GYNODIOECY AND MITOCHONDRIAL-DNA POLYMORPHISM IN NATURAL-POPULATIONS OF BETA-VULGARIS SP MARITIMA

Gynodioecious populations of Beta vulgaris ssp maritima were found all along the French coasts; 42% of the populations were gynodioecious. Locally, there were large sex-ratio differences between populations, ranging from 0 to 76% of females. This large variation was even found between populations less than 1 km apart. Molecular analysis of mitochondrial polymorphism revealed a high variability; 11 different mitochondrial types were found. The Nvulg type, which is the most frequent type among the maintainers of male sterility used in sugar beet breeding programs, was also the most frequent type in natural populations. Conversely, the characteristic pattern of the Owen CMS (cytoplasmic male sterility), ie the Svulg type, was not found. The mitochondrial variability detected within the populations was large; there were 2.10 different mitotypes on average among the 5 individuals sampled per population. There was a highly significant overall difference in mitotype frequencies between populations (Fst = 0.466; P < 0.001), distributed both between (Fst = 0.138; P < 0.001) and within regions (Fst = 0.381; P < 0.001). Female plants were found with almost all of the different mitotypes. Nevertheless, 2 groups of mitotypes were clearly distinguished: the mitotypes Nvulg, A and B were rarely associated with the female phenotype, whereas female plants were often found among the plants having the mitotypes E and G.