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The development of drought-tolerant genotypes capable to reconfigure their metabolic pathways to cope with water deficit is of utmost importance for plant breeding. Further progress in maize performance under drought is expected by combining marker-assisted breeding with metabolite markers. Due to the fact that grain is more susceptible to water stress than vegetative tissues, the prediction of grain yield from the biochemical parameters of the leaves is a challenge. Hence, by evaluating five maize inbred lines differing in drought tolerance, the aim of this study was (i) to determine whether the tolerance/susceptibility to water stress can be attributed to the level of phenolic acids in maize leaves and (ii) to evaluate the relationship between these metabolites and grain yield as an indicator of plant productivity. Water deficit caused the reduction of protocatechuic, caffeic, and sinapic acid in all inbreds evaluated. However, the highly pronounced increase of ferulic and especially cinnamic acid content under water deficit conditions indicated a possible crucial role of these secondary metabolites in preventing the harmful effects of water deficit stress, making them quite promising metabolic markers for maize breeding, as those in the well-watered condition were correlated to grain yield in water deficit conditions, allowing selection under optimal growth conditions.

Maize Research Institute „Zemun Polje“ gene bank preserves ex-situ an active collection (5806 accessions). Local landraces are the most significant, since they were created by natural selection and adapted to local growth conditions. In the last 15 years, in MRIZP gene bank was conducted identification of superior genotypes for specific traits and drought tolerant and improved grain quality core collections were established. Moreover, exchange of inbred lines from MRIZP gene bank and Agricultural Institute Osijek working collections, genotyping and phenotyping of inbreds, and statistical analysis of molecular and agronomic data, is conducted through ongoing Project “Harmonization of methods for phenotyping, genotyping and management of genetic resources in maize”. Although the accessions conserved in gene banks are valuable sources for breeding varietes more nutritious, productive and resilient to pests, diseases and climatic changes, there is a limited information of their agronomic characteristics. To overcome this, the European Evaluation Network (EVA) was established in 2019 by the European Cooperative Programme for Plant Genetic Resources (ECPGR). All activities within the EVA networks are intended at the pre-breeding stage, to increase the knowledge about publicly available crop germplasm, with aim to introducing these into breeding programmes. Through crop-specific public–private partnerships, maize EVA is generating standardized evaluation data (both the phenotypic and the genotypic) for numerous accessions and landraces available in European gene banks. During the project, a total of 95 MRIZP accessions will be genotyped and evaluated in multilocation experiments for futher use by breeding companies.

Southeast Europe (SEE) is a very important maize-growing region, comparable to the Corn belt region of the United States, with similar dent germplasm (dent by dent hybrids). Historically, this region has undergone several genetic material swaps, following the trends in the US, with one of the most signifcant swaps related to US aid programs after WWII. The imported accessions used to make double-cross hybrids were also mixed with previously adapted germplasm originating from several more distant OPVs, supporting the transition to single cross-breeding. Many of these materials were deposited at the Maize Gene Bank of the Maize Research Institute Zemun Polje (MRIZP) between the 1960s and 1980s. A part of this Gene Bank (572 inbreds) was genotyped with Afymetrix Axiom Maize Genotyping Array with 616,201 polymorphic variants. Data were merged with two other genotyping datasets with mostly European fint (TUM dataset) and dent (DROPS dataset) germplasm. The fnal pan-European dataset consisted of 974 inbreds and 460,243 markers. Admixture analysis showed seven ancestral populations representing European fint, B73/B14, Lancaster, B37, Wf9/Oh07, A374, and Iodent pools. Subpanel of inbreds with SEE origin showed a lack of Iodent germplasm, marking its historical context. Several signatures of selection were identifed at chromosomes 1, 3, 6, 7, 8, 9, and 10. The regions under selection were mined for protein-coding genes and were used for gene ontology (GO) analysis, showing a highly signifcant overrepresentation of genes involved in response to stress. Our results suggest the accumulation of favorable allelic diversity, especially in the context of changing climate in the genetic resources of SEE.

