PHOTOPERIOD-SENSITIVE CYTOPLASMIC MALE-STERILITY INDUCED IN JAPANESE WHEAT CULTIVARS BY TRANSFERRING AEGILOPS CRASSA CYTOPLASM

Triticum aestivum cv, Norin 26 with Aegilops crassa cytoplasm shows photoperiod-sensitive cytoplasmic male sterility (PCMS): The alloplasmic line is almost completely male sterile under long-day conditions (greater than or equal to 15 h light period), but highly male fertile under short-day conditions (less than or equal to 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 B-5 (11 lines) or B-4 (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 lines by transfer of the Ae, crassa cytoplasm, and the latter eight cultivars have demonstrated to carry fertility-restoring (Rf) gene(s) against PCMS, Pedigrees of the Japanese wheat cultivars suggest monophyletic origin of the Rf gene(s).