Features of transgressive breeding of winter wheat under drought conditions
The purpose of the research was to clarify the methodology for creating genetic variability during drought and to study the features of the manifestation of transgressive forms of common winter wheat under such conditions. The work was performed in 2000-2020 in the steppe chernozem zone of the Rostov region. The breeding was conducted according to the generally accepted scheme using pedigree and bulk methods. The annual amount of processed material was 35-40thousand genotypes. The main marker for productivity was the mass of grain per plant and per unit area. The standard was Don 107 variety. Populations with trait transgressions with a degree of heterogeneity of up to 13-20% were obtained when parents with the smallest number of common genes controlling the main traits from different ecological-geographical regions were involved in hybridization. We bred populations with long-term morphogenesis (5-8 years). As a result of coadaptation, this led to a wide range of the release of recombinants, which were superior to their parents in terms of many properties. The duration of recombination for each population depended on the degree of heterogeneity of the initial forms of crossing and the pressure of environmental stressors. In combinations created with the participation of forms adapted to local conditions, transgressive families were isolated already in F2-F5. On their basis, varieties Paphos, Boyarynya, Bohema, and Mirabel20 were bred. In hybrid populations with complex stepwise hybridization, transgressive recombinants appeared mainly in older generations (Donmira, Akapella, and Donskaya Lira varieties as well as lines 978/16and 1206/19). During droughts, in contrast to favourable years, 56-68% of F1 hybrids often exhibited overdominance or incomplete dominance by a number of traits. However, when reseeding in F2, this was confirmed on average in 20% of combinations. The rest of the variability was of a modification nature. Other features of recombination were the same as in favourable years.