Popcorn is a type of specialty maize and plays important role in the history and the spread of this species. This type of maize historicaly received little atention in genetic diversity studies while the fact is that information on genetic variability and population structure is of crucial importance for improvement of breeding programs. The genetic variation of popcorn maize was mainly analysed using SSR markers, but there are not many studies applying high-density SNP markers with lower genotyping errors. The aim of this study was the assesment of genetic diversity and population structure of popcorn germplasm which represents the genetic resources currently used in breeding programs in Maize Research Institute „Zemun Polje“. Molecular characterization of 44 popcorn genotypes was done using 25k SNP Illumina Infinum Array for maize. After quality control filtering, 12335 SNPs were selected for downstream analyses. Genetic distance detected ranged from 0.001 to 0.51 with an average of 0.33. The majority of genetic distances (70.6%) fell between 0.30 and 0.51 revealing significant genetic variability in a set of maize genotypes under study. SNP markes were moderatly informative with an average PIC value of 0.26. Also, for more than 50% of SNPs, PIC value was greater than 0.30. The average observed heterozygosity was 0.04 ranging from 0 to 0.11. The clustering, principal component and model-based STRUCTURE analyses showed similar grouping of popcorn lines, generally in accordance with their genetic background. The results of this research gave valuable information for initiation of future breeding strategies.

Maize (Zea mays L.) is one of the major crops of the world for feed, food, and industrial uses. It was originated in Central America and introduced into Europe and other continents after Columbus trips at the end of the 15th century. Due to the large adaptability of maize, farmers have originated a wide variability of genetic resources with wide diversity of adaptation, characteristics, and uses. Nowadays, in Europe, maize is mainly used for feed, but several food specialties were originated during these five centuries of maize history and became traditional food specialties. This review summarizes the state of the art of traditional foodstuffs made with maize in Southern, South-Western and South-Eastern Europe, from an historic evolution to the last research activities that focus on improving sustainability, quality and safety of food production.

Early maturity is very important factor in the yield, grain moisture and plant density game, contributing to cost-efficient maize production. Landraces conserved in gene banks present a promising basis to enrich diversity of early maize breeding material. To start and speed-up the mobilization of currently scattered, unknown and underused maize genetic resources maintained in ex situ Maize Research Institute Zemun Polje gene bank collection, 63 landraces, as new potential sources of earliness and low grain moisture at harvest, were selected for evaluation of their test-cross performance with two divergent early testers. The majority of landraces (29), with prevailed flint type, exhibited heterosis for yield in crossings with BSSS-ID tester (102NS), where 20 top-crosses expressed grain moisture below defined threshold value (21.1%). The best performing landraces can be used as a starting-point of new pre-breeding programme for flint maize breeding material broadening. In parallel, nine landraces expressed simultaneous heterosis in crossings with flint tester (14NS), exhibiting grain moisture above threshold value. Simultaneous heterotic effect with two divergent inbred testers implied to the existence of an independent heterotic pool. These findings will contribute to broadening of maize breeding material for earliness and low grain moisture at harvest as important goals in maize breeding.

Plants reconfigure their metabolic pathways to cope with water deficit. The aim of this study was to determine the status of the physiological parameters and the content of phenolic acids in the upper most ear leaf of maize inbred lines contrasting in drought tolerance in terms of improved plant productivity e.g., increased grain yield. The experiment was conducted under irrigation and rain-fed conditions. In drought-tolerant lines, the effect of water deficit was reflected through a chlorophyll and nitrogen balance index increase followed by a flavonols index decrease. The opposite trend was noticed in drought susceptible inbreds, with the exception of the anthocyanins index. Moreover, in comparison to irrigation treatment, opposite trends in the correlations between grain yield and physiological parameters found under water deficit conditions indicated the activation of different metabolic pathways in defense against water deficit stress. Concerning phenolic acid content, water deficit caused the reduction of protocatechuic, caffeic, and sinapic acid in all inbreds evaluated. However, the highly pronounced increase of ferulic and especially cinnamic acid content under water deficit conditions indicated possible crucial role of these secondary metabolites in preventing the harmful effects of water deficit stress, which, in turn, might be useful in maize breeding selection for drought tolerance

