Association of Agrometeorologists

Quantification of growth and yield of oilseed Brassica using thermal indices under semi-arid environment

A.K. SRIVASTAVA, TARUN ADAK and N.V.K. CHAKRAVARTY

Field experiments were carried out at IARI research farm, New Delhi representing semi-arid climatic condition, to evaluate the growth and yield of oilseed Brassica using thermal indices. Two cultivars of Brassica juncea viz., Pusa Jaikisan and Varuna, widely grown in north and north-western parts of the country, were sown on ten different dates from 1st October to 3rd December at weekly interval. Three widely used thermal indices viz, growing degree days (GDD), heliothermal units (HTU) and photothermal units (PTU) were computed up to maximum biomass production in both the seasons. It was observed that GDD was able to explain variation in biomass, seed yield and oil content to the tune of 75, 66 and 78 per cent while PTU could explain 73, 66 and 77 per cent variations respectively. The yields and oil content of these two cultivars were highly influenced by the differential thermal environment and delay of sowing; decreased seed yield and oil content significantly.

Thermal indices, GDD, HTU, PTU, HUE seed yield, oil content and Brassica.