Impact of cytoplasmic male sterility and xenia on grain yield and agronomic traits of maize

Citoplazmatična muška sterilnost (CMS) odavno se koristi u proizvodnjihibridnog semena kukuruza, jer povećava kvalitet, a pritom smanjuje troškoveproizvodnje. Ksenija predstavlja efekat stranog oprašivača na zrno majčinskoggenotipa u godini oprašivanja. Kombinovani uticaj CMS i ksenija nazvan je Plushibridefekat, a ideja je da se u smeši gaji 80% sterilnog hibrida kao majke i 20%drugog fertilnog hibrida, kao oca. Mnogi autori su dobili značajno povećanjeprinosa u ovakvom sistemu proizvodnje, bez pogoršanja kvaliteta zrna.Cilj istraživanja bio je da se u našim uslovima i na domaćim hibridima ispitapojedinačni i kombinovani uticaj citoplazmatične muške sterilnosti i ksenija nanajvažnije osobine kukuruza i mogućnost uvođenja ovakvog sistema gajenja ukomercijalnu proizvodnju u Srbiji.Ogled je bio postavljen po potpuno slučajnom blok (RCB) split-split ploteksperimentalnom dizajnu u tri ponavljanja u Zemun Polju od 2009. do 2011.godine. Kao majke su se koristili sterilne (CMS-S tip) i fertilne verzije hibrida ZP 1 iZP 2, dok su očevi bili hibridi ZP 1ft, ZP 2ft, ZP 3ft, ZP 4ft i ZP 5ft. Ispitivan jepojedinačni, kao i kombinovani uticaj CMS i ksenija na najbitnije osobine kukuruza.Takođe, pomoću SSR markera utvrđena je genetička distanca između korišćenihgenotipova, da bi se našla veza između distance i efekta ksenija u Plus-hibridkombinaciji.Samo kod jednog CMS hibrida, ZP 2st, je došlo do neznačajnog povećanjaprinosa zrna (0,45 t/ha), kod kog je došlo i do značajnog povećanja težine zrna ibroja zrna po jedinici površine. Slab odgovor genotipova na sterilnost objašnjavase time što je korišćen CMS-S tip, kod koga pozitivan efekat sterilnosti ne dolazi doizražaja kao kod ostala dva tipa. CMS je uticala na značajno povećanje sadržaja uljau zrnu kod ZP 2 (0,21%). Infekcija zrna sa Fusarium verticillioides bila je veća kodoba sterilna hibrida, dok je sadržaj mikotoksina specifičnog za ovu vrstu gljive,..Because it increases quality and reduces costs at the same time, cytoplasmicmale sterility (CMS) has been used in maize hybrid seed production since long ago.Xenia is the effect of foreign pollinator on the kernel of maternal genotype in theyear of crossing. The combined effect of CMS and xenia is referred to as a Plushybrideffect and the idea is to grow in mixture 80% of one sterile hybrid asmother and 20% of the other fertile hybrid as father. Many authors got significantincrease in grain yield in this production system, without grain qualitydeterioration.The aim of the research was to examine individual and combined effect ofcytoplasmic male sterility and xenia on the most important maize traits ofdomestic hybrids, in our environment, as well as the possibility of introduction ofthis kind of growing system in the commercial production in Serbia.The three-replicate trial was carried out according to randomized completeblock (RCB) split-split plot design in Zemun Polje during 2009, 2010 i 2011. Sterile(CMS-S type) and fertile versions of ZP 1 and ZP 2 hybrids were used as mothers,while ZP 1ft, ZP 2ft, ZP 3ft, ZP 4ft and ZP 5ft hybrids were fathers. Individual andcombined effects of CMS and xenia on the most important maize traits wereexamined. Also, genetic distance between used genotypes was determined usingSSR markers, to find the relationship between distance and xenia effect in a Plushybridcombination.Only one CMS hybrid, ZP 2st, had insignificant increase in grain yield (0,45t/ha), and at the same time significant increase in kernel weight and kernelnumber per unit area. Weak response of the genotypes to sterility is explained withthe use of CMS-S type, in which positive effect of sterility doesn’t come to the foreas in the other two types. CMS had significant impact on kernel oil content increasein ZP 2 (0,21%). Kernel infection with Fusarium verticillioides was higher for bothsterile hybrids, while kernel content of mycotoxin fumonisin B1, specific for this fungi species, in ZP 1st was significantly lower, and in ZP 2st insignificantly higherthen in fertile analogue..