AUTHOR=Xue Pao , Chen Yu-yu , Wen Xiao-xia , Wang Bei-fang , Yang Qin-qin , Gong Ke , Kang Yi-wei , Sun Lian-ping , Yu Ping , Cao Li-yong , Zhang Ying-xin , Zhan Xiao-deng , Cheng Shi-hua 

TITLE=Dissection of Closely Linked Quantitative Trait Locis Controlling Grain Size in Rice

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 12 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.804444

DOI=10.3389/fpls.2021.804444

ISSN=1664-462X

ABSTRACT=Grain size is a key constituent of grain weight and appearance in rice. However, insufficient attention has been paid to the small-effect QTLs on grain size. In the present study, residual heterozygous populations were developed for mapping two genetically linked small-effect QTLs for grain size. After genotyping and phenotyping of five successive generations, qGS7.1 was dissected into three QTLs and two were selected for further analysis. qTGW7.2a was finally mapped into a 21.10-kb interval containing four annotated candidate genes. Transcript levels assay showed that the expression of candidates LOC_Os07g39490 and LOC_Os07g39500 were significantly reduced in the NIL-qTGW7.2aBG1. The cytological observation indicated that qTGW7.2a regulated grain width through controlling cell expansion. Using the same strategy, qTGW7.2b was fine mapped into a 52.71-kb interval containing eight annotated candidate genes, showing a significant effect on grain length and width with opposite allelic directions but little on grain weight. Our study provides new genetic resources for yield improvement and fine-tuning of grain size in rice.