Background

In temperate rice cultivation regions, japonica rice cultivars are grown preferentially because consumers deem them to have good eating quality, whereas indica rice cultivars have high grain yields and strong heat tolerance but are considered to have poor eating quality. To mitigate the effects of global warming on rice production, it is important to develop novel rice cultivars with both desirable eating quality and resilience to high temperatures. Eating quality and agronomic traits were evaluated in a reciprocal set of chromosome segment substitution lines derived from crosses between a japonica rice cultivar ‘Koshihikari’ and an indica rice cultivar ‘Takanari’.

Results

We detected 112 QTLs for amylose and protein contents, whiteness, stickiness, hardness and eating quality of cooked rice grains. Almost of ‘Koshihikari’ chromosome segments consistently improved eating quality. Among detected QTLs, six QTLs on chromosomes 1–5 and 11 were detected that increased whiteness and stickiness of cooked grains or decreased their hardness for 3 years. The QTLs on chromosomes 2–4 were not associated with differences in amylose or protein contents. QTLs on chromosomes 1–5 did not coincide with QTLs for agronomic traits such as heading date, culm length, panicle length, spikelet fertility and grain yield. Genetic effects of the detected QTLs were confirmed in substitution lines carrying chromosome segments from five other indica cultivars in the ‘Koshihikari’ genetic background.

Conclusion

The detected QTLs were associated with differences in eating quality between indica and japonica rice cultivars. These QTLs appear to be widely distributed among indica cultivars and to be novel genetic factors for eating quality traits because their chromosome regions differed from those of the GBSSI (Wx) and SSIIa (Alk) genes. The detected QTLs would be very useful for improvement of eating quality of indica rice cultivars in breeding programs.

中文翻译：

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j稻和粳稻品种除Wx和Alk基因外，其他饮食和烹饪质量差异的基因组区域

背景

在温带水稻种植区，粳水稻品种优先发展，因为消费者认为他们有良好的饮食质量，而籼水稻品种具有较高的籽粒产量和较强的耐热性，但都被认为具有食用品质较差。为了减轻全球变暖对水稻生产的影响，重要的是开发兼具理想的食用品质和高温耐受性的新型水稻品种。食用品质和农艺性状在倒数组从杂交之间的染色体片段置换系进行了评价粳稻水稻品种“越光”和籼稻品种“Takanari”。

结果

我们检测了112个QTL，包括米饭中直链淀粉和蛋白质含量，白度，粘性，硬度和食用质量。几乎所有的“越光”染色体片段都能持续改善饮食质量。在检测到的QTL中，检测到1–5和11号染色体上的6个QTL，它们使煮熟的谷物的白度和粘性增加，或降低了3年的硬度。2-4号染色体上的QTL与直链淀粉或蛋白质含量的差异无关。1-5号染色体上的QTL与农艺性状（例如抽穗期，茎长，穗长，小穗育性和谷物产量）的QTL不一致。所检测到的QTL的遗传效应在从其他五个携带染色体片段置换系被证实籼稻在“越光”遗传背景的品种。

结论

所检测到的QTL用饮食之间质量差异有关籼稻和粳稻水稻品种。这些QTL似乎中广泛分发籼稻品种和是新颖的遗传因素食用品质性状，因为它们的染色体区域不同于的不同GBSSI（蜡质）和的SSIIa（ALK）基因。检测到的QTL将是改善饮食质量非常有用籼稻育种程序水稻品种。