Ecological adaptability of Alfalfa in a competitive variety testing nursery

Purpose. Assessment of the ecological adaptability of promising alfalfa breeding samples under conditions of increased soil acidity by determining its components – the regression coefficient and the stability variance. Methods. Field (keeping phenological observations and records), laboratory (recording dry matter and seed yield), mathematical and statistical (objective assessment of the obtained experimental data). Results. The coefficient of ecological plasticity (bi) varied in the studied samples from -0.24 to 2.29. The value of bi greater than one was found in 15 samples, but the level of productivity in terms of dry matter yield in some of them turned out to be significantly lower than that of the standard Sinyukha variety. It should be noted that the samples exceeded the standard variety in terms of feed productivity, but reacted little to changes in growing conditions (bi>1), was found in 15 samples, 11 of which exceeded the standard variety Sinyukha in seed yield. Samples with a negative value of bi were identified, which formed their maximum possible seed productivity in an unfavorable year for this trait, and in the best year there was a decrease in seed yield. Opposite values of Si2 were found: for feed productivity they were 0.2-235.0 and for seed productivity – 0-0.09, which indicates the complexity of alfalfa breeding for a combination of these traits. Conclusions. According to the results of the assessment of the regression coefficient and the variance of stability in conditions of increased soil acidity, samples with a relatively high response to improved growing conditions and an increased level of feed and seed productivity were identified.