Impacts of Climate Factors on Risk of Yield of Irrigated Wheat Lines in Breeding Researches

Today, climatic change is known as a key and effective variable on growth in crop yield. This aimed at determining the effect of environmental factors, time trend and places variables on improved genetic of irrigated bread wheat lines in breeding program in different research stations of Iran. The required panel data were collected from 22 locations in breeding program of irrigated bread wheat during 1995-2014. The study was conducted in a stochastic production function of Just and Pope. According to the results, the impact of time trend on mean yield and risk variance of the irrigated wheat lines was estimated positive and significant, improving the annual mean yield by 29 kg/ha. The impact of released year on mean and variance of the irrigated wheat lines was estimated positive and statistically significant as well. The impacts of mean temperature (0C) and amounts of raining (mm) in different seasons on mean and variance of the irrigated wheat lines were estimated significant.