Higher radiation use efficiency and photosynthetic characteristics after flowering could alleviate the yield loss of Indica‐Japonica hybrid rice under shading stress
Shang, C and Guo, Z and Chong, H and Xiong, X and Deng, J and Harrison, MT and Liu, K and Huang, L and Tian, X and Zhang, Y, Higher radiation use efficiency and photosynthetic characteristics after flowering could alleviate the yield loss of Indica‐Japonica hybrid rice under shading stress, International Journal of Plant Production, 16 pp. 105-117. ISSN 1735-6814 (2022) [Refereed Article]
The yield advantage of indica-japonica hybrid rice over indica hybrid rice has been studied extensively. However, little information is available about the growth characteristics and yield performance of I-JR under shading stress. A 2-year field experiment was conducted to compare the grain yield, total dry weight, and radiation use efficiency of I-JR (Yongyou 1540 and Yongyou 538) and IR (Y-liangyou 900 and Quanyouhuazhan) under shading stress after flowering. The grain yields of I-JR and IR were reduced by 45.0% and 59.2% caused by shading averaged across two years. Shading significantly affected grain filling percentage of I-JR and IR, and decreased by 44.5% and 55.3% compared with the normal conditions. The TDW and distribution of panicle were significantly reduced by shading, but the apparent exportation and apparent export rate were increased. Under shading stress, the RUE during the grain filling stage was decreased by 26.5% (I-JR) and 71.7% (IR). The correlation analysis showed that grain yield was significantly correlated with RUE, intercepted radiation and TDW in I-JR. In addition, shading significantly reduced the specific leaf weight, net photosynthetic rate and stomatal conductance in leaves, and the negative effects were higher in IR than in I-JR. Overall, our results showed I-JR had significantly higher grain yield than IR under shading stress, which was attributed to its higher grain filling percentage and total dry weight resulted from higher RUE and leaf photosynthetic characters during grain filling stage as compared with IR.