ALLOZYME DIVERSITY IN LEAVENWORTHIA POPULATIONS WITH DIFFERENT INBREEDING LEVELS

Levels of allozyme diversity were studied in five species of the annua l plant genus Leavenworthia. The breeding systems of the populations w ere also characterized in terms of measures of autogamous seed-set and self-fertility. The populations that appeared more inbreeding by thes e criteria also tended to have lower within-population gene diversity (H-s) values, but there was nevertheless considerable allozyme variabi lity in two of the four sets of inbred populations studied. Comparing the outcrosser L. stylosa and the related inbreeders L. uniflora and L . torulosa the reduction in diversity associated with inbreeding was v ery high, as no variants were seen within populations of the inbreeder s. In L. crassa and L. alabamica, the reduction was lower, but correct ing for the fact that this comparison is over less extreme selfing rat e differences, it is estimated that the difference between extreme inb reeding and outcrossing populations of L. crassa considerably exceeds twofold. These results are compared with published studies within clos ely related taxa with different inbreeding levels. The effect of inbre eding on allozyme diversity is consistently larger thats has been esti mated from comparisons of unrelated species.