GENETIC-VARIATION IN DANISH POPULATIONS OF ERYSIPHE-GRAMINIS F.SP. HORDEI - ESTIMATION OF GENE DIVERSITY AND EFFECTIVE POPULATION-SIZE USING RFLP DATA

Genetic variation of the barley powdery mildew fungus (Erysiphe gramin is f.sp. hordei) was estimated in three Danish local populations. Gene tic variation was estimated from the variation amongst clones of Egh, and was therefore an estimate of the maximum genetic variation in the local populations. The average gene diversity, (H) over cap was estima ted as 0.84. The effective population size was estimated as: log(10) ( (N) over cap(e)) = 0.64 - log(10)(mu), or 4.4 x 10(9), assuming a nucl eotide mutation rate (mu) of 10(-9) per base per generation. There was no significant genetic differentiation between locations.