Effect of climatic variation on yield of sesame (Sesamum indicum L.) at different dates of sowing

Although experiments have previously been carried out to determine the opti mum sowing time of sesame, very few attempts have been made to determine th e effects of macro and micro climatic variation on yield. Thus a field expe riment was conducted at the University Research Farm, Bidhan Chandra Krishi Viswavidyalaya, Kalyani, India on an Entisol (alluvial, sandy loam) in the summer seasons of 1996 and 1997 to assess the effects of macro and micro c limatic variations on yield of sesame for various dales of sowing. The numb er of seeds per capsule of sesame was highest in the crop sown on 19 Februa ry, although up to the is April sowing their was no significant variation. Then was no appreciable variation in thousand-seed weight with date of sowi ng. Crops sown on 19 February and 1 March produced statistically similar yi elds. The average reduction ill yield of sesame was 78.5 and 213 %, respect ively, for crops sown on 10 February and 28 April, compared with the crop s own on 19 February. The cultivar Rama produced higher yields than B-67 and Kanke-1. Ambient temperature above 30 degreesC up to 100 % flowering had a direct positive effect on sesame yield. Crop exposure to 60-70, 70 80 and 8 0 % relative humidity up to 100 % flowering had a direct negative effect. T emperature profile at 50 days after emergence (DAE), relative humidity at 6 0 DAE, and photosynthetically active radiation (PAR) at 30 and 30 DAE withi n the crop canopy had direct positive effects on yield. Regression models s uggested that temperature profile and PAR within the crop canopy produced 7 2 and 35 % variation in yield, respectively.