National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
J Genet Genomics. 2012 Jul 20;39(7):325-33. doi: 10.1016/j.jgg.2012.03.001. Epub 2012 Mar 21.
Rice grain shape, grain length (GL), width (GW), thickness (GT) and length-to-width ratio (LWR), are usually controlled by multiple quantitative trait locus (QTL). To elucidate the genetic basis of extremely large grain shape, QTL analysis was performed using an F(2) population derived from a cross between a japonica cultivar 'JZ1560' (extremely large grain) and a contrasting indica cultivar 'FAZ1' (small grain). A total number of 24 QTLs were detected on seven different chromosomes. QTLs for GL, GW, GT and LWR explained 11.6%, 95.62%, 91.5% and 89.9% of total phenotypic variation, respectively. Many QTLs pleiotropically controlled different grain traits, contributing complex traits correlation. GW2 and qSW5/GW5, which have been cloned previously to control GW, showed similar chromosomal locations with qGW2-1/qGT2-1/qLWR2-2 and qGW5-2/qLWR5-1 and should be the right candidate genes. Plants pyramiding GW2 and qSW5/GW5 showed a significant increase in GW compared with those carrying one of the two major QTLs. Furthermore, no significant QTL interaction was observed between GW2 and qSW5/GW5. These results suggested that GW2 and qSW5/GW5 might work in independent pathways to regulate grain traits. 'JZ1560' alleles underlying all QTLs contributed an increase in GW and GT and the accumulation of additive effects generates the extremely large grain shape in 'JZ1560'.
水稻粒形、粒长（GL）、粒宽（GW）、粒厚（GT）和长宽比（LWR）通常受多个数量性状位点（QTL）控制。为了阐明特大粒形的遗传基础，利用来源于粳稻品种 'JZ1560'（特大粒）和籼稻品种 'FAZ1'（小粒）杂交的 F2 群体进行了 QTL 分析。在七个不同的染色体上共检测到 24 个 QTL。GL、GW、GT 和 LWR 的 QTL 分别解释了总表型变异的 11.6%、95.62%、91.5%和 89.9%。许多 QTL 控制不同的粒形性状表现出多效性，对复杂性状相关性有贡献。先前已克隆控制 GW 的 GW2 和 qSW5/GW5，与控制 GW 的 qGW2-1/qGT2-1/qLWR2-2 和 qGW5-2/qLWR5-1 具有相似的染色体位置，应该是正确的候选基因。与携带两个主要 QTL 之一的植株相比，GW2 和 qSW5/GW5 基因聚合的植株 GW 显著增加。此外，GW2 和 qSW5/GW5 之间没有观察到显著的 QTL 互作。这些结果表明，GW2 和 qSW5/GW5 可能通过独立途径调控粒形性状。所有 QTL 下的 'JZ1560' 等位基因均导致 GW 和 GT 增加，累加效应的积累产生 'JZ1560' 中的特大粒形。
