Genetic analysis of fertility restoration against photoperiod-sensitive cytoplasmic male sterility in Triticum aestivum cv. Norin 61

Triticum aestivum cv. Norin 26 with the Aegilops crassa cytoplasm becomes almost completely male sterile when grown under a long-day condition (15 h of light or longer), but is highly male fertile under a short-day condition (14.5h or less). This type of male sterility is called photoperiod-sensitive cytoplasmic male sterility (PCMS). Genetic analyses were made of the fertility-restoring (Rf) genes effective against PCMS that are present in T. aestivum cv. Norin 61. Conventional and monosomic studies indicated that restoration of fertility is controlled by multiple Rf genes located on at least four chromosomes: 4 A, 1D, 3D and 5D. The genetic mechanism of fertility restoration by the genes of‘Norin 61’differs from the mechanisms reported for‘Chinese Spring’and a‘Norin 26’mutant line.