Inheritance and Genetic Analysis of Grain Weight Per Spike in Barley

Abstract

The aim of the study was to investigate the systems of genetic control of the trait “grain weight per main spike” in spring barley in the system of diallel crosses to optimize the breeding process for yield. Six varieties of barley were used as parental forms: Condor and Omskiy naked 1 (hulless), Margret, Lun, Nutans 553, and Anna (hulled). Crosses according to the full diallelic scheme were performed in 2008 and 2009. Field experiments were carried out in the forest-steppe of Penza region in 2009 and 2010 with contrasting hydrothermal regimes. In most hybrid populations, the grain weight per spike was inherited according to the type of overdominance and complete dominance of the parent with a high value of the trait. The analysis of the combining ability by B.Griffing showed that both additive and non-additive effects were present in the control of the trait; their balance varied by years and genotypes. The correlation coefficients between the general combining ability (GCA) and the degree of the trait in parental varieties (r=0.76...0.96) indicate that the selection of pairs for crosses can be carried out on the basis of high values of grain weight per spike, especially in a dry year. Genetic analysis by B.Hayman showed the prevalence of the effects of overdominance in the control of the trait; in 2009, complementary epistasis was also registered. Overdominance and non-additive effects in the control of a trait complicates selection in early generations, which is confirmed by the differences between the values of heritability coefficients in the broad sense (H2=0.79...0.94) and in the narrow sense (h2=0.24...0.59). The largest number of dominant genes controlling the grain weight per spike was found in Margret in both years of research and Anna in the dry year. These varieties are also distinguished for the consistently positive effects of GCA and are recommended as donors of the trait for breeding