Abstract
Chickpea (Cicer aeritinum), bottlegourd (Lagenaria siceraria), and sweetpotato (Ipomoea batatus) were evaluated at 100, 75, 50, and 25% available photosynthetically active radiation (PAR). In chickpea, plant height and branch number per plant were found to be higher at reduced light levels. But other parameters except 100-seed weight showed superior performance at 100% PAR, although the differences between 100 and 75% PARs were similar (P > 0.05). In bottlegourd, fruit number, fruit length, and fruit yield showed almost similar trends where respective values at 100 and 75% PARs were similar, but both values were significantly (P < 0.05) higher than the other light treatments. Fruit weight was the highest at the full light and then steadily declined as light level decreased. In sweetpotato, vine length increased as light levels decreased, whereas number of leaves, branches, and tubers per plant decreased. But tuber weight per plant and tuber yield per hectare were the highest at 75% light treatment, followed by 100, 50, and 25% PAR treatments. It was interesting to note that all parameters of sweetpotato measures were similar from full PAR to 50% reduced PAR. The relationship between PAR and yields of tested crops showed linear relationships in chickpea and bottlegourd, and quadratic polynomial relationship in sweetpotato.
