THE GENETIC-CONTROL OF 7 ISOZYMIC LOCI IN VICIA-FABA L IDENTIFICATIONOF LINES AND ESTIMATES OF OUTCROSSING RATES BETWEEN PLANTS POLLINATEDBY BUMBLE BEES

A simplified and non-destructive method using starch gel electrophores is has been developed on seeds to identify inbred lines of Vicia faba and assess outcrossing rates and gene dispersal in pollination experim ents. Six enzyme systems (Alcohol dehydrogenase, Aspartate aminotransf erase, Glucose-6-phosphate isomerase, Isocitrate dehydrogenase, Phosph ogluconate dehydrogenase and Shikimate dehydrogenase) were analysed fr om parental lines, crosses performed between lines bearing dissimilar isozyme patterns in pollination cages with Bombus and F2 progenies obt ained from manual selfing of F1 hybrids. The allozymes at each of the seven studied loci segregated in the expected Mendelian fashion and be haved in a co-dominant manner except for the Adh-2 locus where the onl y variant was a null allele. No evidence of genetic linkage was observ ed between at least 13 of the 15 pairs of the studied loci. Percentage of cross fertilisation by Bombus between seven pairs of inbred lines ranged between 1.7% and 28.3%. Pollen transfer between a donor line an d a recipient line by two species of Bombus did not lead to difference s in outcrossing rates (both about 8%). The new PGD marker with two lo ci at three alleles each is particularly discriminating and valuable i n pollination studies and breeding of V. faba.