Abstract:

Since the discovery of the mutant (Nongken 58S) in Nongken 58 (Oryza sativa ssp. japonica) field by SHI Ming-Song in Hubei Province in 1973, many P(T)GMS (photoperiod (thermo)-sensitive genic male sterile) lines derived from Nongken 58S have been developed. Nongken 58S is PGMS (photoperiod-sensitive genic male sterile) rice which fertilize in short day-length and low temperature condition and sterilize in long day-length and high temperature condition. Genetic studies have shown that PGMS gene of Nongken 58S is governed by one or two recessive genes. Allelism of sterile genes of Nongken 58S and its derivative lines was founded that sterile gene of Nongken 58S is allelic to that of P(T)GMS line derived from Nongken 58S, but not allelic to non-Nongken 58S derivative P(T)GMS lines. go543S is low temperature induced recessive genic male sterile rice which fertilize in high temperature condition and sterilize in low temperature condition. In order to study the interaction of those recessive sterile genes whose effects of photoperiod and temperature on the fertility are reverse, 7 hybrids between go543S and Nongken 58S and its derivatives 7001S, Pei’ai 64S, Changxuan 3S and 8 backcrosses were made. Hybrids F₁ was sterile during whole growth season under natural condition（2004，Changsha, Hunan, China; Table 1）, which indicated that sterile genes of go543S was phenotypically allelic to gene of P(T)GMS lines derived from Nongken 58S. However the hybrids F₁ did not fertilized in high temperature condition as go543S did, and did not fertilized in low temperature and short day-length condition either as Nongken 58S and its’ derivatives. It is evident that the genes of P(T)GMS rice are epistasis to the genes of go543S under high temperature with long day-length, while under low temperature with short day-length the genes of go543S are epistasis to the genes of P(T)GMS rice. Similar results were obtained from greenhouse treatment under long day-length and high temperature condition and short day-length and low temperature condition (Table 2). Frequency distribution of fertile segregation in the backcross of the hybrids of go543S and P(T)GMS rice was founded that the backcrosses with female parent go543S were recorded half low temperature induced recessive genic male sterile plants whose fertility was similar to that of go543S (Fig.1, Fig.2), while those with male parents were recorded half P(T)GMS plants which were fertile under low temperature with short day-length, indicating goodness-of- fit to Medelian ratio for recessive sterile genes.

Key words: Rice (Oryza sativa L.), Low temperature induced genic male sterile, Photoperiod-(thermo) sensitive genic male sterile (PGMS), Fertility