Influence of different light intensities on specific leaf weight, stomatal density photosynthesis and seed yield in soybean

Abstract

The availability of low light intensity due to shading is the critical factor in determining soybean yield in intercropping system. An experiment was conducted to search genotypes tolerant to low light intensity, which can be better grown for intercropping system. The objective of this study was to determine the influence of different light regimes (35%, 50%, 75% of normal light and normal light) on physiological traits such as specific leaf weight, stomatal density, photosynthesis, total biomass and seed yield of soybean genotypes. Different shading conditions were created using shading net of 35, 50 and 75% to cut the natural solar radiation received by plants to identify genotypes tolerant to low light intensity. One set of plants was also grown under natural conditions without any shading net. Significant negative effect of low light intensity was observed on specific leaf weight, stomatal density and photosynthesis in soybean genotypes. Among the shading conditions, the average seed yield was maximum (31.5 g/pl) in plants grown under control condition. When plants were grown under 35% shading net the seed yield was declined by 37% (20.0 g/pl). However, severe reduction to the extent of 64 and 76% was observed when plants were grown under shading net of 50% (11.2 g/pl) and 75% (7.7 g/pl), respectively as compared to plants grown under control condition. Therefore, the effects of shade on crops should be considered when trying to increase the productivity of an intercropping system.