Kobayashi Asako, Hori Kiyosumi, Yamamoto Toshio, Yano Masahiro
Fukui Agricultural Experiment Station, 52-21 Ryomachi, Fukui, 918-8215, Japan.
National Agriculture and Food Research Organization (NARO), Institute of Crop Science, 2-1-2, Kannondai, Tsukuba, Ibaraki, 305-8518, Japan.
Rice (N Y). 2018 Apr 9;11(1):15. doi: 10.1186/s12284-018-0207-4.
Koshihikari, a Japanese short-grain rice cultivar, was developed in 1956, more than 60 years ago. Despite its age, it has been the most widely grown cultivar in Japan for more than 35 years, making it the most important rice for the Japanese people. In its early days, there was no reason to predict that Koshihikari would become so widely disseminated. However, since the end of the post-World War II food shortage in the 1960s, Japanese preferences changed from high productivity to good eating quality. This triggered wide expansion of Koshihikari cultivation due to the cultivar's excellent taste and texture. With increasing cultivation of Koshihikari in Japan, several good agronomic characteristics beyond its high eating quality became apparent, such as its good adaptation to different environments, tolerance to pre-harvest sprouting, and cold tolerance during the booting stage. These characteristics outweigh drawbacks such as its low blast resistance and low lodging resistance. The popularity of Koshihikari influenced subsequent rice breeding trends at regional agricultural experimental stations, and the characteristics of newly developed rice cultivars in Japan are usually rated relative to Koshihikari, which is used as the benchmark. Koshihikari was the first japonica rice cultivar whose whole genome has been sequenced by means of next-generation sequencing. Furthermore, comparison of the genomes of Koshihikari and Nipponbare has provided detailed insights into the genetic diversity of Japanese rice cultivars relative to that in rice populations elsewhere in the world. Further progress in rice genomics is gradually unlocking the mechanisms that underlie the agronomic characteristics of Koshihikari. To support both research and the development of novel rice cultivars, a series of isogenic and near-isogenic lines in the Koshihikari genetic background have been continuously developed. These new findings and materials will facilitate genomics-assisted rice breeding, eventually leading to superior cultivars.
越光，一种日本短粒水稻品种，于60多年前的1956年培育而成。尽管年代久远，但它在35年多的时间里一直是日本种植最广泛的品种，成为日本人最重要的大米。在其早期，没有理由预测越光会如此广泛地传播。然而，自20世纪60年代二战后粮食短缺结束以来，日本人的偏好从高产量转向了良好的食用品质。由于该品种出色的口感和质地，这引发了越光种植的广泛扩张。随着越光在日本种植面积的增加，除了其高食用品质外，它还展现出了一些良好的农艺特性，比如对不同环境的良好适应性、对穗发芽的耐受性以及孕穗期的耐寒性。这些特性超过了其诸如抗稻瘟病能力低和抗倒伏能力低等缺点。越光的受欢迎程度影响了地区农业试验站随后的水稻育种趋势，日本新培育的水稻品种的特性通常相对于作为基准的越光进行评级。越光是第一个通过下一代测序完成全基因组测序的粳稻品种。此外，越光和日本晴基因组的比较为了解日本水稻品种相对于世界其他地方水稻群体的遗传多样性提供了详细的见解。水稻基因组学的进一步进展正在逐步揭示越光农艺特性背后的机制。为了支持水稻研究和新品种的开发，一系列以越光为遗传背景的同基因系和近等基因系不断被培育出来。这些新发现和材料将促进基因组学辅助的水稻育种，最终培育出更优良的品种。
