Fine mapping and identification of a novel locus qGL12.2 control grain length in wild rice (Oryza rufipogon Griff.)
A wild rice QTL qGL12.2 for grain length was fine mapped to an 82-kb interval in chromosome 12 containing six candidate genes and none was reported previously.
Grain length is an important trait for yield and commercial value in rice. Wild rice seeds have a very slender shape and have many desirable genes that have been lost in cultivated rice during domestication. In this study, we identified a quantitative trait locus, qGL12.2, which controls grain length in wild rice. First, a wild rice chromosome segment substitution line, CSSL41, was selected that has longer glume and grains than does the Oryza sativa indica cultivar, 9311. Next, an F2 population was constructed from a cross between CSSL41 and 9311. Using the next-generation sequencing combined with bulked-segregant analysis and F3 recombinants analysis, qGL12.2 was finally fine mapped to an 82-kb interval in chromosome 12. Six candidate genes were found, and no reported grain length genes were found in this interval. Using scanning electron microscopy, we found that CSSL41 cells are significantly longer than those of 9311, but there is no difference in cell widths. These data suggest that qGL12.2 is a novel gene that controls grain cell length in wild rice. Our study provides a new genetic resource for rice breeding and a starting point for functional characterization of the wild rice GL gene.
We thank Shijia Liu, Liangming Chen, Xi Liu, and Yunlu Tian in Nanjing Agricultural University, China, for their assistance in field management at Nanjing experimental station. We thank Shelley Robison, PhD, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.
This study was supported by a Grant from the National Natural Science Foundation of China (No. 31471471), the National Key Research and Development Program of China (2016YFD0100101), and the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Science to Weihua Qiao.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
The authors declare that this study complies with the current laws of the countries in which the experiments were performed.
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