Due to the loss of agro-biodiversity, there is a strong effort to find apparent and efficient mechanisms for the conservation and sustainable use of genetic diversity. A joint monitoring of the diversity and collections structure of the Montenegrin maize landraces conserved in the Serbian (MRIZPGB) and Montenegrin (MGB) gene banks has been conducted in order to improve the composition of the collections and to identify and eliminate possible redundancy. Based on a separate analysis of white- and yellow-orange maize landraces, it can be concluded that the diversity and evolution of distinct maize landraces grown and collected in Montenegro have been simultaneously shaped by both environmental (i.e., natural selection) and socially driven factors (farmers’ selection, migration and colonization processes of the human population). Although it has been determined that the authenticity and variability of the Montenegrin maize landraces gene pool have largely been preserved in the MRIZPGB collection, a significant amount of redundancy was observed. The obtained results will contribute to the cost-efficient conservation of the maize gene pool in the Montenegrin and Serbian gene banks. The recognized and well-preserved original variability of the MRIZPGB and MGB Montenegrin gene pool represents a valuable source for pre-breeding activities on broadening the white and flint maize breeding programmes under temperate conditions.

In the second half of 20th century the awareness of importance of landraces for the future, led to organized collecting missions for numerous plant species. A total of 2217 maize (Zea mays L.) landraces, collected in the former Yugoslavia, are stored at Maize Research Institute (MRIZP) gene bank. During 2014, new collecting missions were organized in the eastern and western parts of Macedonia. According to collecting site and kernel type, 14 samples from the Faculty of Agricultural Sciences and Food, R. Macedonia were chosen for the comparison and identification of possible duplicates, through coupling with the 16 MRIZP gene bank accessions from the same area and kernel characteristics. Phenotypic characterization was done for 21 traits according to International Board for Plant Genetic Resources descriptors for maize. The Principal Component Analysis (PCA) identifies five PCs with Eigenvalue > 1, explaining 80% of the total phenotypic variation. The most discriminative traits with the strongest positive associations were tasseling and silking dates, plant height, leaf length and ear length. Compared to the ex-situ populations, the number of alleles and the number of specific alleles, showed a significant decrease in the in situ populations. Twelve unique alleles were detected in samples from MRIZP gene bank, and only four were found in new Macedonian samples. Cluster analysis of morphological and molecular markers distinguished groups of maize accessions with distinctive morphological traits and genetic profiles that will be useful for conservation, and management of gene bank collection, as well as for possible utilization in breeding.

Soybean, as a plant species, is native to regions with conditions favourable of humidity and temperatures for its growth and development. The expansion of the soybean growing area resulted in requirements of varieties with higher tolerance and more stable grain yield under drought conditions. In order to develop high yielding varieties, the method of full-sib (FS) selection was applied in this study, as one of many methods of recurrent selection. The basic principle of recurrent selection is a cyclic selection, with the aim to accumulate favourable alleles. Three most yielding F2:3 sister lines obtained from the crossing combination of varieties Kunitz and Kador, were used for two combinations. Progenies of two FS crossing combinations were tested in two locations during two years (2011 with more favourable and 2012 with less favourable precipitation distribution). The values of grain yield per plant, the most important components of yield and morphological traits decreased under less favourable conditions. The highest decrease was recorded in the number of pods and the number of grains per plant, whereas the lowest decrease was found for the 1000-grain weight. Regardless of the relatedness of the tested material, significant differences in response to drought were observed not only between two FS progenies, but also within progenies of each combination. Soybean grain yield is a complex trait strongly affected by environmental conditions. Under unfavourable conditions, the reductions in the following traits were observed in progenies of two sister combinations: grain yield per plant (26.5-36.0% and 25.6-42.7%), number of pods per plant (18.6-33.0% and 12.6-38.2%) and the number of grains per plant (18.1-30.2% and 14.3-37.6%). Three progenies of FS crossings with the lowest yield reduction were identified as suitable initial material for the development of varieties with higher tolerance to drought conditions., Soja, kao biljna vrsta, potiče iz regiona sa povoljnim uslovima vlage i temperature za njen rast i razviće. Sa širenjem areala gajenja soje, nastala je potreba za sortama sa većom tolerancijom i stabilnijim prinosima zrna u uslovima suše. U cilju stvaranja prinosnih sorti, za formiranje materijala u ovom radu, korišćena je metoda ukrštanja u punom srodstvu (FS) koja pripada metodama rekurentne selekcije. Osnovni princip ove grupe metoda su ukrštanja u ciklusima u cilju akumulacije poželjnih gena. Iz kombinacije ukrštanja sorti Kunitz i Kador, odabrane su tri najprinosnije F2:3 linije, za dve FS kombinacije ukrštanja. Potomstva dve FS kombinacije ukrštanja su na dve lokacije u toku dve godine (2011 sa povoljnijim i 2012 sa manje povoljnim rasporedom padavina). Vrednosti prinosa zrna po biljci, najvažnijih komponenti prinosa i morfoloških osobina su se smanjile u manje povoljnim uslovima. Najviše se smanjio broj mahuna i broj zrna po biljci a najmanje masa 1000 zrna. Bez obzira na srodnost testiranog materijala, uočene su značajne razlike reakcije na sušu, kako između dva FS potomstva, tako i unutar potomstava svake kombinacije. Prinos zrna soje je kompleksna osobina pod jakim uticajem uslova spoljne sredine. U nepovoljnim uslovima kod potomstava dve sestrinske kombinacije ukrštanja, došlo je do smanjenja prinosa zrna po biljci od 26.5-36,0% i 25,6-42.7%, broja mahuna po biljci od 18.6-33.0% i 12.6-38.2%, broja zrna po biljci od 18.1-30,2% i 14.3-37.6%. Identifikovana su tri potomstva iz FS ukrštanja sa najmanjim smanjenjem prinosa pogodna kao početni materijal za stvaranje linija i sorti sa većom tolerancijom prema uslovima suše.

