Specifics of adaptive responses of sunflower hybrids on extreme drought conditions of 2010 in European territory of Russia

An ecological testing of 12 sunflower hybrids was conducted in its main growing areas of European part of Russia in 18 locations in the extremely dry 2010 and in 22 locations in 2011. The average tested yield was from 11 till 40 centners/ha in 2010 and from 16 till 45 centners/ha in 2011. We evaluated the following parameters: an average yield of hybrid i - а ъ a variation coefficient of its yield - CVi, a percentage and an environmental standard deviation - Si, an effect of interaction «genotype-environment» W i (ecovalence), a regression coefficient yields on an environmental index bi, a dispersion of regression residuals S 2di, a similarity (uniformity) degrees of hybrids reactions were evaluated by a coefficient of determination Cd i, a percentage of yields by environmental index, a mathematical expectations of yields of genotype i were calculated by using parameters а and bi within minimum and maximum indexes for its tolerance assessments to stresses and yield potential. As compared with 2011 in dry 2010 S ; and CV ; were higher, but a, W, and S 2d,. were lower. Such decrease of responses specificity of hybrids on a variation of the main stress degree determined high similarity of their reactions, from 90.6 till 98.3%. In more comfortable conditions of 2011 year there were not only increased assessments of the parameter а ъ but also for parameters Wi and S 2di within low Si and CVi. At the same time an increased specificity of hybrids responses was determined by their reactions on qualitatively different stresses linked with higher moisture of the territories. The tested hybrids were classified by a combination of degree of their resistance to stresses of 2010 and 2011 and yield potentials realization in these years. It was determined and explained that a lower equivalence of genotypes assessments by parameters Si and CV b but higher - by parameters Si and bi. It was described a method of assessments corrections Si. It was shown that values S 2^ negatively influence on similarity genotypes reactions degree and values bi - positively.