摘要
讨论了利用光、温敏核不育两用系的杂交稻育种途径。指出核不育两用系除育性不容易稳定外，其配合力选择受育性选择的制约，造成育种工作的低效率。核不育两用系失去了核质互作型不育系具备的自主防护和被动防护的双重功能。初步应用的低温敏不育系，人工选择和自然选择对温度临界点的压力、方向正好相反，更容易发生混杂退化。核不育两用系繁殖和制种在地域和季节上受到很大限制，而亲本种子却难以控制，可能给杂交稻种子生产带来不良后果。因此，两系法不可能取代三系法而成为杂交稻育种的主要方向。
In order to increase the production of rice, breeders have devoted to the development of two line hybrid rice by using the photo and thermo sensitive genic male sterile(PGMS and TGMS) lines since 1980s. Although some progress has been made, some theoretical and practical problems relating to this breeding system have not yet received sufficient attention. The major problems will include the following: (1)The expression of PGMS and TGMS genes is controlled by the nuclear background and regulated by the environmental conditions at the same time, thus forming a genetic system both of unstable genotypes and phenotypes. For such sterile lines, the efficiency of breeding might be low because selection for sterility must be made prior to selection for combining ability. (2)In most cases, seeding rate of the hybrid progeny of the GMS lines and the restoring lines can hardly reach the acceptable level and it is not easy to select the superior patemal cultivars. (3) The GMS lines do not possess self protection with the sterile cytoplasm and lacks in the function of being protected by means of the maintenance lines as in the CMS lines, and their sterility varies easily with biological mixing. (4) The sterility fertility converting characteristic of the TGMS lines, i.e. the sterility induced by high temperature becomes fertile at low temperature, shows change as the critical temperature from sterility to fertility tends to rise in recent years. Consequently, TGMS lines might not be useful in the production of hybrid rice seed in the near future. (5) Both the seed production of the hybrid rice by using the GMS lines and the reproduction of the GMS lines are greatly limited by regions and seasons, and the scale of seed production is difficult to be controlled. As a result, problems such as low seed qualiy, inreased risks and even failure in seed production will inevitably be encountered. Utilization of the GMS lines in breeding and production of hybrid rice, therefore,would be unsatisfactory in the coming years unless the above problems are solved.
出处
《南京农业大学学报》
CAS
CSCD
北大核心
1996年第4期1-4,共4页
Journal of Nanjing Agricultural University
