Abstract
The international program of Kazakhstan–Siberian Network on Spring Bread Wheat Improvement (KASIB), established with the assistance of CIMMYT in 2000, is aimed at the search for new genetic sources of agronomic traits. In 2023–2025, 48 varieties of spring bread wheat of the KASIB-24 nursery, developed at 15 research and breeding institutions of Russia and Kazakhstan, were studied; they were genotyped using 14 PCR markers according to standard protocols. The research aimed to assess the genotypic diversity of promising varieties and lines of spring bread wheat of the KASIB-24 nursery and to reveal the effects of certain genes on yield and agronomically important traits in the ecological zones of Western Siberia and Ural. Genetic differentiation of the accessions of the KASIB-24 nursery using 14 DNA markers identified three clusters, without a clear grouping of the genotypes according to their affiliation with breeding programs. Analysis of the allelic variant associations with agronomically valuable traits revealed, in Omsk, a statistically significant effect (p < 0.05) of the dominant Vrn-A1 allele on the reduction of period to heading and maturity (by an average of 3 days), as well as a reduction in plant height (–3.9…–9.43 cm). In Tyumen, genotypes with Vp-B1c haplotype were characterized by earlier heading and maturation (88–91 days). In 2023, in Omsk under severe drought, plants with the DRO-5A/Hap-C allelic variant had a higher thousand kernel weight (+14.5 g). Accessions carrying favorable haplotypes at most loci were identified and are recommended as genetic sources of agronomically valuable traits for hybridization programs.