggests the presence of genes with pleiotropic effects on the investigated traits. Results will be used for further investigation and detection of possible candidate genes for drought tolerance in maize.

Due to an unknown mechanism of genetic control and great environmental effects in the process of trait expression, morphological markers are often considered unreliable indicators of genetic relationships. Morphological characterization of 19 maize inbreds was done according to the UPOV descriptor, while molecular characterization was performed with RAPD markers. Based on the estimation of phenotypes according to the UPOV descriptor, the squared Euclidean distance was calculated and then, on the basis of this distance, a morphological similarity matrix was formed. Jaccard similarity coefficients were calculated on the basis of presence absence of bands on gels in the RAPD analysis. When data were standardized, the comparison between morphological and genetic similarity of observed maize inbreds was done. The correlations varied from 0.47 (inbred L 217) to 0.76 (inbred L 86). The average value of correlations for all studied inbreds amounted to 0.64. Furthermore, the results of the cluster analysis for both markers, molecular and morphological, had high concordance with pedigree data. Environmental effects were decreased in morphological markers (according to the UPOV descriptor) by rescaling a measurement scale from a scale to an ordinal level of measurement and in such a way results of morphological markers approached results of molecular markers in the estimation of the genetic distance (GD) of maize inbred lines., Zbog nepoznatog mehanizma genetičke kontrole i velikog uticaja spoljne sredine u procesu ekspresije svojstava, o morfološkim markerima se cesto govori kao o nepouzdanim pokazateljima genetičkih odnosa. Morfološka karakterizacija 19 linija kukuruza je urađena po UPOV deskriptoru, vizuelnom ocenom grupe biljka, dok je molekularna karakterizacija urađena RAPD markerima. Na osnovu ocena fenotipa po UPOV deskriptoru izračunati su kvadrati euklidskog rastojanja na osnovu kojih je formirana matrica morfoloških sličnosti. Na osnovu prisustva-odsustva traka na gelovima u RAPD nanalizi izračunati su koeficijenti genetičkih sličnosti po Jaccardu. Nakon toga vršena su poređenja morfoloških i genetičkih sličnosti ispitivanih linija kukuruza. Korelacije su se kretale od 0.47 za liniju L 217 do 0.76 za liniju L 86. Prosečna vrednost korelacija za sve ispitivane linije je iznosila 0.64. Rezultati klaster analize, kako za molekularne tako i za morfološke markere, bili su u visokoj saglasnosti sa pedgre podacima. Degradiranjem merne skale sa skalnog na ordinarni nivo merenja, kod morfoloških markera (po UPOV deskriptoru), je ublažen efekat spoljne sredine. Na taj način su se rezultati morfoloških markera približili rezultatima molekularnih makera u proceni GD inbred linija kukuruza.

The study includes research on the effect of ultrasound on the ability of seed germination and coleoptile development of cereal landraces (fam. Poaceae): oat (Avena sativa L.) brodski, rye (Secale cereale L.) rakotinska, Triticale svetinikolsko and soft wheat (Triticum aestivum L.) govrlevska. The experiment with ultrasound was carried out at frequency of 30-40 kHz on the thermostatic ultrasonic bath. Seeds were sonicated at a constant temperature (25ºC) for 15 min. Ultrasound effect is reflected in the length of the coleoptyl and mesocotyl, although in a good deal is genetically predetermined. Coleoptile length was the longest in Triticale (3.3-5.5 cm) and approximately the same lengths are evident in rye (3.0-6.1 cm). Concerning the mesocotyl the longest one (5.525 cm ± 0.697) is recorded at rye, even significantly longer than control of oat and Triticale. Longer coleoptile of sonicated seeds indicates faster seedling development, good water supply and rapid development and emergence of first leaves. Correlation coefficient showed very high (0.821) and high R2 (67,472%) dependence among variables both, in length of coleoptiles (as dependent variable) and mesocotyl (as independent) with low standard error (0.225). With the simple use of ultrasound the germination period could be shorten, water supply more efficient, the sowing periods will be shorten and good yields even under conditions of climate change with increased temperatures could be achieved., Studija istražuje efekat ultrazvuka na dužinu koleoptila i mezokotila kod klijanaca starih autohtonih sorata iz fam. Poaceae: ovas (Avena sativa L.) brodski, raž (Secale cereale L.) rakotinska, Triticale svetinikolsko i pšenica (Triticum aestivum L.) govrlevska. Tretmani su izvedeni sa frekvencijom od 30-40 kHz u termostatskom ultrazvučnom kupatilu na konstantnoj temperaturi od 25ºC u trajanju od 15 min. Ultrazvučni efekat se reflektuje na dužinu koleoptila i mezokotila, i pored toga što je njihov rast genetski predodređen. Najduži koleoptil je izmeren kod Triticale-a (3.3-5.5 cm) i približne dužine kod raži (3.0-6.1 cm). Najduži mezokotil razvija raž (5.525 cm ± 0.697). Veća dužina koleoptila u semena tretiranom ultrazvukom ukazuje na brži razvoj klijanaca, bolji vodni režim i brži razvoj i pojavu prvih listova. Korelacioni koeficijent je vrlo visok (0.821) kao i R2 (67,472%) što ukazuje na zavisnost varijabli dužina koleoptila (zavisna) i dužina mezokotila (nezavisna). Upotrebom ultrazvuka može se skratiti period klijanja, poboljšati vodni režim, a ranijim setvom dobiti zadovoljavajući prinosi i u uslovima globalnih klimatskih promena.

