The duration of the growing season and its impact on the productivity and quality of barley grain in the Middle Volga region

The analysis of the values of hydrothermal coefficients (GTC) by year, by development phases and during the growing season of barley plants shows that the total duration of the growing season increased with decreasing air temperature and heavy precipitation, and, conversely, decreased during dry years. High values of shoot weight and 1000 grains, yields were obtained in the favorable years of the study – 2022 and 2023 compared with the unfavorable ones 2021 and 2024, the exceedances were 2.9; 1.2 and 1.6 times, or 34.0, 14.4 and 38.2%, respectively. Over the years, the values of plant height, the amount of sugars and the starch content have shown that these signs are slightly variable and they have changed slightly by 1.1 times or by 12.6, 8.8 and 4.3%, respectively. The lowest protein accumulation in grain turned out to be the values of 10.7 and 11.1%, which were obtained in 2022 and 2023, the most favorable, and in dry years – high 12.1 and 12.5%, the change was 1.2 times or 14,4%. A correlation analysis of the data obtained was carried out, and a reliable relationship between grain yield, weight of 1000 grains, protein content, amount of sugars and starch from the duration of plant development phases and the growing season was established at a 1% significance level. For yield indicators, the mass of 1000 grains, and the phases of plant development are positive, but they differ in closeness, weak at the beginning of the growing season, and then increase in full ripeness to significant or high. For the protein content, the sum of sugars and starch, the coefficients are defined as the inverse in the initial phases of plant development, then when entering the tube-full ripeness, a linear positive relationship is traced, which tends to increase from mild to moderate to high.