Genetic control of seed set linked and unlinked to flower heteromorphism in inbred lines of Primula vulgaris Hudson

Analyses of a 12 x 12 diallel cross among inbred lines of Primula vulgaris disclosed considerable genetic variation for seed set, with differences between floral morphs accounting for 37.3% of the total variation. The differences between morphs agree with those reported elsewhere, with intra-thrum crosses being almost sterile, and intra-pin crosses relatively fertile. Inter-morph crosses produced higher seed yield when the thrum morph was used as the maternal parent. Results further showed that significant genetic effects, explaining 25.2% of the total variation, remained when the effects of the heteromorphic incompatibility system had been removed. Analysis revealed that these effects are due mainly to additive genetic differences between the lines and reciprocal general effects. A factorial analysis of the data indicated that differences in seed set capacity occurred only when the lines were evaluated as females. Seed set from within-line and between-line pollinations were highly positively correlated. These results suggest that selection for within-line fertility during inbreeding of parental lines could be an efficient method for improving seed setting in future inbred lines of P. Vulgaris for hybrid seed production.