The relationship between climatic variables with yield and duration of growth stages of corn and irrigated wheat in Hasan Abad, Darab, Fars Province

Climate is one of the main determinant factors in agricultural production. This study aimed to investigate the relationship between climate variables with yield and duration of corn and wheat growth stages. For this purpose, the data related to, the number of days of growth stages, together with climate variables including minimum, average and maximum temperatures, minimum ground temperature, sunshine hours, evaporation, minimum, average and maximum relative humidity, relative humidity at 09 and 15 GMT, the total precipitation, the number of rainy days with 0.1, 1 and 5 mm and more for a 19-year period between 1995-96 and 2013-14 were collected from agrometeorological research station in Darab, Fars Province. Statistical analyses were performed using Pearson correlation coefficient and regression equations. According to the results of this study, evaporation and maximum relative humidity had the highest correlation with the length of the entire corn growth season (correlation coefficient of 0.807). For wheat, the results showed that the highest correlation was observed between the minimum and maximum relative humidity and the length of the growth period at the heading stage (correlation coefficient of 0.867). In addition, the results revealed that the highest impact of climate variables on corn yield occurred at the three leaf stage, so that at this growth stage, the minimum and average of  relative humidity had the highest significant correlation at the 1% probability level with yield (correlation coefficient of 0.890). For wheat, the highest correlation was observed between yield and relative humidity at 09 GMT at the ripening stage. In conclusion, the results showed a good accuracy of the statistical models in estimating the growth period and yield of corn and wheat.