ANALYSIS OF SIMILARITY BETWEEN GENOTYPES WITH RESPECT TO ECOLOGIC ANDONTOGENIC VARIATION OF A GROWTH TRAIT

A growth trait is considered an indicator of ontogeny in plants with d etermined genotypes (cultivars, Fl hybrids, clones, etc.). A new biome trical-genetic approach is proposed to analyze similarity between geno types; similarity is estimated from shape of reaction of a growth trai t under changing growth conditions in serial competitive field trials. The method is based on regression models that approximate curves of r elative variation of growth of a trait in two genotypes. To estimate s imilarity quantitatively, two parameters are used: smoothness of curve s and their divergence under different conditions of trials (years, re gions, etc.) of two genotypes. This work describes the way to analyze the interrelation between genotypic variation of these paired ontogene tic parameters of similarity and the following parameters: (1) the deg ree of relationship between genotypes and (2) the adequacy of regressi ons on means used to study genotype-environment interaction in ecologi c gradients (from final values of the trait in genotypes).