Environmental plasticity and stability of winter rapeseed varieties in conditions of the central zone of the Krasnodar region

Development of new rapeseed genotypes must be based on evaluation of parameters of environmental plasticity and stability. The purpose of the research is comparative characteristic of winter rapeseed varieties bred at the V.S. Pustovoit All-Russian Research Institute of Oil crops (VNIIMK) by calculated statistic parameters of adaptability, environmental plasticity, stability, resistance to stress factors and genetic flexibility in conditions of the central zone of the Krasnodar region in the different years. We studied varieties Elvis, Loris, Sarmat, Selegor, VN-40173 (Olivin) and three promising samples VN-38630, VN-40143, and VN-912. Indicators of environmental plas ticity and stability were calculated using seed yields of winter rapeseed varieties for six years by S.A. Eberhart & W.A. Rassell's method as revised by V.A. Zykin. To calculate a coefficient of linear regression we determined environment indexes characterizing variability of variety cultivation conditions. Resistance to stress factors and genetic flexibility we determined due to A.A. Rossille & J. Hamblin's equation as expounded by А.А. Goncharenko. Search of potential productivity and adaptability was conducted by L.A. Zhivotkova's method. The most favorable conditions for growth and development of winter rapeseed were formed in 2016, when the average yield of varieties was 5.13 t per ha, acceptable ones -in 2014 (4.21 t per ha). Conditions in 2017 and 2019 were characterized as non-satisfactory as environmental index was negative, average yield - 3.65 and 3.64 t per ha, respectively. Comparative analysis of varieties and samples of winter rapeseed of VNIIMK breeding by parameters of environmental plasticity and stability in the Krasnodar region showed the varieties Selegor with average seed yield by years 4.69 t per ha and Sarmat with yield 4.35 t per ha were the most plastic, adaptive, and genetically adaptable. VN-912, Loris and Elvis were the most stable among all the studied varieties. They possess the better adaptability to deterioration of cultivation conditions. The varieties Olivin, VN-912 and Loris possess high resistance to stress factors.