The effect of climate change on phenological traits of chickpea (Cicer arietinum L.) under rainfed and irrigated conditions in Gonbad

Chickpea is the third most important cereal crop in the world after beans and peas. European scientists found that studying 542 plant species in 26 European countries, including 125,000 time series, found that in 78% of the time between 1971 and 2000, the rate of development increased due to rising temperatures and shorter stages. The shortening of the growth period caused by the increase in temperature in most crops reduces yield because it absorbs less radiation and has less time for dry matter accumulation. The purpose of this study was to identify the effects of climate change on phenological traits of chickpea in Gonbad city in order to adapt and improve yield for future conditions.Materials and MethodsFirst, meteorological data from the Dome Synoptic Weather Station from 1993 to 2017, including daily data on maximum and minimum temperatures, sunshine hours and rainfall, and then processed and converted to DOY using the Srad -calc program (Soltani & Sinkler, 2012) Solar radiation was calculated based on sunny hours and days of the year. Then, new changes were made to the meteorological data based on climate change scenarios. The SSM-iLegume-Chickpea model was implemented for both rain and water conditions and each scenario. Planting type was selected according to the climatic conditions of the region, autumn and the type of free cultivar. Simulations For each rainfed and irrigated condition, three different planting dates (December, January and February) were selected and simulations were performed for 25 years (1993-2017). Results Planting date and climate change scenarios were significant at 1% level for all phenological traits in both rainfed and irrigated conditions, while the interaction effects of planting date and climate change except day to emergence were significant at 1% level. As the temperature rises in the future climate, the length of the phenological stages, ranging from day to flowering, day to pod start, day to physiological maturity, and day to harvest maturity will be reduced compared to normal conditions. Maximum decrease in phenology length was related to increase in temperature of 6°C and combined effects of doubling Co2 concentration, two percent decrease in precipitation and increase of 6°C under normal conditions, and minimum decrease in temperature increase scenario by 2°C. Co2 is a two percent decrease in recipitation and an increase of two degrees Celsius in both rainfed and irrigated conditions. Therefore, due to unchanged phenological stages under Co2 doubling scenarios and 2% reduction in rainfall compared to normal conditions, and reduction in phenological stages under the influence of temperature rise scenarios and similarity of the results of the temperature rise scenarios alone compared to the combined effects of Co2 doubling and 2% decrease in precipitation and an increase in temperature can be deduced that only an increase in temperature reduces the length of the phenological stages.ConclusionSimulation results in Gonbad city showed that increasing Co2 concentration in both rainfed and irrigated conditions and different planting dates had no effect on the phenological stages of chickpea but increasing temperature would significantly decrease the chickpea growth period, although this decrease in the length of chickpea growth is greater in the vegetative growth stage. As a result, the chickpea plant enters the reproductive stage faster, enjoys better temperature and humidity conditions in the reproductive stages, and causes premature and eventually evaporation of drought and late-season heat, and ultimately increases yield under conditions that will be dry. But delay in chickpea planting will shorten the chickpea growth period, depletion of available resources such as radiation, optimum humidity and temperature, dealing with end-season heat and drought, and ultimately yield loss.