Investigation of the Limiting Factors of Wheat Seed Yield in the Eastern Region of Kerman

To investigate and determine the limiting factors of wheat grain yield and the contribution of each of these factors in creating wheat grain yield gap, this study was conducted based on the CPA method (comparison performance analysis) in the eastern part of Kerman. Fifteen farms in each at Bam, Narmashir and Fahraj cities, (5 farms in each city) studied for two years (2017-2018 and 2018-2019). In this study, all information related to management, climate and agricultural traits (including 45 variables) were measured and recorded. Using multiple regression method, the relationship between wheat yield and all variables were examined step by step. A production model was determined for management and climate factors. The results showed that there was a gap between the actual yield (farmers' yield) and the potential yield (attainable yield) of 2347.98 kg.ha-1. Irrigation rate, consumed nitrogen fertilizer, spike density and late planting were 51.1%, 36.4%, 7.9% and 4.5%, respectively, involved in creating yield gap. Among the farms studied, the farm located in Firoozabad Fahraj with 6272 kg.ha-1 seed yield had the highest seed yield and the farm located in Dolatabad Fahraj with 1116 kg.ha-1 had the lowest grain yield. According to this research, it seems that with proper management of farms and optimization of limiting factors (Irrigation rate, consumed nitrogen fertilizer, spike density and late planting) wheat yield in Bam, Narmashir and Fahraj regions can be increased by 2347.98 kg.ha-1 as compared to that of the current yields of the farmers, studied.