Application of Esterase and Peroxidase Zymograms to Breeding in Brassica with Reference to Nucleus Substitution

Zymograms of leaf esterases and peroxidases were employed for the use of genetic examination in individual selection to promote nucleus substitution for breeding of new varieties, such as oleracea-cytoplasmic Brassica campestris. In successive strains derived from hybridization of B. oleracea x B. campestris and backcrosses with pollen of ssp. pekinensis, two of the esterases and one of the peroxidases were found to be specific to c genome. The pattern of the enzyme distribution was characterized by these enzymes, and there were two types of the plants in successive backcrossed strains; one had these enzymes specific to c genome, the other had none of them. Frequencies of the plants having the c genome-specific enzymes became lower according to a decrease in the number of chromosomes of c genome, in process of backcrosses with pollen of ssp. pekinensis. From this result, it was estimated that the chromosomes of c genome can be minimized by selecting the plant having none of the enzymes specific to c genome. and this method is useful for breeding of nucleus-substituted strains in Brassica