Abstract
Triticum aestivum cv. Norin 26 with Aegilops crassa cytoplasm shows photoperiodsensitive cytoplasmic male sterility (PCMS): The alloplasmic line is almost completely male sterile under longday conditions (≥l5 h light period), but highly male fertile under shortday conditions (≤14.5 h). To examine the effects of the Ae. crassa cytoplasm on other wheat cultivars, this cytoplasm was introduced into 17 Japanese wheat cultivars by repeated backcrosses. Among their alloplasmic lines which reached B5 (11 lines) or B4 (six lines) generation, those of nine cultivars showed PCMS caused by the Ae. crassa cytoplasm, while those of other eight cultivars did not. Thus, the former nine cultivars are converted to the PCMS Iines by transfer of the Ae. crassa cytoplasm, and the latter eight cultivars have demonstrated to carry fertilityrestoring (Rf) gene(s) against PCMS. Pedigrees of the Japanese wheat cultivars suggest monophyletic origin of the Rf gene(s).