It is generally known that a phenotype is formed on the basis of the capacity of its genotype affected by environmental factors. Yield stability is statistically expressed through the GxE interaction. The interaction is a part of the trial variation that includes the factor of the genotype and the factor of the environment. The presence of the qualitative interaction significantly makes difficult the selection of the best genotypes in the process of breeding. As long ago as the early 1960s, many researchers noticed that the application of linear regression could, in many cases, define adaptability and stability of a genotype. However, in cases when data are not well adjusted to the linear model, better results can be gained by the application of the multivariate models (PCA, AMMI, GGE). The estimated maize hybrid stability was compared in this study by linear (Finlay and Wilkinson and Eberhart and Russell models) and multivariate statistical models (AMMI model). Very similar results were obtained by all three models. It was probably due to one dominant factor in the hybrid x environment interaction (different precipitation sums for the environments and the length of the growing season for hybrids). The advantage was given to the AMMI model, as the model with one axis analyses the interaction equally well as linear models, while the model with two axes extracted another part of systemic variation of the interaction effect not adjusted to the linear model., Opšte je poznato da se fenotip formira na osnovu kapaciteta svog genotipa pod uticajem faktora spoljašnje sredine. Prisustvo kvalitativne interakcije značajno otežava izbor najboljih genotipova u procesu selekcije. Još su ranih šezdesetih godina istraživači primetili da se primenom linearne regresije može, u velikom broju slučajeva, definisati adaptabilnost i stabilnost genotipa. Međutim, u slučajevima kada podaci nisu dobro prilagođeni linearnom modelu bolji rezultati se postižu primenom multivarijacionih modela (PCA, AMMI, GGE). U ovim istraživanjima izvršeno je poređenje procene stabilnosti hibrida kukuruza pomoću linearnih (Finlay i Wilkinson, Eberhart i Russell, modeli) i multivarijacionog modela statistike (AMMI model). Sva tri modela su dala veoma slične rezultate. Prednost se ipak daje AMMI modelu jer model sa jednom osom podjednako dobro kao i linearni modeli analizira interakciju, dok je model sa dve ose izdvojio još jedan deo sistematske varijacije interakcijskog efekta koji nije prilagođen linearnom modelu.

Drought is one of the most important factors contributing to crop yield loss. In order to develop maize varieties with drought tolerance, it is necessary to explore the genetic basis. Mapping quantitative trait loci (QTL) that control the yield and associate agronomic traits is one way of understanding drought genetics. QTLs associated with grain yield (GY), leaf width (LW3, LW4) plant height (PH), ear height (EH), leaf number (NL), tassel branch number (TBN) and tassel length (TL) were studied with composite interval mapping. A total of 43 QTLs were detected, distributed on all chromosomes, except chromosome 9. Phenotypic variability determined for the identified QTLs for all the traits was in the range from 20.99 to 87.24%. Mapping analysis identified genomic regions associated with two traits in a manner that was consistent with phenotypic correlation among traits, supporting either pleiotropy or tight linkage among QTLs., Suša je jedan od najznačajnijih faktora koji utiče na smanjenje prinosa. Mapiranje lokusa za kvantitativna svojstva (QTL) koja kontrolišu prinos i vezane agronomske osobine daju uvid u genetičku osnovu odgovora biljke na stres suše i omogućavaju stvaranje tolerantnih genotipova. Lokusi za kvantitativna svojstva vezani za prinos, širinu lista, visinu biljke, visinu biljke do klipa, broj listova, broj grana metlice i dužinu metlice identifikovani su primenom composite interval mapping metode. Detektovano je ukupno 43 QTL-a, na svim izuzev na 9 hromozomu. Fenotipska varijabilnost za ova svojstva bila je u opsegu od 20.99 to 87.24%. Identifikovani su genomski regioni vezani za dva ili više svojstva, i istovremeno je kod njih detektovana visoka fenotipska korelacija, što ukazuje na postojanje plejotropnih ili epistatičkih interakcija između QTL-ova.

