Plus-Transgression in Winter Wheat Breeding on Frost Resistance and Productivity

Аннотация

Abstract—The results of breeding using transgressive variability during 1985–2018 on the Don are presented. The location is a chernozem steppe with frequent frosts and insufficient and unstable moistening over the years. The technology of breeding was common: the pedigree and bulk methods were used. When laying a breeding nursery, the following approaches were new: sowing up to 45 000 untreated ears of a designed planter (to eliminate weeding during threshing ears), determining the frost resistance of plants that have been hardened in the field in bundles placed in plastic bags in low temperatures, and determining their viability for 3 days after freezing by the Don method. A large layer of studies (more than 11 000 populations) was analyzed, starting with the F₁ population and ending with the completion of formation for each one. It is confirmed that transgression that is the result of the recombination is observed in populations whose parents do not have extreme expression of the trait. It is established that populations should be heterogeneous with long-term formation. This happens when parents have very few common genes and when there is no restriction on recombination due to too large differences in components. With the presence of overdominance in F₁ in many studied populations, it is possible to predict the appearance of transgressions (for frost-resistance and productivity in our case) with an average frequency of 0.25-4.36%. They are also possible, but an order of magnitude less than when overdominated, with the incomplete and complete dominance of the trait of the best parent, the excess of parents in F₂ on average for the population, or with an intermediate inheritance in F₂. This should be accompanied by large volumes of studying the breeding material in the first stages and the presence of various stresses. Of the 38 varieties that were included in the State Register of Russia, 29 were transgressive recombinants for winter hardiness and productivity. They all withstand –18°С on the tillering knot.