A field experiment was conducted at Hi-Tech Horticultural Unit, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during rabi, 2015-16 to study physiological responses of tomato cultivars viz., STH-801, STH-510 and STH-39to three different protected conditions viz., polyhouse, shade house with 35 and 50 per cent shade net. Among the different growing conditions, polyhouse recorded significantly lowest plant height (80.00, 114.27 and 172.27 cm at 45 and 75 DAT and

more »

... arvest, respectively), higher light transmission ratio (36.54, 22.92 and 19.17 % 45 and 75 DAT and harvest, respectively), canopy temperature (27.85, 35.16 and 37.85 °Cat 45 and 75 DAT and harvest, respectively), specific leaf weight, photosynthetic rate (20.59, 17.48 and 15.67µmol CO 2 m -2 s -1 at 45 and 75 DAT and harvest, respectively) which resulted in higher yield (2.87 kg plant -1 and 97.02 t ha -1 ) as compared to shade house with 35 and 50 per cent shade net. The tomato hybrid, STH-801 was found to have significantly highest canopy temperature, specific leaf weight (7.97, 9.22 and 9.29 mg cm -2 at 45 and 75 DAT and harvest, respectively), photosynthetic rate, yield (2.43 kg p -1 and 82.17 t ha -1 ) as compared to STH-510 and STH-39. The tomato hybrid, STH-801 showed optimum height, higher light transmission ratio, canopy temperature, specific leaf weight, photosynthetic rate and yield under polyhouse condition. K e y w o r d s Light transmission ratio, Photosynthetic rate, Polyhouse, Shade house, Tomato