Maize Research Institute (MRI) gene bank maintains a collection of 6000 maize accessions. Within this collection over 100 sources of cytoplasmic male sterility (CMS) were found in field trials, i.e. more than 2% of the total accession numbers. These sources are distributed among Yugoslav open-pollinated varieties (4.56% of them contain CMS), as well as introduced heterozygous genotypes and inbred lines. In order to identify cytoplasm types the gene-bank sources of CMS were screened using a PCR assay with specific primers for C, T and S cytoplasms. Predominant cytoplasmic male sterility type among the analyzed accessions was CMS-S. Results were inconclusive for three accessions, i.e. different results for the progenies of two ears per accession were obtained. For another two accessions a new PCR product profile was identified, consisting of one band characteristic for CMS-S and one unspecific for any of the three CMS types. The PCR approach enabled a simple, fast and reliable large scale screening of maize cytoplasm among MRI gene bank accessions, significantly reducing time for cytoplasm characterizations compared to classical method of testing with restorers for each known type of CMS.

Although the reveal of heterotic groups in maize significantly increased testing efficiency, field trials are still unreplaceable and most time and fund consumable in the process of the hybrid development. The efficiency of breeding programmes could be significantly increased if the hybrid performance could be predicted prior to the field evaluation. Although different marker techniques have been developed and included into current breeding programmes, the satisfactory results have not been obtained yet. The present study is an attempt to inexpensively and rapidly discover indicators that could even partially facilitate the selection of parental pairs in the process of the hybrid development prior to the field evaluation. The phenotypic description of inbred lines according to the UPOV Descriptor was used for the estimation of the phenotypic distances for which it had been assumed that they could, to a certain degree, be an indicator of heterosis. The phenotypic characterization according to the UPOV Descriptor was done for 28 elite inbreds, that are often used in our commercial breeding programmes, and for 24 inbreds originating from the same source, as well as, for an inbred of the unknown origin and their phenotypic distances were estimated. The cluster analysis resulted in the classification that was in high compliance with known information on the origin. It was empirically concluded that great distances of parent inbreds result in good hybrids. Furthermore, high values among certain inbreds belonging to the same heterotic groups are observed on the morphological distance matrix and crosses among them should indeed be tested in the field prior to making any general conclusion on the reliability of the morphological distance in the prediction of heterosis., Efikasnost oplemenjivačkih programa bi se znatno mogla povećati ako bi bilo moguće predvideti proizvodne performase hibrida pre evaluacije u polju. Fenotipska karakterizacija linija po UPOV deskriptoru je iskorišćena za izračunavanje fenotipskih distanci za koje smo pretpostavili da u određenoj meri mogu biti indikator heterozisa. Urađena je i fenotipska karakterizacija po UPOV deskriptoru 28 elitnih linija koje se često koriste u komercijalnom programu oplemenjivanja u Institutu za kukuruz 'Zemun Polje', 24 linije poreklom iz istog izvora kao i jedne linije nepoznatog porekla i na osnovu rezultata urađena je Klaster i Korespondenciona analiza. Klaster analiza je dala grupisanje koje je u visokoj saglasnosti sa poznatim informacijama o poreklu. Empirijski je zaključeno da velike distance roditeljskih linija daju dobre hibride. Međutim, na matrici morfoloških distanci se uočavaju visoke vrednosti između nekih linija koje pripadaju istim heterotičnim grupama i ukrštanja između njih bi svakako trebalo testirati u polju, pre izvlačenja nekog generalnog zaključka o pouzdanosti morfološke distance u predviđanju heterozisa.

