Some features of determination of a genetic purity of sunflower lines and hybrids by a method of isozyme analysis

The main task of sunflower hybrid seed growing is maintenance on a high level of genetic purity of sunflower hybrids and inbreds. The method of analysis of isozyme spectra is effective for control of the genetic purity of seed lots. At the laboratory of immunity and molecular marking of VNIIMK the genetic purity of inbreds from the multiplication plots and F1 hybrids from the hybridization plots have been analyzing by this method for a long time. The purpose of this work is a characteristic of peculiarities appearing at analyzing of the genetic purity of sunflower lines and hybrids. Sunflower seeds of self-pollinated parental lines and F1 hybrids NIIMK breeding were used as material for research. For description of seed lots there was used a method of analysis of electrophoretic spectra of five isozyme systems. Genetic purity of simple hybrids can be estimated on all analyzed isozyme loci but a level of hybridization is determined only by loci being in heterozygous state. If one of the parental form of three-way hybrids is in heterozygous state due to any isozyme loci then in F1 this trait specifies segregation on analyzing type and the genetic purity of a hybrid is determined only by those loci which are in homo- or heterozygous state. This leads to decreasing of a quantity of analyzed marker systems and to lowering of accuracy of estimation of the seed lots genetic purity. There can be in-line variability of traits at breeding lines which are not used for selection. And this can cause underestimation of indicators of typicality at using the method of isozymes for analysis. At formation of plots for growing of breeders seeds of lines of commercial hybrids it is recommended to analyze isozymes with a purpose to discard progenies heterogenic even though on one system.