COMBINATIVE ABILITY OF SOFT SPRING WHEAT BY GRAIN WEIGHT IN TOP CROSS CROSSES

The purpose of research is to analyze the general and specific combining ability of soft spring wheat based on the trait “grain weight per spike” in the conditions of the Priob forest-steppe of the Altai Region. The experiment was conducted in 2020–2021 using pure fallow on the experimental field of the Federal Altai Scientific Center for Agrobiotechnology, located in the Priob forest-steppe of the Altai Region. The work studied the combinative ability of varieties and lines of soft spring wheat for the trait “grain weight per main spike” according to a topcrossing scheme consisting of 13 maternal and 3 paternal forms. The weather conditions during the years of the experiment are characterized. It has been established that the level of manifestation and the nature of inheritance of the trait under consideration, as well as the effects of general (GCA) and specific (SCA) combinative ability, largely depend on environmental conditions and the analyzed generation of hybrids (F1 and F2). The dominant contribution to the total dispersion of spike grain weight is made by year conditions (97.8 %), followed by genotypic characteristics (2.1 %) and their general interaction (0.1 %). The leading role in the system of genetic control of a trait belongs to genes with an additive type of action, with a small contribution from non-additive gene effects. The varieties and lines of test crosses differed significantly in the analyzed trait. On average, over 2 years of research, the following varieties differed in higher spike grain weight among maternal forms: Omskaya 42, Lutescens 186/04-6 and Lutescens 6/04-4 (with values from 1.45 to 1.95 g), and among paternal forms – Lider 80 (with values from 1.31 to 2.03 g). Valuable combinations of crosses with high expression of the studied trait have been selected, which are promising both in terms of selection of the desired genotypes in early generations of hybrids, and in terms of direct use in recurrent selection when creating new commercial varieties.