Self-incompatibility is codominant in intraspecific hybrids of self-compatible and self-incompatible Lycopersicon peruvianum and L. hirsutum based on protein and DNA marker analysis

Abstract

Self-compatibility was investigated separately in two species of tomato, Lycopersicon peruvianum and L. hirsutum. The codominant expression of self-compatibility (SC)/self incompatibility (SI) was established using intraspecific hybrids of SC and SI hybrids. In SC L. peruvianum, a major stylar protein of approximately 29 kDa cosegregates with self-compatibility in the progeny of SC/SI hybrids. The SC/SI hybrids are self-fertile, but only partially so, since the SI allele present in the hybrids is capable of eliminating certain genotypes in the resultant progeny. In L. hirsutum, the majority of hybrids between one accession of SI L. hirsutum f. hirsutum and one of SC L. hirsutum f. glabratum are self-fertile. Analysis of the progeny revealed that the SC and SI alleles are codominant in this species as well. A protein product for the SC allele is not obvious in style extracts of L. hirsutum f. glabratum. Segregating progeny from SC/SI hybrids of L. hirsutum were used to map the S locus against five RFLP markers on chromosome 1, and estimated map distances are given. In addition, evidence is presented that indicates that one of the DNA markers, CD15, is duplicated in L. hirsutum f. glabratum, and the duplication is not linked to the S locus.