水稻籽粒大小相关性状QTL定位

Mapping of QTLs Controlling Rice Grain Size

【目的】水稻籽粒大小是影响产量和品质的数量性状,籽粒大小相关QTLs的定位是进一步克隆、功能研究以及分子育种的基础。【方法】用1个大粒水稻ZD05321和斯里兰卡的极小粒Suwandel为亲本,创建了1个246个单株的F2群体,用48个SSR标记对控制粒长、粒宽、千粒重和长宽比进行QTLs定位分析。【结果】F2群体粒长、粒宽、千粒重等性状呈现连续分布的数量性状遗传特点,多数植株的表型偏向大粒亲本。粒长、粒宽与千粒重都存在极显著的正相关;随着粒重的增加,粒长对粒重的作用逐渐变小。在第1、4、6、7、8和9号染色体上,共检测到15个与籽粒大小相关的QTL,单个性状QTL为3~5个,可分别解释1.02%~16.52%的相应性状变异。在第9染色体上检测到同时控制粒长、粒宽、千粒重和长宽比等4个性状的4个QTL,它们位于该染色体的RM3609~RM7586和RM6543~RM566区段上。【结论】大粒亲本ZD05321中可能存在控制籽粒大小的效应值较大的QTLs,第9染色体上存在同时控制多个粒形性状区域,为下一步精细定位这些新的粒形相关QTL奠定了基础。

[Purpose] Grain size controlled by QTLs dispersed in rice genome is a quantitative trait that influence both the quality and yield of rice,and locating those QTLs is the first steps for further research,such as QTL clone and function analysis. [Method]A lager grain size rice variety,ZD05321 was crossed with a very small grain size variety Suwandel to produce a F_2 population containing 246 lines. And the QTLs involving 4 grain size related traits,including grain length（ GL）,grain width（ GW）,thousand grain weight（ TGW） and length-width ratio（ L/W） were mapped with 48 SSR molecular markers in this F_2 population. [Results]Genetic analysis showed that the GL,GW and TGW in the F_2 population present continuous distribution as the typical quantitative traits. The phenotype ofmost plants in the F_2 population is in favor of the lager grain size rice variety,ZD05321. There is an extremely remarkable positive correlation among GL,GW and TGW. And with the increase of grain weight,the grain length makes less contribution to grain weight. A total of 15 QTLs relevant to grain size were detected,in the 1 st,4 th,6 th,7 th,8 th and 9 th chromosomes in the rice,the number of QTLs detected for each trait are 3 to 5,and with the contribution of 1. 02% to 16. 52% to the corresponding characters. There are 4 QTLs relevant to grain length,grain width,thousand grain weight and length-width ratio were detected on the 9 th chromosome,and these QTLs are located in the segment of RM3609-RM7586 and RM6543-RM566. [Conclusion]There may exist major QTLs which control the grain size within the larger grain size variety ZD05321. A chromosome region which control several grain size traits was discovered in the 9 th chromosome,and this is the basis for fine mapping the related QTLs in this region in the future study.