Background

Grain chalkiness is one of important factors affected rice grain quality. It is known that chalkiness is affected by the high temperature during the seed filling period. Although a larger of QTLs for chalkiness were reported across all 12 chromosomes, only a few of the QTLs were fine mapped or cloned up to now. Here, we fine map two QTLs for chalkiness in two single-segment substitution lines (SSSLs), 11–09 with substitution segment from O. sativa and HP67–11 with substitution segment from O. glaberrima.

Results

The grain chalkiness of SSSLs 11–09 and HP67–11 was significantly lower than that in the recipient Huajingxian 74 (HJX74) in consecutive 8 cropping seasons. The regression correlation analysis showed that percentage of chalky grain (PCG) and percentage of chalky area (PCA) were significantly and positively correlated with percentage of grain chalkiness (PGC). Two QTLs for grain chalkiness were located on two chromosomes by substitution mapping. qPGC9 was mapped on chromosome 9 with an estimated interval of 345.6 kb. qPGC11 was located on chromosome 11 and delimited to a 432.1 kb interval in the O. sativa genome and a 332.9 kb interval in the O. glaberrima genome. qPGC11 is a QTL for grain chalkiness from O. glaberrima and was mapped in a new region of chromosome 11. The effect of two QTLs was incomplete dominance. The additive effects of two QTLs on chalkiness in second cropping season (SCS) were significantly greater than that in first cropping season (FCS).

Conclusions

qPGC11 is a new QTL for grain chalkiness. The two QTLs were fine mapped. The donor alleles of qPGC9 and qPGC11 were sensitive to the high temperature of FCS.

中文翻译：

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水稻中两个对高温敏感的垩白度QTL的精细定位

背景

谷物白垩度是影响稻米品质的重要因素之一。众所周知，垩白度受种子灌装期的高温影响。尽管在所有12条染色体上都报告了较大的白垩化QTL，但到目前为止，只有少数QTL进行了精细定位或克隆。在这里，我们在两个单段替换系（SSSL）中精细绘制了两个QTL的垩白度，其中O- sativa的替换片段为11-09，而O. glaberrima的替换片段为HP67-11 。

结果

在连续8个种植季节中，SSSLs 11–09和HP67–11的谷粒垩白度显着低于受精华粳74（HJX74）。回归相关分析表明，垩白粒率（PCG）和垩白面积率（PCA）与谷粒垩白率（PGC）显着正相关。通过取代作图将两个用于谷物垩白度的QTL定位在两个染色体上。将qPGC9定位在9号染色体上，估计间隔为345.6 kb。qPGC11位于11号染色体上，在O. sativa基因组中的间隔为432.1 kb，在O. glaberrima基因组中的间隔为332.9 kb 。qPGC11是来自谷物的白垩度的QTLO. glaberrima，被定位在11号染色体的新区域。两个QTL的影响是不完全的优势。在第二个种植季节（SCS），两个QTL对白垩度的累加效果显着大于第一个种植季节（FCS）。

结论

qPGC11是一种用于谷物白垩度的新QTL。两个QTL进行了精细映射。qPGC9和qPGC11的供体等位基因对FCS的高温敏感。