Genetic variation of the self-incompatibility alleles (s-alleles) in the cultivated radish (Raphanus sativus L.) by the PCR-RFLP method

Radish exhibits sporophytic self-incompatibility with multiple S-alleles located at a single locus. Most radish cultivars are becoming F-1 hybrids and the hybrid seeds are produced using self-incompatibility. Thus, it is very significant that the S-genotypes of the plants can be identified before flowering using the PCR RFLP method. We aimed to identify the S-allele genetic variations of the cultivated radish and distinguish usable S-alleles for Fl seed production. We investigated 71 inbred lines, which are homozygous at the S-locus and used as parents of commercial F-1 hybrids, and 219 lines belonging to 23 local varietal groups; 18 Japanese varietal groups and 5 non-Japanese varietal groups (from Europe. Korea, Nepal, North China and South China). Thirty seven S-alleles, designated as S-20T to S-237. were identified. Twenty-nine of the thirty-seven S-alleles could be amplified by the PCR and identified by MspI-digestion. No PCR products were found in the other S-alleles. We will discuss the diversification of the S-alleles in the radish.