Mating systems and population structure in two closely related species of the wheat group I. Variation between and within populations

Samples of seven wild populations of the predominantly selfing species Triticam longissimum were compared with samples of five populations of the closely related, but predominantly outcrossing species, T. speltoides. For most of the 36 quantitative characters which were examined, the differences between populations, the total variances of the populations and the mean within-family variances, were greater in the selfer than in the outbreeder. Theoretical models were analysed in an attempt to explain these results, using concepts of classical population genetics.