ABSTRACT: Yield and growth criteria of irrigated and rainfed sunflower Helianthus annus and chickpea Cicer arientinum were studied under simulated climate change for Tabriz in Iran. Monthly average temperature and rainfall under doubling CO2 were predicted using Goddard Institute for Space Studies (GISS) and Geophysical Fluid Dynamics Laboratory (GFDL) models. The effects of climatic change on crop growth period, yield components and water requirements of those crops were evaluated by a crop simulation model (OSBOL). Based on GISS and GFDL predictions, with doubling CO2 concentration, mean annual temperature for Tabriz increased by 4.6 and 4.3°C, respectively. The results obtained by GISS showed that doubling CO2 will lead to an increase in mean temperature of 3.7°C, and a 40% increase in mean rainfall, during the first 5 mo of the year. However, GFDL predicted an increase of 4.7°C in mean temperature and a reduction of 12% in mean rainfall during the first 5 mo of the year. According to OSBOL under GDFL predictions, the period from sowing to maturity and harvest index were reduced by climate change, whereas yield, biomass and water requirement for irrigated sunflower were increased. The biomass for rainfed sunflower increased, while days to maturity and harvest index were reduced. Yield predictions of OSBOL based on GISS contrasted with those based on GFDL. Doubling CO2 caused a reduction in days to maturity, biomass, yield and water requirements for irrigated chick pea. The number of days to maturity for rainfed chickpea was reduced and harvest index, biomass and yield were increased due to climate change.

Keywords