Grain shape is a factor affecting the stigma exsertion rate in rice

Quanya Tan; Songliang Chen; Zhenpeng Gan; Qimiao Lu; Zhenguang Yan; Guodong Chen; Shaojun Lin; Weifeng Yang; Jiao Zhao; Yuanyuan Ba; Haitao Zhu; Suhong Bu; Guifu Liu; Zupei Liu; Shaokui Wang; Guiquan Zhang

doi:10.3389/fpls.2023.1087285

Grain shape is a factor affecting the stigma exsertion rate in rice

Front Plant Sci. 2023 Jan 31:14:1087285. doi: 10.3389/fpls.2023.1087285. eCollection 2023.

Authors

Quanya Tan^{1

2}, Songliang Chen^{1

2}, Zhenpeng Gan^{1

2}, Qimiao Lu^{1

2}, Zhenguang Yan^{1

2}, Guodong Chen^{1

2}, Shaojun Lin^{1

2}, Weifeng Yang^{1

2}, Jiao Zhao^{1

2}, Yuanyuan Ba^{1

2}, Haitao Zhu^{1

2}, Suhong Bu^{1

2}, Guifu Liu^{1

2}, Zupei Liu^{1

2}, Shaokui Wang^{1

2}, Guiquan Zhang^{1

2}

Affiliations

¹ Guangdong Provincial Key Laboratory of Plant Molecular Breeding, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, China.
² Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China.

Abstract

Stigma exsertion rate (SER) is an index of outcrossing ability in rice and is a key trait of male sterile lines (MSLs) in hybrid rice. In this study, it was found that the maintainer lines carrying gs3 and gs3/gw8 showed higher SER. Single-segment substitution lines (SSSLs) carrying gs3, gw5, GW7 or gw8 genes for grain shape and gene pyramiding lines were used to reveal the relationship between grain shape and SER. The results showed that the grain shape regulatory genes had pleiotropic effects on SER. The SERs were affected by grain shapes including grain length, grain width and the ratio of length to width (RLW) not only in low SER background, but also in high SER background. The coefficients of determination (R²) between grain length and SER, grain width and SER, and grain RLW and SER were 0.78, 0.72, and 0.91 respectively. The grain RLW was the most important parameter affecting SER, and a larger grain RLW was beneficial to stigma exsertion. The pyramiding line PL-gs3/GW7/gw8 showed the largest grain RLW and the highest SER, which will be a fine breeding resource. Further research showed that the grain shape regulatory genes had pleiotropic effects on stigma shape, although the R² values between grain shape and stigma shape, and stigma shape and SER were lower. Our results demonstrate that grain shape is a factor affecting SER in rice, in part by affecting stigma shape. This finding will be helpful for breeding MSLs with high SER in hybrid rice.

Keywords: grain shape; outcrossing ability; pleiotropic effect; rice; stigma exsertion; stigma shape.

Grants and funding

This work was supported by grants from the Major Program of Transgenic New Variety Breeding of China (2014ZX08009-037B), from the National Natural Science Foundation of China (91435207, 32201841), and from the Major Science and Technology Research Projects of Guangdong Laboratory for Lingnan Modern Agriculture (NT2021001).