VARIABILITY AND GENETIC CONTROL OF WINTER WHEAT RESISTANCE TO WINTER

Abstract

Winterhardiness is regarded as a parameter controlled by the activities performed by a large number of genes. In diallel crossbreeding, a researcher has complete combinations of genes that parental varieties possess. The paper analyses additivity and dominance of the crossbreeding population. It allows to assess the contribution made by the main types of gene interactions to parameter expression by decomposing the genotypic variant into a general and specific combination ability. The research aims at exploring the variability of winterhardiness of soft winter wheat and determining the system of genetic determination of this indicator. The experiment was conducted in the experimental field of Siberian Research Institute of Agriculture in Omsk in 2013-2014. The varieties and hybrids of F1 had triple sowing. The area of plant nutrition was 10 x 20 (cm2). The coulisse fallow was forecrop. The authors explored six samples of soft winter wheat and 30 F1 diallel hybrids. They observed reliable differences among genotypes according to “winterhardiness” parameter (P ≤ 0.05). Variability of this parameter is specified by meteorological conditions (95.07%) and determined by means of two-factor dispersion analysis. The authors used Heiman’s figures in order to evaluate and explore the genetic features of winter wheat winterhardiness (relationship between Wr and Vr - covariance and variant) and genetic parameters. The OCS effect was high (P<0.05), therefore, additive genes played an important role in the features heritability. The effect of SCS was high and reliable as well. Positive correlation values (r (2013) = 0.81 and (r (2014) = 0.19) among the average parental values (P) and (Wr + Vr) indicate that their dominance is indirect and recessive genes may increase winterhardiness. The average dominance parameter was higher than 1. This proves the great contribution of nonadditive genes to possessing winterhardiness. Selection of unique genotypes with strong winterhardiness is supposed to occur in older generations of hybrids (F4 - F6). The Zhemchuzhina Povolzhya variety can become a donor in stressful conditions of overwintering (OCS effect is 13.33), in favorable conditions – Fantasia variety (OCS=12.69).