Meta-Analysis of Some Effective Factors on Wheat Production In Iran

Meta-analysis is compressive science and statistical analysis of a large content statistical results of different studies in order to organization of findings. In this study, it was studied the effects of some agricultural operations on grain yield, biological yield and harvest index of wheat. The treatments included: soil tillage, nitrogen fertilizer, salt stress, hydro-priming, osmo-priming, hormo-priming, and physical priming which tested with Hedges method. Therefore, the studies that have control treatment and other treatments, after weighting of value of traits, effect size, and reaction relation and confidence range estimated. Meta-analysis results showed that nitrogen fertilizer caused 46, 32, and 27 percent increase in grain yield, biological yield, and harvest index respectively but traditional tillage and salt stress decreased grain yield, biologic yield, and harvest index. Tillage resulted 2, 5, and 11 percent reduction in grain yield, biologic yield, and harvest index respectively and also salt stress led to 8% and 7% decrease in biologic yield and harvest index, and a 35% reduction in grain yield. Outcomes also showed that hydro-priming, osmo-priming, hormo-priming have positive effects on grain yield, biologic yield, and harvest index, so that hydro priming increased biologic operation (23%), grain yield (16%) and harvest index (19%). Furthermore, osmo-priming effect has been a 30% increasing in biologic yield and it was to 50% and 59% in biologic operation and seed operation while this effect has caused the small amount of 1% increase in harvest index.