Stacking S5-n and f5-n to overcome sterility in indica-japonica hybrid rice
Stacking S5-n and f5-n to overcome sterility in indica-japonica hybrid rice
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堆叠S5-n和f5-n克服籼粳杂交稻不育性
DOI：
10.1007/s00122-015-2648-0
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发表时间：
2016-03-01
影响因子：
5.4
通讯作者：
Mou, Tongmin
中科院分区：
文献类型：
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作者：
Mi, Jiaming;Li, Guangwei;Mou, Tongmin
关键信息 S5-n和f5-n的金字塔累积提高了籼粳杂交种的结实率，为水稻育种中利用亚种间杂种优势提供了有效途径。籼粳杂交稻育种是提高水稻产量的一个有吸引力的途径。然而，杂种不育是利用亚种间杂种优势的主要障碍。广泛亲和性等位基因可以打破籼稻和粳稻亚种之间的育性障碍，有可能克服亚种间杂种不育。在这里，我们通过引入两个广亲和性等位基因 S5-n 和 f5-n，分别调节胚囊和花粉育性，提高了优良籼稻恢复系 9311 与广谱粳稻品种的相容性。通过整合回交育种，获得了两个携带S5-n或f5-n的近等基因系和一个携带S5-n加f5-n的金字塔系，轮回亲本基因组恢复率分别为99.95%、99.49%和99.44%。当与典型的籼稻测试者杂交时，这三个品系显示出正常的生育力。当与五个典型的粳稻品种进行测试杂交时，这些品系可以显着提高相容性并保持恒定的农艺性能。渗入的S5-n可显着提高籼粳杂交种胚囊育性14.7-32.9%。此外，由于存在 f5-n 片段，S5-n 会将小穗育性从 9.5% 提高到 21.8%。基因渗入的f5-n片段极大地改善了籼粳杂交种的花药开裂、胚囊和花粉育性，从而使小穗育性从20.4%提高到30.9%。此外，金字塔系显示小穗育性增加了 33.6-46.7%，表明 S5-n 和 f5-n 片段在亚种间杂种结实率提高中的累积效应。我们的研究结果为利用籼粳亚种之间的杂种优势提供了有效的方法，这对水稻育种具有深远的意义。
Key message Pyramiding of S5-n and f5-n cumulatively improved seed-setting rate of indica-japonica hybrids, which provided an effective approach for utilization of inter-subspecific heterosis in rice breeding.Breeding for indica-japonica hybrid rice is an attractive approach to increase rice yield. However, hybrid sterility is a major obstacle in utilization of inter-subspecific heterosis. Wide-compatibility alleles can break the fertility barrier between indica and japonica subspecies, which have the potential to overcome inter-subspecific hybrid sterility. Here, we improved the compatibility of an elite indica restorer line 9311 to a broad spectrum of japonica varieties, by introducing two wide-compatibility alleles, S5-n and f5-n, regulating embryo-sac and pollen fertility, respectively. Through integrated backcross breeding, two near isogenic lines harboring either S5-n or f5-n and a pyramiding line carrying S5-n plus f5-n were obtained, with the recurrent parent genome recovery of 99.95, 99.49, and 99.44 %, respectively. The three lines showed normal fertility when crossed to typical indica testers. When testcrossed to five typical japonica varieties, these lines allowed significant increase of compatibility with constant agronomic performance. The introgressed S5-n could significantly improve 14.7-32.9 % embryo-sac fertility in indica-japonica hybrids. In addition, with the presence of f5-n fragment, S5-n would increase the spikelet fertility from 9.5 to 21.8 %. The introgressed f5-n fragment greatly improved anther dehiscence, embryo-sac and pollen fertility in indica-japonica hybrids, thus leading to improvement of spikelet fertility from 20.4 to 30.9 %. Moreover, the pyramiding line showed 33.6-46.7 % increase of spikelet fertility, suggesting cumulative effect of S5-n and f5-n fragment in seed-set improvement of inter-subspecific hybrids. Our results provided an effective approach for exploiting heterosis between indica and japonica subspecies, which had a profound implication in rice breeding.