Inbreeding depression under intraspecific competition in a highly outcrossing population of Crepis sancta (Asteraceae): evidence for frequency‐dependent variation

摘要: Inbreeding depression is a major selective factor acting to maintain outcrossing in hermaphroditic plants. Recently it has been shown that environmental conditions may greatly affect the levels of inbreeding depression. In this study, the effects of intraspecific competition, from either crossed or inbred progeny, and plant density on the expression of inbreeding depression were estimated for the allogamous colonizing plant Crepis sancta (Asteraceae). The population used in this experiment showed a very high outcrossing rate (t = 0.99). Inbreeding depression was measured for germination, survival to reproduction, number of capitula, and a multiplicative fitness estimate. We found that inbreeding depression on survival, the number of capitula, and total fitness was the greatest when inbred plants compete with outbred plants. The effect of density on inbreeding depression was less evident. The major implication of our …