Development of the Functional Male Sterile Line of Eggplant Utilizing the Cytoplasm of Solanum kurzii by Way of the Amphidiploid

To develop a male sterile eggplant (Solanum melongena L.), cytoplasm substitution lines of eggplant were produced by continuous backcrossing between S. kurzii Brace ＆ Prain and eggplant using S. kurzii as cytoplasm donor and eggplant as nucleus one by way of the amphidiploid. Analyses of chloroplast DNA and mitochondrial DNA confirmed that all the backcross progenies (the BC1, BC2, BC3, BC4, and BC5) had the cytoplasm from S. kurzii. Anthers in all the backcross progenies were indehiscent type (i.e., pollen non-release type) without segregation. The pollen germination ability of the BC3, BC4 and BC5 plants were about less than 4％. The number of seeds per fruit increased dramatically in the BC4 plants and the average numbers of the BC4 and BC5 plants were about 230 and 360, respectively. The functional male sterility of the anther indehiscent type was shown to be attributed due to incompatibility between the cytoplasm of S. kurzii and nuclear genes of S. melongena. The present CMS plants is promising compared to the one that was backcrossed without going through the amphidiploid, because the CMS is fixed early and the pollen germination ability is extremely low.