Abstract

                                Irrespective of varieties, low light intensity significantly increased the plant height, leaf area index (LAI) and total leaf chlorophyll content while significant reduction was evident in respect of total dry matter, panicle number, spikelet number, filled grains and grain yield. It was considered that low light intensity during samba/thalaci season, appearing particularly from panicle initiation to harvest was an important constraint for higher productivity since yields as low as 3.19 to 4.28 tha were recorded with varieties which yielded 5.00 to 5.84 tha under normal light intensity conditions. Among several varieties, Ponni appeared to be more tolerant with least reduction in grain yield (15.9%) under low light intensities thus more suitable for samba/thaladi season followed by White Ponni, Co 43 and IR 20.

Key words : Rice, Low light, Productivity