Although accompanied with adverse low temperatures, early maize sowing could be used to avoid drought during flowering and diminish yield losses. Herein, a small-scale experiment of low temperature stress (LTS) on maize lines L1 (tolerant), L2 (medium tolerant) and L3 (susceptible) is presented. Plants were grown in pots exposed to exterior suboptimal (March) and optimal (late April) temperatures until three leaf stage. Chlorophyll (CH), flavonoids (FL), anthocyanins (AN) and nitrogen balance (NBI) indices were measured using Dualex Scientific optical device. Growth parameters were also determined. Under LTS, number of plants was unchanged for L1 and halved for L2 and L3. Compared to L2 and L3, L1 had significantly higher (p<0.05) shoot fresh weight (0.649 g vs. 0.406 g and 0.303 g), AN (0.17 vs. 0.13) and FL (1.47 vs. 1.38 and 1.36). For recovery evaluation, plants were transplanted into the field. Transplanted stressed L1 plants showed the highest grain yield per plant (55g) in the field. Due to high correlations (p<0.01) between FL in three leaf stage and grain yield per plant, FL could be used as an indicator of plant recovery of maize genotypes exposed to LTS during early sowing., Ranom setvom kukuruza se može izbeći efekat suše u fazi cvetanja i tako preduprediti smanjenje prinosa uprkos nepovoljnim temperaturama u tom periodu. U ovom istraživanju prezentovani su rezultati efekta niskih temperatura na tri linije kukuruza: L1 (tolerantna), L2 (srednje osetljiva) i L3 (osetljiva). Biljke su gajene do faze trećeg lista u saksijama izloženim suboptimalnim (mart) i optimalnim (april) spoljnim temperaturama. Sadržaj hlorofila, flavonoida i antocijana kao i nitrogen balance index (NBI) su mereni korišćenjem uređaja Dualex Scientific (Force-A, Orsay, France). Takođe, mereni su i parametri rasta. U poređenju sa L2 i L3, L1 je imao značajno veću (p<0.05) svežu masu nadzemnog dela biljke (0.649 g vs. 0.406 g i 0.303 g), antocijana (0.17 vs. 0.13) i flavonoida (1.47 vs. 1.38 i 1.36). Biljke su presađene u polje radi procene oporavka. Presađene biljke genotipa L1 su pokazale najveći prinos po biljci u polju (55g). S obzirom na visoku korelaciju između sadržaja flavonoida u fazi trećeg lista i prinosa po biljci (p<0.01), flavonoidi mogu biti korišćeni kao indikator oporavka biljke kukuruza izloženih niskim temperaturama u fazi rane setve

