Analysis and Simulation of Impact of Light and Temperature on Rice Tillering

In order to investigate the effects of light and temperature on rice tillering dynamics in tillering stage and validate the light and temperature effect equation in current dynamic tillering models. We performed two-year field-seeding experiments (2012–2013) using two indica two-line hybrid rice cultivars, Lingliangyou 268 and Liangyoupeijiu. And we collected the observation data in tillering. To fit Richards equation for retrieving characteristic parameters related to the maximum tiller density, average growth rate of tillers, and duration of the growing period. Moreover, we analyzed the relationships between all these characteristic parameters and average data of light, temperature and climatic variables during the growing period for each rice cultivar. Based on the relationships we established co-effect equations for the growth rate of tillers and maximum tiller density as a function of co-effect of light and temperature. The new co-effect functions for each cultivar were substituted for the effect functions of light and temperature in a widely used dynamic tillering model to simulate the dynamic tillering in tillering stage. Finally, valida第 1期 王萌萌等: 光温要素对水稻群体茎蘖增长动态影响的分析及模拟 83 tion and comparison were carried out for the models applied observation data in tillers period. The result showed that the light and temperature affected crop growth in tillering period. The growth rate of tillers and the actual maximum tiller density positively correlated with the two meteorological factors significantly. Compared with current dynamic tillering model, the model with the established co-effects of light and temperature functions decreased the error significantly in simulating the growth dynamics of tillers. The simulated rice tillering was well consistent with the observed in both growth rate and maximum tiller density for both rice cultivars. However, the discrepancy could also be found in some seeding periods and validation samples, which may be caused by rice adaptability to different light and temperature environments. In conclusion, the validation and improvement of the light and temperature co-effect functions put forward in this study can be used further for understanding the effects of light and temperature factors on rice tillering and improving dynamic tillering models in the future.