Impact of Time Trend on Weighted Average Age of Some Irrigated Bread Wheat Varieties and its Economic Analysis

In generally, important factors in substitution of varieties are including increasing of yield, improvement of quality and avoid of decreasing of yield varieties versus biotic and abiotic stress. The objectives of this study were to: determine of Weighted average age of wheat varieties and comparison with other countries, determine to effect and correlation between time trend with weighted average ageof varieties and investigation of profitability of irrigated bead wheat varieties with different origins. This study carried out in 2016 for irrigated bead wheat varieties planted in 2004-2016. Data are collected from Deputy of Agronomy in Ministry of Jihad-e-Agriculture and Certified and Register of Seed and Plant Institute. The methodology of this research were time trend linear regression analysis, weighted average ageindexes, coefficient of correlation and profitability indicators (Net present value, Benefit-cost ratio and Internal rate of return). According to the results, Estimated coefficient of Time Trend on weighted average ageof varietieswas positive and 0.091 and 0.46 and significant.. Benefit-cost ratio(BCR) and Internal rate of return(IRR) for Ghonbad variety with national originwas estimated 5.5 and 41.9%.BCR and IRR for Sirvan variety with international originwas estimated 6.1 and 54.3%. Thus, time trend variable was one of important factor on Weighted average ageof varieties. For more effecting of varieties on farmer’s income based on economic results recommended selecting of proper variety with high profitability, preparation of timely and adequate for improved seed varieties in during of age varieties by institutes.