Characterization and evaluation of the genetic resources provide breeders with valuable information on an effective utilization of the genetic resources in breeding programs. In this paper we present the results of different research programs aimed at identification of superior genotypes among MRI gene bank accessions, regarding stress tolerance (drought and herbicides), better nutritional quality (phosphorus) and specific traits (cytoplasmic male sterility - CMS). Fifty-two genotypes were identified as a potential source for drought tolerance. Considering herbicide tolerance only genotypes with resistance to the Pivot were found. Within 100 sources of CMS in the collection S cytoplasm was identified as the predominant type. Phytate analysis of 60 maize populations identified three groups of populations - with low (8), intermediate (25) and high (27) phytate content. The results of these researches, which are a part of pre-breeding activities, will be included in MRI breeding programs, with the aim of developing new genotypes with improved traits important in commercial maize breeding and seed production., Karakterizacija i evaluacija genetičkih resursa omogućava njihovo efikasno korišćenje u različitim selekcionim programima. U ovom radu predstavljamo rezultate različitih istraživanja usmerenih na identifikaciju superiornih genotipova iz banke gena Instituta za kukuruz, a u pogledu tolerantnosti na stres (sušu i herbicide), poboljšanih nutritivnih vrednosti (fitin) i specifičnih svojstava (citoplazmatičnu mušku sterilnost - CMS). Kao potencijalni izvor tolerantnosti na sušu identifikovano je 52 genotipa. Među uzorcima ispitivanim na herbicide nađeni su samo genotipovi tolerantni na Pivot. Što se tiče specifičnih svojstava među 100 identifikovanih izvora citoplazmatične muške sterilnosti S tip citoplazme je bio dominantan. Analizom fitina 60 populacija kukuruza identifikovane su tri grupe populacija - sa niskim (8), srednjim (25) i visokim (27) sadržajem fitina. Rezultati ovih istraživanja, koji predtsavljaju deo pre-breeding aktivnosti, će biti uključeni u selekcione programe Instituta za kukuruz, sa ciljem razvijanja novih genotipova sa poboljšanim svojstvima značajnim u oplemenjivanju kukuruza i semenskoj proizvodnji.

A lethal albino seedling mutant of maize that is resistant to imazethapyr was found in the material from the Maize Research Institute, Zemun Polje, gene bank, The mutation was characterized by a normal development of the first two leaves, with white coloration appearing from the third to the fifth leaves, at the base of the leaves spreading towards their end, resulting in the death of the whole plant. While the upper leaves were dying, the first two were still green for eight to ten days. It seemed that the mutation was conditioned by one recessive allele.

Standard induction processes of delayed fluorescence (DF) of chlorophyll (induction signals) occur when an intact leaf segment of maize inbreds and hybrids is kept in the phosphoroscope darkroom for more than 15 minutes (t > 15 min), and at the same time the leaf is illuminated with the intermittent white light. Resolved induction processes of DF chlorophyll into transients: A, B, C, D and E occur when the intact leaf segment of maize inbreds and hybrids is kept in the phosphoroscope darkroom for a significantly shorter period (500 s > t > 30 s), with the time rate t of 30 s, prior to its illumination with the intermittent white light. Induction transients: A, B, C, D and E are characterized with the time of their generation: tA = 31±6 ms (A), tB = 5 ± 0,5 s (B), tC = 15±5 s (C), tD = 360±20 s (D) and tE = 670±35 s (E), dynamics of changes in transients intensities (IA, IB, IC, ID and IE) and mechanisms of their generation. The induction processes of chlorophyll DF of the intact leaf of maize inbreds and hybrids resolved into transients: A, B, C, D and E are accompanied by the occurrence and different levels of activation energy (Ea, kJ mol-1) that correspond to critical temperatures ranging from 28 to 33°C. The generation mechanisms of induction transients A, B, C, D and E classify them into two groups. Transients A and B are of a physical character, while the transients: C, D, and E are of a chemical character. It is shown that the generation of the induction transients: B, C, D and E simultaneously follows establishing of the oscillations of induction processes of the DF chlorophyll. Oscillating of induction processes of DF chlorophyll is explained by the ion (K+, Na+, H+, Cl-) transport mechanism across the thylakoid membrane of the intact leaf of maize inbreds and hybrids grown under conditions of air drought, increased temperatures and water deficiency in the medium., U ovom radu ostvaruje se primena poboljšanog fotosintetično-fluorescentnog metoda u proučavanju složenih indukcionih procesa zakasnele fluorescencije (ZF) hlorofila, koji su razloženi na tranzijente: A, B, C, D i E i kod kojih mogu da nastanu oscilacije. Međuzavisnost oscilacija i indukcionih tranzijenata: A, B, C, D i E javlja se kod intaktnih listova linija (ZPR 70ž i Oh 43) i hibrida (ZPDC 360, ZPSC 46A, ZPSC 704 i ZPSC 71) kukuruza koji su gajeni u staklari u uslovima različite vazdušne suše, delovanja viših temperatura i deficita vode u podlozi. Posebno se ukazuje na uslove pri kojima dolazi do uspostavljanja standardnih indukcionih procesa ZF hlorofila. Daje se kraći opis standardne indukcione krive ZF hlorofila. Znatno detaljnije daju se eksperimentalni rezultati o razlaganju indukcionih procesa ZF hlorofila na tranzijente: A, B, C, D i E. Pokazani su vremenski i fizičko-hemijski parametri za proučavane indukcione tranzijente. Objašnjeni su njihova priroda i mehanizmi nastajanja. Utvrđene su karakteristike i mehanizam nastajanja oscilacija indukcionih procesa ZF hlorofila. Dati su uslovi pri kojima dolazi do pojave pobuđenog stanja, nastajanja fluktuacija i uspostavljanja oscilacija indukcionih procesa ZF hlorofila u tilakoidnoj membrani intaktnog lista linija i hibrida kukuruza. Izneta je hipoteza o mehanizmu nastajanja oscilacija. Objašnjena je međuzavisnost uspostavljanja oscilacija i tranzijenata indukcionih procesa ZF hlorofila.

