光敏核不育水稻在籼粳亚种间杂种优势利用问题的探讨

Some Problems in Using Photoperiod-Sensitive Genie Male Sterile Rice for Indica-Japonica Heterosis

光敏核不育水稻(PGMSR)在南京(32°03′N)自然温光条件下从不育到可育的转换期因材料不同而异,粳型早于籼型。中粳型和早、中籼型PGMSR的不育期长,但多数材料的不育性易受温度影响;晚粳型和晚籼型PGMSR的不育期短,未能观察到温度对不育性的影响。早籼型PGMSR与粳型广亲和系配组,虽有一定优势,但生育期明显推迟;用中籼型PGMSR与粳型广亲和系配组,较易找到熟期适宜、产量优势较强的组合。

The exploitation of photoperiod-sensitive genie male sterile rice (PGMSR) offers the possibility of transition from the three-line method to the two-line method for the use of heterosis in rice. A joint breeding program to develop the two-line method based on the utilization of PGMSR has been initiated in China. In 1987-1989, several problems of PGMSR such as fertility expression, stability of sterility, performance of F_1 hybrids, etc. were probed into, and some results different from those in earlier reports were obtained.1. The date of fertility change from sterile to fertile of PGMSR under the natural conditions in Nanjing (32?03' N) was different with the genotypes. The date for the japonica type (mostly Augest 30桽eptember 6) was earlier than that of the indica type (September 6?0) (Tabe 1). The indica type with early and medium maturity and the japonica type with medium maturity had long sterile periods, but their sterility was easily affected by temperature (Fig. 1). The indica and japonica s with late maturity had' short sterile periods and the temperature effect on sterility was not observed.2. To produce inter-subspecies hybrids by using the indica type PGMSR was not as easy as considered earlier. It would be difficult to use late maturing indica type PGMSR because of its short sterile period. The hybrids between the early maturing indica type PGMSR and the japonica type wide compatibility line (WCL) showed some heterosis in numbers of panicles and spikelets compared with the indica rice hybrid Shan-you 63, but has too long growth duration. It is possible to produce hybrids with a suitable mature period and strong heterosis in grain yield by crossing between the intermediate maturing indica type PGMSR and the japonica type WCL (Table 2, 3), but the unstable sterility would be the main barrier.