Identification of chromosome regions determining kernel high oil content in maize (Zea mays L.) Synthetic populations

Chromosome regions determining kernel high oil content were identified by RFLP analysis of individual plants from C0 and C9 selection cycles of two maize synthetic populations -DS7u and YuSSSu. Identification of chromosome regions was done with informative RFLP markers (that were identified with BSA earlier) using a single plant approach - analysis of individual plants. This analysis revealed the number of plants carrying alleles that endured frequency alterations during selection process. Statistical analysis (χ2 test) revealed chromosome regions that comprise putative QTLs affecting expression of kernel high oil content of analyzed maize populations. Four regions on chromosomes 1, 6, 7 and 8 were identified in both DS7u and YuSSSu populations. Additional four regions on chromosome 4, 9 and 10 were detected only in DS7u population

Sadržaj proteina i triptofana u zrnu hibrida kukuruza

In this work, proteins and tryptophan content were analyzed in kernels of semi-flint, semi-dent, dent and specialty ZP maize hybrids. Protein content, as well as protein fraction, differed significantly among the analyzed maize genotypes. Globulin was the lowest fraction in kernels of all maize hybrids (6.69-11.03% of total protein). The content of albumin was the highest in sweet hybrids ZP 441su and ZP 461su i.e. 20.27% and 19.76% of total protein, respectively. α-Zein and G-3 glutelin were dominant protein fractions in all maize genotypes. The highest content of α-zein and G-3 glutelin was in the kernels of popping maize hybrid ZP 611k, i.e. 29.25 and 25.71% of total protein, respectively. All hybrids could be classified according to the tryptophan content in three groups - over 0.08% (sweet and waxy hybrids), from 0.06 to 0.07% (three standard dent hybrids, one semi-flint and two semident hybrid) and from 0.05 to 0.06% (two semi-flint, one semi-dent hybrids and popping).U ovom radu ispitivan je sadržaj rastvorljivih proteina i triptofana u zrnu polutvrdunaca, poluzubana, zubana i specifičnih ZP hibrida kukuruza. Sadržaj ukupnih proteina, kao i sadržaj rastvorljivih proteinskih frakcija se statistički razlikovao između analiziranih genotipova kukuruza. Globulin je bio najmanjie zastupljena frakcija u kukuruznom zrnu (6.69-11.03% od ukupnih proteina). Sadržaj albuminske frakcije u zrnu hibrida šećeraca ZP 441su i ZP 461su iznosio je 20.27% i 19.76% od ukupnih proteina, dok je u zrnu ostalih hibrida bio značajno niži. α-zein i G3-glutelin bile su dominantne frakcije u zrnu svih ispitivanih genotipova kukuruza. Najviši sadržaj α-zeina i G3-glutelina bio je u zrnu kukuruza kokičara ZP 611k i iznosio je 29.25% i 25.71% od ukupnih proteina. Prema sadržaju triptofana svi analizirani hibridi mogu se podeliti u tri grupe: preko 0.08% (šećerci i voksi hibridi - ZP 441su, ZP 461su i ZP 704wx), od 0.06 do 0.07% (tri standardna zubana - ZP 434, ZP 544, ZP 688, poluzubani - ZP 643, ZP 717 i polutvrdunac ZP Prado), od 0.05 do 0.06% (dva polutvrdunca - ZP 209, ZP 745, jedan poluzuban i kokičar - ZP 505, ZP 611k). PR Projekat Ministarstva nauke Republike Srbije, br. TR-20039

A model of a successful utilization of a high genetic potential of maize yield

The principle of a system, defined as a ZP system, implying corresponding relationship among research, seed production and seed marketing, is that each segment within the system has its tasks and responsibilities, as well as, a clear interest. This system was established at the Maize Research Institute, Zemun Polje, almost half a century ago. The crucial characteristic is that this system encompasses obtained results of scientific accomplishments (patent - a released hybrid), optimal utilisation of the environmental conditions, facilities for seed drying, processing and packing, staff and transport capacities. The ZP system provides the economic interest of all participants in studies and the maize seed production. The fundamental base of the quality seed production within the ZP system is a multidisciplinary programme on maize breeding, as well as, 535 released hybrids with standard and specific traits. According to regulations in foreign countries, approximately 100 ZP maize hybrids have been released abroad. Agroecological conditions in Serbia are favorable for the development of the best genotypes and the production of basic and certified maize seed. There 10 processing plants that apply recent technologies in the maize seed processing procedure. Several generations of experts have been trained and gained experience within the maize seed production. Three seed testing laboratories have been accredited by the International Seed Testing Association. According to regulations in Serbia, monitoring of seed production under field conditions, and further on, during the processing practice is done only by designate authorities. This study presents one of successful systems of the seed production organization applicable in countries with similar conditions

Primena molekularnih markera u analizi sadržaja ulja u zrnu grupnih uzoraka sintetičkih populacija kukuruza (Zea mays L.)

