トマト‘ファースト’種子へのイオンビーム照射によって誘発された短節茎突然変異体の生育肥大特性と遺伝様式

Tomato(Lycopersicon esculentum L.) cv. 'First' mutants with short internodes grew vigorously. The number of leaves slightly increased and the shape of the leaves was similar to wild type. In inflorescence morphology, the number of flowers increased and the length of peduncle and pedicel were shorter. In fruit characteristics, weight per fruit, total yield, sugar and acid contents were similar to wild type. But a lot of malformed fruit set was observed in the mutant line, due to the number of locules and short length of the peduncle and pedisel. The segregation ratio of the short internodes character fitted 3:1 of normal:short ,hence it was considered to be contralled by a single pair of recessive genes. Allelism with alresdy known dwart gene was examined by crossing with 'Alisa Craig', which had a symbolized dwart gene, br or bu. Thereby, it was revealed that bu and short internodes gene ware in the same gene locus. This mutant line has no negative effect on plant growth and fruit yield, but was unsuitable for use as fresh fruit by reason of malformed fruits. These results indicated the possibility of breeding of a new cultivar with bu gene derived from 'First'. Since the mutant with short internodes is derived from 'First', which is already a commercial variety with excellent characteristics, raising a new commercial variety with short internodes trait may not take a long time.