Variability and heritability of yield components in maize populations with exotic germplasm

Abstract

The investigations included mean values, genetic and phenotypic variability, heritability and genetic and phenotypic coefficients, variability of yield components in the original maize population with 25% of the exotic germplasm incorporated and also, in the population after three and five cycles of gene recombining. The two-replicate trial was set up according to the nested design method in two locations in order to investigate effects of different cycles of gene recombination. According to the obtained results, it was concluded that the mean values had increased more significantly to the third than from the third to the fifth cycle of free hybridisation. The additional gene recombination affected the insignificant decrease of the genetic and phenotypic variability of traits. Estimated values of heritability were high and significant for yield, which indicated that they were mostly determined by the additive variance. The additional cycles of gene recombination caused the decrease of heritability and the coefficient of genetic and phenotypic variability. Greater mean values of yield components after the third and the fifth gene recombination cycles, relating to the original population, indicate to a positive effect of the additional recombination cycles on the increase of a gene frequency in case of desirable traits, and the frequency of the more yielding genotypes.

Proučavanjem je obuhvaćena originalna populacija kukuruza sa 25% egzotične germplazme (1601/5 x ZPL913)F2R0 i populacije nakon tri (1601/5 x ZPL913) F2R3 i pet (1601/5 x ZPL913)F2R5 ciklusa rekombinovanja gena. Ogled sa S1 potomstvom je postavljen po metodu nested dizajna u dva ponavljanja na dve lokacije u toku dve godine (2005 i 2006). Prosečne vrednosti za sva ispitivana svojstva osim sadržaja vlage pri berbi su se povećavale sa brojem ciklusa rekombinacija. Različiti agroekološki uslovi, genotipovi, interakcija familija x lokacija 1 i familija x lokacija 2 uticali su značajno na varijabilnost svih ispitivanih svojstava za populacije. Genetičke i fenotipske varijanse za sva ispitivana svojstva osim mase 1000 zrna su se smanjivale pod uticajem broja ciklusa rekombinacija. Značajno smanjenje nije bilo samo za dužinu klipa, što je posebno značajno za praktično oplemenjivanje. Genetičke varijanse su dovoljno visoke da omoguće uspešno oplemenjivanje. Slično se dešavalo i sa koeficijentima heritabilnosti.