RFLP loci, potential indicators of kernel high oil content, were identified using bulk segregant analysis (BSA) approach, i.e. bulked samples derived from C0 and C9 selection cycles of two maize synthetic populations - DS7u and YuSSSu. The kernel oil content was determined by the NMR spectroscopy. The genome analysis of bulked samples was carried out with 57 RFLP markers (UMC core set). On the basis of allele frequency differences between cycles of selection, informative RFLP markers (potentially closely linked to QTLs regulating high oil content in maize) were identified. Four common RFLP loci were identified in both DS7u and YuSSSu populations. Additional four RFLPs were identified in DS7u population.RFLP lokusi, potencijalni indikatori povećanog sadržaja ulja u zrnu, identifikovani su analizom grupnih uzoraka (Bulk Segregant Analysis - BSA) C0 i C9 ciklusa selekcije dve domaće sintetičke populacije kukuruza - DS7u i YuSSSu. Sadržaj ulja u zrnu biljaka ispitivanih ciklusa selekcije obe populacije utvrđen je NMR spektroskopijom. Analiza genoma grupnih uzoraka početnog (C0) i krajnjeg (C9) ciklusa selekcije DS7u i YuSSSu urađena je pomoću 57 RFLP markera UMC core set. Na osnovu promena u frekvenciji alela u grupnim uzorcima u toku procesa selekcije analiziranih populacija utvrđene su informativne probe - probe potencijalno blisko vezane za QTL uključene u kontrolu povećanog sadržaja ulja u zrnu kukuruza. Identifikovana su četiri zajednička RFLP lokusa u obe analizirane populacije, s tim što je u populaciji DS7u identifikovano još četiri RFLP lokusa potencijalnih indikatora povećanog sadržaja ulja u zrnu kukuruza

Poboljšani fotositetično-fluorescentni metod i njegova primena u oplemenjivanju i semenarstvu kukuruza

The application of the improved non-invasive photosynthetic-fluorescence method in maize breeding and seed production was observed in order to assess the resistance and adaptability of maize inbred lines to higher and high temperatures, as well as to drought. The studies were carried out with two maize inbred lines (ZPPL 115 and A 671). The thermal characteristics of the photosynthetic apparatus of the investigated maize inbred lines were determined as follows: temperature dependency range from 25 to 60oC, critical temperatures at which phase transitions take place in the thylakoid membrane, causing significant structural and functional changes in the photosynthetic apparatus of the investigated inbred lines, activation energies (Ea, kJ/mol) were calculated along the straight lines before and after the occurrence of the critical temperature. The activation energy (Ea) is a measure of the intensity of recombining responses to chlorophyll DF, and total changes in the structure and functioning of the thylakoid membranes. The results obtained and presented parameters of total photosynthetic and thermal processes of chlorophyll DF may contribute to a more accurate characterisation of maize inbred lines in respect to their resistance and adaptability to temperatures and drought. Consecutively, this can lead to a quicker and more rational improvement maize breeding and seed production.Poboljšani neinvazivni fotosintetično-fluorescentni metod kandiduje se za primenu u oplemenjivanju i semenarstvu radi utvrđivanja ocene samooplodnih linija kukuruza na plastičnost, tolerantnost, otpornost i adaptivnost prema višim i visokim temperaturama, kao i prema suši. Utvrđene su termalne karakteristike fotosintetičnog aparata proučavanih samooplodnih linija kukuruza, i to: određena je temperaturna zavisnost u opsegu od 25 do 60oC, otkrivene su kritične temperature na kojima dolazi do faznih transformacija u tilakoidnoj membrani, a time i do značajnih strukturnih i funkcionalnih promena u fotosintetičnom aparatu ispitivanih samooplodnih linija kukuruza, obračunate su energije aktivacije (Ea, kJ/mol) duž pravih linija pre i posle pojavljivanja kritične temperature. Energija aktivacije (Ea) je mera nastajanja rekombinacionih reakcija povezanih sa uspostavljanjem ZF hlorofila, a time i ukupnih promena u strukturi i funkciji tilakodinih membrana. Ostvareni rezultati i diskusija izloženih parametara ukupnih fotosintetično-termalnih procesa ZF hlorofila mogu doprineti egzaktnijem karakterisanju ispitivanih samooplodnih linija kukuruza u odnosu na njihovu plastičnost, tolerantnost, otpornost i adaptivnost prema temperaturi i suši, što samim tim i doprinosi bržem i racionalnijem unapređenju procesa selekcije i produktivne semenske proizvodnje