Maize Research Institute „Zemun Polje“ (MRIZP) gene bank preserves ex-situ an active collection (5806 accessions), thus ranking among the five largest European national maize gene bank collections. Local (i.e. western Balkan) maize landraces (2217 accessions) are considered to be the most significant genotypes, since they represent the original biological material created by the process of natural selection and adapted to local growth conditions, thus offering the great opportunities for different breeding purposes and contributing to yield increase. Currently, they are not directly used in breeding, but rather for development of synthetic populations or core collections for the traits of interest, allowing the integration of the most valuable traits (adaptability, variability, divergence and heterotic potential). In the last 15 years, in MRIZP gene bank was conducted identification of superior genotypes regarding specific traits (cytoplasmatic male sterility) and abiotic stress tolerance (herbicides tolerance). In response to more frequent unpredictable and extreme climatic events, as well as to growing demand for healthy food and feed, in MRIZP gene bank were established drought tolerant and improved quality core collections through implementation of long-term pre-breeding programmes, as the most promising way of linking genetic resources and commercial breeding programmes. Moreover, exchange of maize inbred lines from MRIZP gene bank and Agricultural Institute Osijek working collections, genotyping and phenotyping of inbreds, and statistical analysis of molecular and agronomic data, is conducted through ongoing Project “Harmonization of methods for phenotyping, genotyping and management of genetic resources in maize”. Joint analysis of genetic diversity originated from the Western Balkan Corn Belt, along with comparative analysis with the same standards (available genome sequencing data of public lines), will enable the determination of heterotic pattern, removal

Maize, wheat and rice are the most important cereals grown in the world. It is predicted that by 2025 maize is likely to become the crop with the greatest production globally. Conservation of maize germplasm provides the main resources for increased food and feed production. Conservation in gene banks (ex-situ) is dominant strategy for maize conservation. More than 130 000 maize accessions, e.g. about 40% of total number, are stored in ten largest gene banks worldwide and Maize Research Institute Zemun Polje (MRIZP) gene bank, with about 6000 accessions, is among them. Organized collecting missions started in 1961. in the former Yugoslavian territory, and up today, more than 2000 local maize landraces were stored. Pre-breeding activities that refer to identification of desirable traits from unadapted germplasm within genebank, result in materials expected to be included in breeding programs. Successful examples are LAMP, GEM and GENRES projects. At the end of XX century, at MRIZP genebank two pre-breeding activities were undertaken: eco-core and elite-core collections were created and landraces fulfilled particular criteria were chosen. In the last decade, MRIZP genebank collection was used for identification of sources for drought tolerance and improved grain quality. According to agronomic traits and general combining ability, two mini-core collections were created and included in commercial breeding programs., Pšenica, pirinač i kukuruz su tri najznačajnije žitarice u svetu, ali se procenjuje da će se do 2025. godine kukuruz najviše proizvoditi. Konzervacija germplazme kukuruza predstavlja glavni izvor poželjnih gena koji mogu poslužiti za povećanje obima i kvaliteta proizvodnje kukuruza, a time i hrane za ljude i životinje. Dominantna strategija za konzervaciju kukuruza je ex-situ (čuvanje uzoraka semena u bankama gena). Više od 130 000 uzoraka kukuruza, tj. oko 40% od ukupnog broja, nalazi se u deset najvećih banaka gena u svetu, a banka gena Instituta za kukuruz Zemun Polje (MRIZP), sa oko 6000 uzoraka je jedna od njih. Organizovano kolekcionisanje započeto je u bivšoj Jugoslaviji 1961. godine, i do danas je sakupljeno i čuva se više od 2000 uzoraka lokalnih populacija kukuruza. Predoplemenjivačke aktivnosti, koje se odnose na identifikaciju poželjnih svojstava u neadaptiranoj germplazmi u banci gena, rezultiraju u materijalu za koji se očekuje da bude uključen u oplemenjivačke programe. Uspešni primeri su LAMP, GEM i GENRES projekti. Krajem XX veka, u MRIZP banci gena, preduzete su predoplemenjivačke aktivnosti, formirane su eco-core i elite-core kolekcije, i odabrane su populacije koje su ispunile potrebne kriterijume. U prethodnoj deceniji, kolekcija banke gena korišćena je za identifikaciju izvora tolerantnosti na sušu i poboljšan kvalitet zrna. Na osnovu agronomskih osobina i opšte kombinacione sposobnosti, formirane su dve mini-core kolekcije koje su već uključene u programe oplemenjivanja.

