Current Approaches in Modeling of Barley Cultivars for the Volga-Vyatka Region

Models of cultivars of agricultural crops are created for certain agro-climatic conditions. The aim of the research is to supplement the existing models of two- and multirow spring barley cultivars adaptive to the soil-climatic conditions of the Volga-Vyatka region with new features and properties for their more effective implementation. Studies were carried out using extensive, statistically processed data from collection nurseries and competitive variety tests for 2003–2019. Cultivars having longer growing periods were characterized by high yields. Under the conditions of the region, barley cultivars formed yields due to a different combination of elements of the yield structure. Thus, a significant contribution to yields was made by the spike productivity and the thousand kernel weight; however, in multirow barley, the dependence of productivity on these traits was more significant (r = 0.61 and 0.78, respectively) than in two-row barley (r = 0.40 and 0.42). In all cultivars, the density of plants per unit area for harvesting should not exceed 350–400 pieces per m². The optimal ratio of the count of grains per spike and the thousand kernel weight in two-row cultivars is 1.0 : 2.3 and that in multirow cultivars 1 : 1. Lodging-resistant cultivars of both the subspecies were characterized by a large number of nodular roots and a ratio of grain mass to straw of 1.0 : 1.0 or 1.1 : 1.0, depending on the growing conditions. To select forms with high adaptive properties, it is necessary to use the root length index (RLI), which characterizes the growth of the root system under stress, and the RSR index, which reflects the distribution of plastic substances whose values should approach 100%, and changes in physiological processes in plants under stress should be minimal (the integral index of resistance). The statistically significant association (at p ≤ 0.05) of chlorophyll a (r = 0.64), chlorophyll b (r = 0.58), and carotenoids (r = 0.60) in the second last leaf with the yield capacity also makes these indicators promising for use in barley breeding.