Agroclimatic models for prediction of growth and yield of sunflower (Heuanthus annus L.)

Three agro climatic models based on Growing Degree Days (GDD), Heliothermal units (HTU) and Photothermal units (PTU) were evaluated for prediction of growth and yield of sunflower. Heat use efficiency (HUE) was also characterized for production of biomass and seed yield. Field experiments were conducted using two cultivars of sunflower crop, viz: cv. PSFH 118 and cv. SH 3322 during two consecutive Rabi seasons of 2003–04 and 2004–05 at Ludhiana. Leaf area development, dry matter accumulation and seed yield were correlated with agroclimatic indices of GDD, HTU and PTU. Significant regression relationships were observed for seed yield, leaf area index (LAI) and dry matter accumulation with the three agroclimatic indices. The prediction models can be applied to estimate crop growth and yield using daily information on temperature, photoperiod and sunshine duration during the crop season