Induced low light (50% sun light) from 40 days after planting to harvest in field reduced tiller number, stem weight ratio (SWR), total dry matter, photosynthetic potential and NAR and increased plant height, leaf area index and leaf chlorophyll content at lowering among 13 early high yielding rice varieties, in both dry and wet seasons. At harvest, the dry matter, grains/m2 and grain yield were reduced by about 50% and the spikelet sterility increased by 1.5 fold. Swamaprabha (Culture-1907) from Kerala consistently recorded highest yield in both the seasons even under induced low light. SWR and photosynthetic potential showed high association with yield under low light and hence useful as selection indices for low light adapted and productive rice varieties.