Drought is one of the main consequences of climate change that negatively affects plant growth and development, which in turn leads to a reduction in yield. The objective of this study was to investigate the effects of the physiological responses to the drought stress of maize plants (population IP3722), obtained from seeds of different ages (originating from 2012. and 2016) and different previous experience (the seeds formed in 2012. were more exposed to drought than in 2016.). Two populations responded to drought treatment by a significant decrease of shoot fresh and dry weight, this was followed with decrease leaf area and transpiration rate. Drought tre-atments enabled induction and differentiation of chemical signals of drought (abscisic acid-ABA and xylem pH) and hydraulic signals (leaf water potential), and monitoring of their activity on stomatal conductance. The data showed that hydraulic signals have the same impact on stomatal reactions in the D2012 and D2016 treatments. They also indicated that the chemical signal of ABA works toward stomatal closure, but that the effect depends on whether it originates from the leaf or the root. Leaf-originating ABA had more effect on the closure of D2012 stomata, while root-ori-ginating ABA and pH was more active in the D2016, Suša nastaje kao posledica klimatskih promena, koja negativno utiče na rast i razvoj biljaka, a to dovodi do smanjenja prinosa. Cilj ovog rada bio je da se istraži efekat suše na fiziološke reakcije biljaka kukuruza (IP3722), koje su dobijene iz semena različite starosti (regenerisano 2012. i 2016.) i različitih prethodnih iskustava (semena koja su formirana 2012. su bila u većoj meri izložena suši nego ona iz 2016.). Suša je kod oba uzorka dovela do smanjenja sveže i suve mase nadzemnog dela biljke, što je bilo praćeno opadanjem lisne površine i stomatalne provod-ljivosti. Tretmanom suše su indukovani hemijski signali (ABA i pH) i hidraulički signal (vodni potencijal), koji su uticali na provodljivost stoma. Podaci su pokazali da hidraulički signal ima podjednak udeo na zatvaranje stoma u tretmanu D2012 i D2016. Takođe, ABA kao hemijski signal dovodi do zatvaranja stoma, ali ovaj efekat zavisi od toga da li ABA potiče iz korena ili lista. ABA poreklom iz lista je imala značajniji doprinos u zatvaranju stoma kod D2012, dok ABA poreklom iz korena i pH kod tretmana D2016.

Maize grains contain high level of carotenoids and tocopherols compared with other cereals. Among carotenoids the β-carotene has the highest activity and is considered important in breeding programs of biofortified crops. Changes in carotenoids content in the maize grain could be influence of genotype x environment interaction, or effect of existing relationship between the color of the endosperm and the presence of carotenoids. This research was performed to estimate differences in morphological traits, grain content of tocopherols (α-, β+γ-, δ-), β-carotene, lutein and zeaxantin in local and introduced populations from Maize Research Institute 'Zemun Polje' gene bank. Micronutrient content was detected by using high-performance liquid chromatography (HPLC). Coefficient of variation for morphological traits was less than 10%, except for grain yield per plant which vary about 18,6%. α-tocopherol content was in the range from 1.04-8.42 μgg-1 DW, and β-carotene content varied from 0.26 to 7.95 μgg-1 DW. δ-tocopherol was in significant correlation with number of kernels per row (r=0.700***), and β+γ-tocopherol was in significant negative correlation with plant and ear height (r=-0.601***; r=-0.591**). Correlations between morphological traits and α-tocopherol were weak and without significance. Kernel color was significantly correlated with the content of zeaxantin (r=0,590***) and β-carotene (r=0,398*). For biofortification purposes a pool of 11 landraces with increased content of both, β-carotene and α-tocopherol, will be created based on obtained results., U odnosu na druge žitarice, zrno kukuruza sadrži visok nivo karotenoida i tokoferola. Od svih karotenoida β-karoten ima najveću aktivnost i smatra se najznačajnim u biofortifikacijskim programima oplemenjivanja žitarica. Ovo istraživanje je imalo za cilj da utvrdi razlike u morfološkim svojstvima, sadržaju tokoferola (α-, β+γ-, δ-), β-karotena, luteina i zeaksantina kod lokalnih i introdukovanih populacija kukuruza iz banke gena Instituta za kukuruz 'ZemunPolje'. Sadržaj mikronutrienata je utvrđen primenom HPLC metode. Koeficijent varijacije za morfološka svojstva je bio manji od 10%, osim za prinos zrna po biljci (Cv=18,6%). Sadržaj α-tokoferola je bio u rasponu od 1,04-8,42 μg g-1 suve mase, a β-karotena od 0,26 to 7,95 μg g-1suve mase. δ-tokoferol je bio u značajnoj korelaciji sa brojem zrna u redu (r=0,700***), dok je β+γ-tokoferol bio u značajnoj negativnoj korelaciji sa visinom biljke i klipa(r=-0,601***; r=- 0,591**). Korelacije između morfoloških svojstava i α-tokoferola bile su slabe i nesignifikantne. Boja zrna je bila u značajnoj korelaciji sa sadržajem zeaksantina (r=0,590***) i β-karotena (r=0,398*). Za potrebe biofortifikacije 'pool' od 11 populacija sa povećanim sadržajem i β-karotena i α-tokoferola biće formiran na osnovu dobijenih rezultata.