The remarkable development and application of new genetic technologies over the past decades has been accompanied by profound changes in the way in which research is commercialized in the life sciences. As results, new varieties of commercially grown crops with improved or new traits are developed. Many thousands of patents which assert rights over DNA sequences have been granted to researchers across the public and private sector. The effects of many of these patents are extensive, because inventors who assert rights over DNA sequences obtain protection on all uses of the sequences. Extremely valuable to breeders in the national agricultural research system is the ability to genotype their collections to get a clear picture of their diversity and how diversity could be enhanced through sharing and access to global collections. The issue of the eligibility for patenting of DNA sequences needs to be reopened. Patents that assert rights over DNA sequences and their uses are, in some cases, supportable, but in others, should be treated with great caution. Rights over DNA sequences as research tools should be discouraged. That the best way to discourage the award of such patents is by stringent application of the criteria for patenting, particularly utility. A more equitable, ethically - based food and agricultural system must incorporate concern for three accepted global goals: improved well being, protection of the environment and improved public health (particular point food from GMO). To mitigate conflict one of the approach to solve problem is ethical and truthful label of GM food, because consumers have a right to choose whether to eat genetically modified foods or not. Interesting examples and risks as consequences of free availability of genetic resources utilization, its transformation, patenting of 'new' organism and selling it back to the genetic resource owner are presented. Society has obligations to raise levels of nutrition and standards living by all res, Razvoj novih biotehnologija zasnovanih na tehnologiji rekombinantne DNK, definisanih kao genetičko inženjerstvo, izazvao je značajne promene u načinu primene i komercijalizacije naučnih rezultata dobijenih u oblasti osnovnih istraživanja, posebno u poljoprivredi, medicini i zaštiti životne sredine. Na hiljade patenata koji daju pravo na vlasništvo nad DNA sekvencama/genima je odobreno istraživačima u privatnom i javnom sektoru. Korišćenjem patentiranih gena, koji kontrolišu važne osobine (otpornost prema bolestima na pr.) stvorene su i uvedene u proizvodnju nove sorte i hibridi najznačajnijih gajenih biljnih vrsta kao što su kukuruz, soja, pirinač kao i mnoge ukrasne biljke. Istraživači koji su vlasnici patenta gena imaju pravo na patentnu zaštitu i transgenih biljaka koje poseduju taj gen. Od posebnog značaja za istraživače u poljoprivredi, posebno u oblasti genetike i oplemenjivanja je mogućnost, korišćenjem genskih proba, karakterizacije genotipova i dobijanje pouzdanih podataka o genetičkoj varijabilnosti, naročito u korišćenju kako u sopstvenim programima tako i u razmeni biološkog materijala sa drugim kolekcijama. Slobodna dostupnost tih proba je jedan od preduslova. Pitanje opravdanosti patentiranja sekvenci DNA/gena i njihovog korišćenja je neophodno ponovo otvoriti jer su patenti u nekom slučaju opravdani a unekom moraju da budu oprezno razmatrani.. Patentno pravo na sekvencu DNA/gen kao eksperimentalni materijal nije opravdano i treba ga obeshrabrivati. Najbolji način za ograničavanje zloupotrebe je strogo primena kriterijuma za patentiranje, posebno za pravo korišćenja patenata. Mnogo pravedniji, na etičkim principima zasnovan sistem proizvodnje hrane mora da ima ugrađena tri globalna cilja: poboljšanje kvaliteta života, zaštitu životne sredine i obezbeđenje zdravlja populacije sa akcentom na korišćenje hrane proizvedene od GMO. Jedan od pristupa ostvarenju ovih ciljeva je etičko i istinito obeležavanje hrane od GMO, jer potrošači imaju pravo izbora da li

