Toyama Prefectural Agricultural, Forestry & Fisheries Research Center , 1124-1 Yoshioka, Toyama, Toyama 939-8153 , Japan.
Breed Sci. 2014 Dec;64(4):273-81. doi: 10.1270/jsbbs.64.273. Epub 2014 Dec 1.
The appearance of brown rice grown under high temperature conditions is an important characteristic for improvement in Japanese rice breeding programs. We performed a QTL analysis of the appearance quality of brown rice using chromosome segment substitution lines of the indica cultivar 'Habataki' in the 'Koshihikari' genetic background. A line carrying a 'Habataki' segment on chromosome 7 showed a high percentage of perfect grains produced under high temperature conditions during the ripening period. To verify the role of this segment, and to narrow down the region containing the useful allele, substitution mapping was performed using multiple paired lines. As a result, the chromosomal location of a gene that we named Appearance quality of brown rice 1 (Apq1) was delimited to a 48-kb region. In addition, we developed an Apq1-near isogenic line (NIL) to evaluate the effect of Apq1 on various agronomic traits. Under high temperature conditions during the ripening period, the Apq1-NIL produced significantly higher percentages of perfect grains than 'Koshihikari'. Other agronomic traits, including yield and palatability, were similar between the Apq1-NIL and 'Koshihikari'. Therefore, the 'Habataki' allele of Apq1 will be useful in breeding programs aimed at improving the quality of grains ripened under high temperature conditions.
高温条件下糙米的外观是日本水稻育种计划改良的一个重要特征。我们利用籼稻品种 'Habataki'在 'Koshihikari'遗传背景下的染色体片段代换系，对糙米外观品质进行了 QTL 分析。在成熟期高温条件下，携带 7 号染色体 'Habataki'片段的系表现出较高比例的完美粒。为了验证该片段的作用，并缩小含有有用等位基因的区域，我们使用多个配对系进行了代换作图。结果，将我们命名为糙米外观品质 1（Apq1）的基因的染色体位置限定在 48kb 区域内。此外，我们开发了一个 Apq1 近等基因系（NIL），以评估 Apq1 对各种农艺性状的影响。在成熟期高温条件下，Apq1-NIL 产生的完美粒比例明显高于 'Koshihikari'。其他农艺性状，包括产量和口感，在 Apq1-NIL 和 'Koshihikari'之间相似。因此，Apq1 的 'Habataki'等位基因将有助于在高温条件下改良成熟粒品质的育种计划。