Predictions of global warming point out that frequency and severity of temperature and rainfall extremes are expected to increase in the following decades. Yield stability could be achieved by improvement in future breeding based on information of cereal reproduction under changed environmental conditions. Landraces are valuable sources of beneficial alleles, e.g. tolerance to drought and improved grain yield, for introgression into adapted germplasm. Twenty-six drought tolerant maize landraces, selected among gene bank accessions and previously tested under controlled drought conditions and in temperate climate, were evaluated, at two sites and two plant densities in Zemun Polje. Since 2014 was with enormous rainfalls and flooding, morphological and agronomical traits were measured. Obtained data, together with the results from dry 2012, were plotted for principal component analysis. One local landrace and two introduced landraces, medium in maturity, were selected according to PC analysis and achieved grain yield that was stable across different climatic conditions., Procenjuje se da će u narednim decenijama, usled globalnog zagrevanja, doći do učestalije pojave ekstremnih temperatura i padavina. Ostvarivanje stabilnih prinosa u budućim programima oplemenjivanja zavisiće od informacija o mogućnostima reprodukcije useva u promenjenim uslovima spoljašnje sredine. Populacije predstavljaju dragocen izvor poželjnih alela (npr. za tolerantnost prema suši i poboljšanje prinosa) za introgresiju u adaptiranu germplazmu. Dvadeset šest populacija kukuruza, tolerantnih na sušu, odabranih iz banke gena i prethodno testiranih u uslovima kontrolisanog stresa suše, kao i u umerenom klimatu, testirane su na dva lokaliteta i u dve različite gustine u Zemun Polju. U 2014. godini koju su obeležile velike količine padavina i poplave, merena su morfološka i agronomska svojstva. Dobijeni podaci, zajedno sa podacima iz sušne 2012. godine obrađeni su PCA metodom (analiza glavnih komponenti). Jedna lokalna i dve introdukované, srednjestasne populacije, odabrane su na osnovu PC analize i ostvarenog prinosa zrna, koji je bio stabilan bez većih variranja, u različitim uslovima spoljašnje sredine.

Twenty-six maize landraces were tested in order to evaluate maize seedling performance as an index for drought tolerance in adult plants. Samples were subjected to polyethylene glycol-induced osmotic stress at the early seedling stage. Grain yield was obtained in field experiments under well-watered (OC) and a combination of drought and high plant density (HD) conditions. Osmotic stress caused a reduction in seedling growth (length, fresh and dry weight), and increase in the shoot and in particular the root proline contents in the majority of landraces, and variations in root peroxidase (POD) activity. Genotypes displaying more pronounced root growth reduction and higher proline contents exhibited decreased POD activity under osmotic stress. Direct positive correlations between the proline content and growth inhibition, and between the proline and soluble protein content were established. Correlations between the changes in POD activity and growth parameters were significant and positive, and significant but negative with the changes in the proline content. In the field, water stress led to a reduction in grain yield in all of the tested landraces. Correlations between grain yield from both experimental sets (OC and HD) and osmotic-induced changes in seedling root growth were negative, which was opposite to the highly significant and positive correlations between the changes in the seedling root proline content and yield. Also, genotypes with the highest seedling root proline content increase under osmotic stress, exhibited the highest stress tolerance index (STI) based on grain yield achieved under both field conditions. Our results indicate that lower changes in POD activity and especially an increased proline content after exposure to osmotic stress during the early seedling stage could be considered as useful indices to facilitate selection efficiency for drought tolerance in adult plants.

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.