Relative efficiency of elite restorers in rice breeding and their low light adaptability

Twenty-six selected restorers with maturity duration ranging from 123 to 140 days were field tested for their bioproductivity and yield under normal (L) and induced lowlight (S) (50% normal light from 40d to harvest) during dry season. At flowering, the total dry matter production was highest in ARC 11353 and Indira in L and Bhavani, IR 54 and Swarnaprabha in S. IR 4422-480 recorded a significantly high Leaf Area Index (LAI) in L but Swarnaprabha and Ptb 10 under S. ARC 11353 recorded the highest Specific Leaf Weight (SLW) in both the light regimes. At harvest, Swarnaprabha and ARC 11353 recorded highest dry matter as well as grain yield under S. The adverse effect of lowlight was more on yield than on total dry matter production at flowering and harvest. The range in Shade Index (SI) for yield is 14 (Suween 294) to 74 (ARC 11353). ARC 11353 was superior in SI in both Total Dry Matter (TDM) (barring Swarnaprabha) and yield indicating its efficiency and adaptability to lowlight conditions. The yield under S positively associated with LAI at flowering (r= 0.576**), TDM at flowering (r=0.647**) and harvest (r=0.832**) and with Harvest Index (HI) (r=0.851**). However, yield under L is related with HI only (r=0.837**), presumably LAI and TDM at flowering, TDM and HI at harvest are effective for grain yield under S while HI is the major trait for yield under L.