Promising Populations of Alfalfa (Medicago varia Martyn.) for Variety Change under Climatic Conditions of the Middle Volga

The research was performed to identify the most promising populations of alfalfa ( Medicago varia Martyn.) for their use in variety change. The work was performed under the conditions of the southern forest-steppe of the Middle Volga region in 2018–2021. The material for the study was represented by five promising populations of alfalfa. The released variety Izumruda was taken as the standard. The soil of the experimental plot was represented by typical medium-humus heavy loamy chernozem with the humus content of 5.2% in the plow layer; the content of mobile potassium and phosphorus (according to Kirsanov) at the level of 292 and 156 mg/kg of soil, respectively; the amount of easily hydrolyzable nitrogen of 116–132 mg/kg of soil, and pH of salt extract equal to 6.9–7.2. The seeding rate was 15 kg/ha. The largest total mean yield of green mass for the years of research was provided by samples Populyatsiya 24 (39.5 t/ha), Temno-zelenaya (39.9 t/ha), and Populyatsiya 13 (40.2 t/ha), which was by 11.0–12.9% higher than the yield of standard variety Izumruda. The production of dry matter in total of two cuttings was the highest for the varieties Populyatsiya 4 (9.4 t/ha), Temno-zelenaya (9.5 t/ha), and Populyatsiya 13 (10.2 t/ha), which exceeded the standard by 11.9–21.4%. The high content of protein and carotene was typical for the varieties Temno-zelenaya (16.74% and 115 mg per 1 kg of feed, respectively) and Populyatsiya 13 (16.62% and 110 mg per 1 kg of feed, respectively), and the protein content was the highest (16.77%) for Populyatsiya 24.