Characteristics and coordination of source-sink relationships in super hybrid rice

This paper discusses the characteristics of source and sink for super hybrid rice and how to coordinate its source-sink relationships for high-yielding cultivation. It is known that super hybrid rice possesses a higher net photosynthetic rate than non-hybrid rice because of its higher grain-leaf area ratio, better stomata traits and less midday depression. However, the sink of super hybrid rice remains large due to its large and numerous spikelets. Furthermore, the relocation of assimilates is smooth in super hybrid rice because of its well-developed vascular structure. However, due to the very large sink of super hybrid rice, it is relatively inefficient in supplying of assimilate products to spikelets, in particular to inferior spikelets. Therefore, reducing the discrepancy between source and sink in super hybrid rice is essential for developing high-yielding cultivation. This can only be achieved by planting cultivars adapted for local environments, raising strong seedling, setting up populations with a high photosynthetic efficiency for increasing the supply of source, and improving the field management in filling stages to the duration of supply of photosynthate to grains.