Source-sink interrelationships in lowland rice

Summary

Present studies indicate that leaf could determine the degree of plants' performance and condition the level of unfilled spikelets. Environmental constraints like low light intensity itself can considerably affect the function of the leaf resulting in greater proportion of unfilled spikelets or sterility, which appears to be a post-fertilization problem. This suggests that ‘source’ (leaf) is unable to cater to the requirements of the panicle. Further, the LAI studies have revealed the existence of a wide gap between spikelet production and grain filling. Panicle-tailoring studies pointed out that sterility could be reduced if panicle size is reduced. In the light of all these evidences, it was concluded that ‘source’ is limiting at the present level of evolution in rice under Indian conditions.