The solar radiation-related determinants of rice yield variation across a wide range of regions

The information available on the environmental and plant characteristics that contribute to rice yield variation over a wide range of regions would be useful for understanding the generalized determinants of rice yield. In this study, we extracted the data (n = 107) of grain yield, biomass production, harvest index, intercepted radiation, radiation use efficiency (RUE), incident radiation and intercepted percent from 5 published studies conducted in 6 locations across 3 countries and evaluated the relationships between the parameters. A very large variation in grain yield, from 3.31 to 16.50 t ha−1, was observed. About 73% and 6% of the yield variation was explained by biomass production and harvest index, respectively. Biomass production was strongly positively related to intercepted radiation. However, intercepted radiation would be difficult to further increase because it was related much more closely to incident radiation than to intercepted percent. Although RUE did not explain the variation in biomass production, it varied by nearly two fold (0.99-1.88 g MJ−1). Our study highlights the need for a comprehensive understanding of the various aspects of RUE in rice.