GENETIC DIVERSITY OF FRENCH COMMON WHEAT GERMPLASM BASED ON GLIADIN ALLELES

Analysis of gliadin electrophoretic (APAGE) patterns made it possible to identify 79 alleles at six Gli-1 and Gli-2 loci (from 9 to 18 per l ocus) and 173 gliadin genotypes in the 187 French common wheat cultiva rs considered. Six new alleles were registered in the catalogue of gli adin alleles. The genetic diversity of French common wheats was found to be high (H = 0.714) and had not changed much during the last 25-50 years. Analysis of genetic distances showed some gradual changes in Fr ench wheat germplasm over the course of time. Genetic distances betwee n French and several European wheat germplasm were analysed; genotypes of European wheats were found to relate very distantly to Canadian ge notypes. The considerable differentiation of wheat genotypes from diff erent countries and cereal companies might be caused by breeders' pers onal preferences and by hidden natural selection specific to each loca l environment. In French cultivars, genetic variation in earliness, an d in the North/South habit of the cultivars studied, correlated signif icantly with allelic variation at Gli-B1, Gli-A2 and Gli-D2 for earlin ess, and at Gli-D2 for the North/South habit. Early and late cultivars are grown mainly in Southern and Northern France, respectively (r(2) = 0.30). Cultivars having either the 1B/1R translocation or allele Gli -D2g are, on average, later and more resistant to cold; they hence are grown in the North of France. Alternatively, cultivars with the allel e Gli-D2m are earlier and cold-sensitive, and are grown in the South o f France.