Meta-analysis of seed priming effects on seed germination, seedling emergence and crop yield: Iranian studies

A large body of research has documented the effect of seed priming ongermination, emergence and crop yield. In such research, seed priming has beenfound to have a positive, negative or no effect. Meta-analysis can help tosummarize and interpret a collection of experiments. The aim of this study was toconduct a meta-analysis to synthesize published data from studies addressing theeffect of seed priming in Iran. Our results indicated that seed priming profoundlyinfluences germination (rate or percentage), seedling emergence (rate orpercentage) and crop yield. Among the studied traits, the crop yield increased themost (+28%), followed by the seedling emergence percentage (+19%), thegermination rate (+17%), the seedling emergence rate (+15%) and the germinationpercentage (+4%). In general, hormonal priming was the best seed primingtreatment. This was followed by hydropriming and osmopriming. The best primingdurations were 12-24 h for the germination percentage (+14%), longer than 24 hfor the germination rate (+16%), shorter than 24 h for the seedling emergence rate(+10 to + 14%) and the percentage (about +11%) and shorter than 12 h for the cropyield (+26%). Seed priming significantly increased in all of the traits of eudicotsand monocots, except for the germination percentage in monocots. The differenceswere significant between the monocot and eudicot species in the germination stage.The differences became insignificant in the seedling emergence and crop yield.Finally, it was concluded that hydropriming is a practical treatment. This is due toits low cost and beneficial effects. We additionally concluded that durations shorterthan 12 h are the most effective for this priming.