GENETIC-ANALYSIS ON THE FERTILITY RESTORATION BY TRITICUM-AESTIVUM CVCHINESE SPRING AGAINST PHOTOPERIOD-SENSITIVE CYTOPLASMIC MALE-STERILITY

Triticum aestivum cv. Norin 26 with Aegilops crassa cytoplasm shows ph otoperiod-sensitive cytoplasmic male sterility (PCMS). This alloplasmi c line is almost completely male sterile under a long-day condition (g reater-than-or-equal-to 15 h light period), but highly male fertile un der a short-day condition (less-than-or-equal-to 14.5 h light period). The alloplasmic line of T. aestivum cv. Chinese Spring with the same cytoplasm does not express PCMS. Conventional and telosomic analyses r evealed that the fertility restoration manifested by Chinese Spring is controlled mainly by a single dominant gene (designated Rfd1) located on the long arm of chromosome 7B, and that a large number of modifier s are involved in modifying the level of fertility restoration. The fu nction of the Rfd1 gene is expressed sporophytically. A slight certati on was observed between the two types of pollen grains, one carrying a nd the other not carrying this gene, under the presence of Ae. crassa cytoplasm.