Abstract
‘Taibyo VF’, a Japanese rootstock cultivar, is a Solanum grandifolium × S. melongena hybrid that has difficulty setting seed, but F1 plants of ‘Taibyo VF’ × ‘LS1934’ (S. melongena) produce some seeds. F2 plants were segregated into male-sterile and fertile plants. All plants in the backcross of sterile progeny with S. melongena were sterile, indicating cytoplasmic male sterility (CMS) caused by the S. grandifolium cytoplasm. This CMS is stable under a range of environmental conditions. In contrast, fertile progeny appear to possess a fertility restoration nuclear gene. We studied the inheritance of this gene. F1, F2, and backcross generations from crosses between male-sterile ‘CMS-1’ and fertile ‘FR-1-1’ were obtained. ‘CMS-1’ is the F1 of male-sterile ‘ER98B-10-2-3-1’ × ‘AE-P08’ (S. melongena). ‘ER98B-10-2-3-1’ is the F5 and ‘FR-1-1’ is the F7 of ‘Taibyo VF’ × ‘LS1934’. All ‘CMS-1’ plants were male-sterile; the fertile to male-sterile segregation ratios were 3 : 1 in ‘FR-1-1’, 1 : 1 in F1 and 3 : 1 in F2 of ‘CMS-1’ × ‘FR-1-1’, and 1 : 1 in ‘CMS-1’//‘CMS-1’/‘FR-1-1’. Segregation ratios suggested that fertility restoration is controlled by a single dominant gene (Rf) carried heterozygously in ‘FR-1-1’. Restorer lines that carry nuclear Rf homozygously in the cytoplasm of S. melongena have been developed.
