Relationship between genetic distance based on isoenzyme and heterosis in tobacco (Nicotiana tabacum L.)

Nine kinds of isoenzyme were analyzed by the techniques of polyacruylamide gel electrophoresis (PAGE) among parents in tobaco. Most bands were constant for all varieties, but 17 bands showed intervarietal polymorphism. The parents were clustered into 3 groups by genetic distance based on 17 polymorphic bands, most of cultivars within same group were from same area. There was no correlation between isozyme genetic distance and yield heterosis, but most of crosses with higher heterosis were these hybrids that their parents were from different groups. The result suggested that it might be better to select cultivars from different groups as crossing parents in heteroisis breeding.