Ecological adaptability parameters of the alfalfa varietal samples according to the trait “seed productivity” in the Rostov region

Relevance. Adaptive plant breeding is considered an effective and affordable tool that allows to develop varieties that are weakly responsive to the emerging unfavorable conditions. Methodology. The current study of the alfalfa samples was carried out on the experimental plots of the ARC “Donskoy”. The objects of research were the varieties of the ARIPGR (VIR) collection (11 samples from the USA, 16 samples from Canada, 2 samples from France, 1 sample from Peru). Results. Estimation of the alfalfa varietal samples according to some ecological adaptability parameters according to the trait “seed productivity” showed that the varietal samples from this collection respond differently to the environmental changes in their cultivation. The genotypes K-32783, K-42684, K-42685, K-48773, K-48774, K-48775, K-42694, K-45119, K-45715, K-47800, K-47801, K-47802, K-47803, K-47804, K-39978 and K-42712 had bi < 1 and hardly responded to the changes in growing conditions, and they had stable, although not very high, seed productivity. There have been identified the samples K-32783, K-42694, K-47801 and K-42712 that demonstrated their resistance to stress conditions. The samples K-50545 and K-50561 turned out to be genetically flexible, their “compensatory ability” better corresponded to the environmental factors. The genotypes K-43272, K-50545 and K-50561 were characterized with higher coefficient (σ d 2 ) of the productivity stability in comparison with the standard variety.