Asian cultivated rice (Oryza sativa L.) is divided into two subspecies, indica (O. sativa L. subsp. indica) and japonica (O. sativa L. subsp. japonica). Variation patterns in rice quality become more complex in the offspring produced from indica–japonica hybridization owing to interactions between inter-subspecies components. No QTLs underlying rice milled quality have been successfully cloned; hence, improving rice milled quality is a key dilemma, especially in the offspring of inter-subspecies hybridization. In this study, we analyzed variation patterns in rice milled quality caused by components introduced from indica, including both regulatory genes controlling influence factors (milled grain width and chalkiness) and the frequency of random introductions from the indica genetic backgrounds. Two populations (RILs and BILs) derived from indica–japonica hybridization were used. Both the frequency distribution value of indica components introduced (Di value) and grain-width regulatory genes (GS5 and GW5) had a significant impacted on variation in milled rice width (MRW), and their interaction accounted for the major MRW variance in RILs and BILs. The Di value had a significant impact on variation in chalkiness degree (C) in RILs and BILs; the regulatory gene Chalk5 also participated in the regulation of C in BILs. The Di value further influenced head rice rate (HR), with the average HR gradually decreasing as the Di value increased. Taken together, our results suggest that we should utilize backcrossing or multiple crosses to reduce the Di value in offspring produced by indica–japonica hybridization and promote the use of favorable genes during individual selections.

亚洲栽培稻（稻L.）分为两个亚种，籼稻（陆稻L.亚种籼稻）和粳稻（陆稻L.亚种粳）。由于种间成分之间的相互作用，在–粳杂交后代中，稻米品质的变异模式变得更加复杂。没有成功克隆出稻米品质的QTL。因此，提高稻谷碾米品质是一个关键的难题，尤其是在亚种间杂交的后代中。在这项研究中，我们分析了由in稻引入的成分引起的稻米品质变化模式，包括控制影响因素（碾磨的谷粒宽度和白垩度）的调节基因以及来自genetic稻遗传背景的随机引入的频率。两个群体衍生自（重组自交系和BILS）籼-粳稻杂交技术。两者的频率分布值籼稻组件中引入（Di值）和谷物宽度调节基因（GS5和GW5）对在精米宽度（MRW）的变化的影响显著以及它们的相互作用占重组自交系和BILS主要MRW方差。Di值对RIL和BIL中白垩度（C）的变化有重大影响；调节基因Chalk5也参与了BILs中C的调节。Di值进一步影响了稻米率（HR），平均HR随着Di值的增加而逐渐降低。总之，我们的研究结果表明，我们应该利用回交或多个杂交，以减少所产生后代的Di值籼-粳 杂交并促进个体选择过程中有利基因的使用。