Grain size is a major determinant of grain yield and quality in rice (Oryza sativa), and was therefore an important selective target during domestication and breeding (Fitzgerald et al., 2009) (Takano-Kai et al., 2009). In the past few decades, a dozen grain size-related QTLs/genes have been cloned (Huang et al., 2013, Zuo and Li, 2014). Pyramiding grain size QTLs to breed high-yielding and high-quality rice varieties has proved to be a great success. For example, by pyramiding the nonfunctional alleles gs3 and gw8 in line HJX74, Wang et al. (2012) converted a line with short and wide grains into one with slender grains and substantially improved grain quality. By pyramiding the GW7 allele from TFA and gs3, Wang et al. (2015) developed new high-yielding indica hybrid rice varieties with simultaneously improved yield and grain quality. Thus, it is of considerable importance to identify more grain size QTLs to facilitate further improvement in rice yield and quality.
籽粒大小是决定水稻产量和品质的主要因素，因此，在驯养和繁殖过程中是一个重要的选择性目标(Fitzgerald et al., 2009) (Takano-Kai et al., 2009)。在过去的几十年中，已经克隆了十几个与籽粒大小相关的QTLs/基因(Huang et al., 2013, Zuo and Li, 2014)。聚合多个调控籽粒大小的QTL来培育高产优质水稻品种，已被证明获得了巨大的成功。例如，通过聚合HJX74中功能缺失的gs3和gw8，Wang(2012)等人将一个籽粒短而宽的株系改良为细长粒，显著提高了稻谷品质。通过聚合gs3和TFA中的GW7，Wang(2015)等人成功培育一个高产籼稻杂交稻组合，产量和品质同时得到改良。因此，鉴定更多的调控籽粒大小的QTL，对于进一步提高水稻产量和品质具有重要意义。