Restoration of pseudo-self-compatibility (PSC) in derivatives of a high-PSC × no-PSC cross in Nemesia strumosa Benth
SummaryMean PSC increased following each generation of recurrent selection in F1, F2 and F3Nemesia strumosa families derived from a cross of a 100% PSC plant to an unrelated 0% PSC plant. The first 100% PSC individuals occurred in the F4. Populations derived through sib pollination tended to have higher PSC means than lines derived through self pollination. One F3 family showed a three-fold higher PSC level when pollinated in the green-house than when pollinated in the growth chamber, while another F3 family similarly pollinated showed no change in PSC.
The inheritance of pseudo-self compatibility (PSC) in Raphanus sativus L.
SummaryPseudo-self compatibility (PSC) in Raphanus sativus L. is determined by modifying genes that appear to have a threshold effect. Plants that do not possess PSC when used as male or female can produce progeny with increased PSC levels. This suggests that specific combinations and numbers of genes influence PSC. Once high PSC levels are attained, epistatic gene action predominates. Selection of parents for breeding systems using self incompatibility to control fertilization should use progeny testing to determine the best self-incompatible parents.
The genetics of self-incompatibility inLeavenworthia crassa rollins (Cruciferae)
Six plants of a self-incompatible population ofLeavenworthia çrassa were grown from seed collected in nature and cross-pollinated in all combinations. The incompatibility relationships between sibs were determined in eleven of the F1 families. A one-locus sporophytic incompatibility system was established. None of the parents was homozygous at the S locus. At least five, and possibly all six, of the parents did not share an S allele. Only one pair of alleles was shown to have different interactions in the pollen and stigmata. The identity and expression of the S alleles were determined in six families. Eight pairs of alleles were independently expressed in both the pollen grains and the stigmata. Sixteen pairs of alleles showed dominance of one allele over the other in the pollen grains or the stigmata or both.F1 plants of two crosses between different self-incompatible races were self-incompatible. F1 plants of six crosses between self-incompatible and self-compatible races were self-incompatible; in five of the families, the frequency of pseudo-compatibility was higher than in the self-incompatible parent. Self-incompatible hybrids from a cross between a self-incompatible and a self-compatible population provide a method for rapidly determining allelic interactions in plants with a sporophytic incompatibility system.