Vancetovic J., S. Mladenovic Drinic, M.Babic, D. Ignjatovic Micic and V.Andelkovic (2010): Maize genebank collections as potentially valuable breeding material. - Genetika, Vol. 42, No. 1, 9 - 21. Characterization and evaluation of the genetic resources provide breeders with valuable information on an effective utilization of the genetic resources in breeding programs. In this paper we present the results of different research programs aimed at identification of superior genotypes among MRI gene bank accessions, regarding stress tolerance (drought and herbicides), better nutritional quality (phosphorus) and specific traits (cytoplasmic male sterility - CMS). Fifty-two genotypes were identified as a potential source for drought tolerance. Considering herbicide tolerance only genotypes with resistance to the Pivot were found. Within 100 sources of CMS in the collection S cytoplasm was identified as the predominant type. Phytate analysis of 60 maize populations identified three groups of populations with low (8), intermediate (25) and high (27) phytate content. The results of these researches, which are a part of pre-breeding activities, will be included in MRI breeding programs, with the aim of developing new genotypes with improved traits important in commercial maize breeding and seed production.

In order to broaden the genetic base of maize (Zea mays L.) germplasm, it is necessary to integrate exotic materials into adapted breeding materials. The aim of the study was to compare antioxidative systems of two adapted maize inbred lines (A and B) with exotic germplasm, Drought Tolerant Population (DTP), and their backcrosses with DTP (A1, A2 and B1, B2). The content of low-molecular weight antioxidants, proline and phenolics, as well as antioxidant capacity, detected as free radical scavenging activities against DPPH radical, were measured in maize seeds. Proline content in both, embryo and endosperm was higher in backcrosses than in inbred lines and DTP, and increased in embryo by getting higher percentage of exotic germplasm. Contrary, phenolic content and DPPH radical scavenging activity of seeds, which were higher in adapted inbred lines than in DTP, were slightly decreased in their backcrosses with DTP., U cilju proširenja genetičke osnove germplazme kukuruza (Zea mays L.), neophodna je inkorporacija egzotičnog u lokalni adaptirani selekcioni materijal. U radu su upoređeni antioksidativni sistemi dve lokalne inbred linije (A i B) sa antioksidativnim sistemima egzotične germplazme (DTP) i povratnih ukrštanja tih inbred linija i DTP-a (A1, A2, B1 i B2). U semenu kukuruza meren je sadržaj antioksidanata male molekulske težine, prolina i ukupnih fenola, kao i antioksidativni kapacitet, izražen preko sposobnosti hvatanja slobodnih DPPH radikala. Rezultati su pokazali porast nivoa prolina, kako u klici, tako i u endospermu, kod A1, A2, B1 i B2 genotipova, u odnosu na čiste inbred linije i DTP. Takođe, nivo prolina se povećavao sa povećanjem udela egzotične germplazme. Nasuprot tome, kod čistih inbred linija je bio veći nivo ukupnih fenola i stepen hvatanja slobodnih DPPH radikala nego kod DTP-a, i sa tendencijom neznatnog smanjenja kod A1, A2, B1 i B2 genotipova.

Since the mid 1960's, when the Maize Research Institute "Zemun Polje" began its maize breeding activities, there have been five cycles of selection primarily referring to the period of introducing new, higher-yield hybrids into mass production. This paper provides genetic characterization Of 30 maize hybrids developed by the Maize Research Institute "ZenlUn Polje", by RAID markers, in order to determine genetic relatedness of hybrids of different breeding cycles. The Jaccard similarity coefficients have been Computed and used for Cluster analysis by UPGMA and by Wards' method, discriminant analysis and correspondence analysis. Cluster analysis clearly delineates groups of hybrids by time cycles, while the correspondence analysis indicates that a division into three cycles Could be more adequate. The territorial map of the discrimination area, reduced to two dimensions, is an indication of the proximity between the cycles III and IV. Also the proximity of group centroids, of different cycles, by delineation lines indicates that the discrimination among groups is not so strong. The results Of all three analysis indicate that in genetic terms there -,ire three different selection cycles. Introduction of novel germ plasma into existing breeding material implies, in genetic terms, a beginning of new selection cycle.