Inbreeding depression and outcrossing rate in the endangered autotetraploid plant Aster kantoensis (Asteraceae)

Inbreeding depression in a population of an endangered autotetraploid plant , Aster kantoensis (Asteraceae), was estimated over a 2 year period. The fi rst-year survival rate of the outcrossed progeny was significantly higher t han that of the self ed progeny. After 2 years the number of flowers per re productive individual was also greater in the outcrossed progeny, and the c omposite Value of inbreeding depression was 0.790. The multilocus estimate of outcrossing rate in the population is 0.883 +/- 0.064. The high value of inbreeding depression is consistent with the predominant outcrossing of th e population.