Search

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.

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.

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.

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.

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.

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.

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.