Dissecting the Genetic Basis of Grain Shape and Chalkiness Traits in Hybrid Rice Using Multiple Collaborative Populations
Junyi Gong+, Jiashun Miao+, Yan Zhao, Qiang Zhao, Qi Feng, Qilin Zhan, Benyi Cheng, Junhui Xia, Xuehui Huang*, Shihua Yang* and Bin Han*
Molecular Plant
, 2017,10:1353-1356.
10.1016/j.molp.2017.07.014
Abstract
Through the efficient use of heterosis, hybrid rice varietiesgenerally have higher grain yield potential than inbred varieties.With the significant advantage in grain yield, over the past30 years approximately half of China’s total rice-growing areais planted with rice hybrids. However, grain quality has nowbecome one of the most important targets in hybrid ricebreeding for meeting consumer demands. Grain shape andchalkiness are two important components of rice grain quality,in which slender grains (typically, grain length-to-width ratio>3) with low chalkiness are preferred by most consumers ofhybrid rice. Especially, grain chalkiness not only bringsdown the grain appearance but also has a negative influenceon milling and cooking properties. Previous studies havecharacterized several important genes controlling grain shapetraits, e.g., GS3 (Fan et al., 2006) affecting grain length,qSW5/GW5/GSE5 (Shomura et al., 2008; Duan et al., 2017;Liu et al., 2017) affecting grain width, GL7/GW7 (Wang et al.,2015a, 2015b) shaping both grain length and grain width.By contrast, only a few quantitative trait locus (QTLs)responsible for grain chalkiness have been finely mappedand functionally characterized. Chalk5, which encodes avacuolar H+-translocating pyrophosphatase, is the first clonedand functionally characterized gene that controls rice grainchalkiness (Li et al., 2014). However, the genetic architectureof the two traits, grain shape and grain chalkiness, in hybridrice remains unclear.