FEATURES OF WINTER RYE YIELD FORMATION IN CONTRASTING HYDROTHERMAL CONDITIONS OF THE NORTHERN MIDDLE VOLGA REGION

The goal of the study was to determine the response of winter rye varieties to humidity deficit and correlations with yield components under favorable conditions of spring- summer vegetation and under drought conditions. The study was carried out in Tatar Scientific Research Institute of Agriculture, FRC Kazan Scientific Center of RAS (Republic of Tatarstan, the north of the Middle Volga region) in contrasting hydrothermal conditions in 2020-2021. The object of the study was 11 varieties and populations of winter rye of the competitive variety trials. Principal components method with biplot visualization was used to analyze the results. It was found that the yield depended to a larger extent on the number of productive stems per unit area, grains per 1 m2, grain weight from the main spike, 1000 grains weight, hectoliter weight and plant height. These factors contributed 94,4% to the variability of the yield in the favorable year and 87% in the case of limiting the moisture content. The different contribution and unequal factor loadings of yield-forming traits to the variability of the yield in the contrasting years are shown. As a result of negative influence of weather factors in 2021, the most significant depression as compared with a favorable year showed grain yield (40.7%), 1000 grains weight (28.5%) and grain weight from the main spike (27.6%). It was revealed unequal response to moisture deficit and favorable moisture in the formation of the yield of varieties Podarok, Ogonek, Tatarskaya 1, Population 18, Population Dymchataya. Promising populations Population 19, Population 20, Population 18, and variety Tatarskaya 1 showed the highest yield according to the results of contrasting years. The correlations between economic traits of winter rye varieties under favorable conditions of spring- summer vegetation and under drought conditions were considered.