Genetic value of maize lines in terms of the reaction norm to phenotypic conditions in F1 hybrids

Abstract

The problem of resistance of maize hybrids to pathogens requires a comprehensive approach. In breeding for heterosis, the priority line of research is systemic analysis of data of trials of hybrids for a given trait.The need for in-depth knowledge of methodological differences between discrete and continuous variability of resistance to pathogens urged the authors to develop methods for assessment of the genetic value of maize lines in terms of the reaction norm to the phenotypic environment of F1 hybrids originated from these lines. They need a variety of specific methods for assessment of lines and hybrids. The interaction of genomes of parental forms in a heterozygous organism was determined by phenotypic and breeding values.The aim and tasks of the study. The purpose of the work was calculation of the index of donor characteristics (IDC), realized by particular female lines in a particular hybrid.Material and methods. The study was conducted in 2000-2010 in the Laboratory of Plant Immunity to Diseases and Pests and the Laboratory of Genetics of the Plant Production Institute nd. a VYa Yuryev of NAAS. The study material was 500 maize lines. Three lines- testers UKh 126, GK 26 and T 22 were used.Results and discussion. The efficiency of two algorithms of the systemic analysis of was investigated. Of them, the comparative evaluation of lines and hybrids in terms of specifics of manifestation of systemic properties was more informative. The assessment of genetic value hybrids was less informative, but necessary, if it was impossible to evaluate parental lines.The expediency of the breeding value index (BVI) and the index of donor characteristics (IDC) of female lines in a particular hybrid providing comparative characterization of lines in terms of the trait expression was proved.The specificity of reaction of a female line to genotypic conditions was established: high level (line-tester GK 26), low level (line-tester Ukh 126), intermediate level (line-tester T-22).The IDC values for female lines by resistance to Fusarium pathogens were determined (IDC <1.22, bi <1), which contributes to obtainment of hybrids with high field resistance to the pathogen.Conclusions. Five types of femal lines of maize were distinguished by the genetic value of breeding for resistance to Fusarium. Lines of types II and IV (type 2 - 300, 302, 305, 306, 314, 316, 325, 330, 335, Type 4 - 303, 304, 309, 311, 312, 313, 326, 337, 339) were considered as valuable for heterosis breeding in programs on creation of maize hybrids with high productivity and genetic protection against Fusarium.