Calculation of parameters of ecological plasticity and stability of oil sunflower varieties bred in VNIIMK

In 2016-2019 we studied ecological plasticity and stability by yield of five oil sunflower varieties. Estimation was conducted by two different methods that allow studying in details sunflower varieties by this trait. Calculation made due to S.A. Eberhart and B.A. Rusell's method that all studied genotypes possess high ecological plasticity (coefficient of linear regression > 1). The variety Master appeared to be the most plastic (bi = 2.0). The varieties Skormas and SUR (С. 855) are the most homeostatic; their mean-squared deviation coefficients are 11.9 and 14.1, respectively. When cultivation conditions are worsened technological qualities of these varieties will be kept without any significant changes. Studying of parameters of adaptability due to R.A. Udachin's method showed the variety Skormas is stable one, having a coefficient of resistance of stability index (R) equal to 42.9%. Less stable are the following varieties: Umnik (coefficient 25.7%), R-453 (Rodnik) - 1.9%; С. 855 -33.2%. Calculations for the sunflower variety Master appeared to be statistically unreliable. According to our calculation of a parameter of ecological plasticity, the most responsive on improvement of cultivation conditions is the variety Master, having an intensity indicator (I) equal to 20.1%. The variety Skormas with a coefficient I = 9.7% is less plastic in a range of the studied genotypes.