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The present study aimed to investigate the effect of different shade treatments (0%, 35%, 50% and 75%) on physiological traits and yield attributes of two soybean genotypes namely JS 97‐52 and JS 95‐60. The results clearly showed that plants which were grown under control conditions exhibited the highest values for specific leaf weight, chlorophyll content, leaf thickness and stomatal density, whereas the lowest values were observed in plants subjected to 75% shading. Moreover, a significant reduction in photosynthetic rate, stomatal conductance and electron transport rate was observed with decreased solar radiation. Performance index, fluorescence area, Fv/Fo, Fo/fm, ABS/CSo, DIo/CSo, TRo/CSo and ETo/CSo were also reduced under heavy shade. Seed yield was reduced by 24%, 47% and 62% in JS 97‐52 and by 51%, 82% and 92% in JS 95‐60 under 35%, 50% and 75% shading, respectively, compared to the control conditions. Therefore, to enhance crop productivity under intercropping, the effects of shade should be taken into consideration. [ABSTRACT FROM AUTHOR]

Elevated temperature and water deficit are the major abiotic factors restricting plant growth. While in nature these two stresses often occur at the same time; little is known about their combined effect on plants. Therefore, the main objective of the current study was to observe the effect of these two stresses on phenology, dry matter and seed yield in soybean. Two soybean genotypes JS 97-52 and EC 538828 were grown under green-house conditions which were maintained at different day/night temperatures of 30/22, 34/24, 38/26 and 42/28 °C with an average temperature of 26, 29, 32 and 35 °C, respectively. At each temperature, pots were divided into three sets, one set was unstressed while second and third set were subjected to water stress at vegetative and reproductive stage, respectively. As compared to 30/22 °C increase in temperature to 34/24 °C caused a marginal decline in leaf area, seed weight, total biomass, pods/pl, seeds/pl, harvest index, seeds/pod and 100 seed weight. The decline was of higher magnitude at 38/26 and 42/28 °C. Water stress imposed at two growth stages also significantly affected dry matter and yield. The highest average seed yield (10.9 g/pl) was observed at 30/22 °C, which was significantly reduced by 19, 42 and 64% at 34/24, 38/24 and 42/28 °C, respectively. Similarly, compared to unstressed plants (11.3 g/pl) there was 28 and 74% reduction in yield in plants stressed at vegetative and reproductive stage. Thus, both temperature and water stress affected the growth and yield but the effect was more severe when water stress was imposed at higher temperatures. JS 97-52 was more affected by temperature and water stress as compared to EC 538828. Though drought is the only abiotic factor that is known to affect the water status of plants, but the severity of the effect is highly dependent on prevailing temperature. [ABSTRACT FROM AUTHOR]