Dynamics of alfalfa seed hardness change depending on the seed storage time

A significant part of perennial legumes seeds, including alfalfa, after ripening, has a seed coat nonpermeable for water and air, and therefore they do not germinate immediately after sowing. This property is called seed hardness. The purpose of our research was to study seed hardness of the alfalfa samples in the collection of the FSBSI “ARC “Donskoy” depending on the seed storage time. The seed hardness of the studied varieties after 1 month of storage ranged from 31 to 74% on average for two years. The varieties “Sonora 76” (the USA) and “Stavropolskaya 430” (Russia) possessed the highest value of the studied trait (62% and 74%, respectively). The seed hardness of the standard variety “Rostovskaya 90” was 49.5%. After 6 months of storage, the percentage of seed hardness in all studied varieties significantly decreased. The studied indicator of the standard variety “Rostovskaya 90” decreased to 24%. The varieties “Smuglyanka” (Ukraine), “Zvezdochka” (Russia), “Veko” (Canada), “Admiral” (Canada), “Verta+” (Canada), “AZNIHI-5” (Azerbaijan), “Tashkentskaya 1” (Uzbekistan), “Karlygash” (Kazakhstan) with the indicators from 7% to 13% had a significantly lower percentage of seed hardness compared with the standard variety. The varieties “Sonora 76” (USA) and “Stavropolskaya 430” (Russia), with seed hardness of 38.5% and 49%, respectively, significantly exceeded the standard variety “Rostovskaya 90”. After 12 months of storage, seed hardness of the studied varieties ranged from 4 to 22.5%. The indicator for this trait of the variety, taken as a standard was 16.5%. A significantly lower percentage of seed hardness (from 3% to 10%) was in 12 studied varieties, the lowest indicator was shown by the variety “Zvezdochka” (Russia). The two varieties “Sonora 76” (USA) and “Stavropolskaya 430” (Russia) showed a significant excess with indicators of 21.5% and 22.5%, respectively.