Effect of meteorological factors on the seed yield of alfalfa in the droughty Volga Region

Over 25 years, the seed yield of two alfalfa varieties, despite sharp fluctuations, increased significantly, especially from 2005 to 2013 (by 3.9 times in Artemida, by 4.8 times in Eruslanka). The latter period of investigation was characterized by higher values of the average air temperature (1.1°C), as well as lower relative humidity (6.3%) and amount of precipitation during 2 years of vegetation (82.0 mm). The seed yield of both cultivars was related positively to the average air temperature and negative to the rainfall and relative humidity. It was suggested that improvement of the conditions for breeding of pollinators and visitation of flowering plants by them play a crucial role for increase in the seed production of alfalfa.