Salicylic acid priming effects on some morphological traits of a cowpea cultivar (Vigna unguiculata) under water defificit at podding stage.

In order to evaluate seed priming effects by salicylic acid on some morphological traits of a cowpea (Vigna unguiculata) cultivar, “Parastou”, under water deficit condition at podding stage, an experiment was carried out in Research farm of Zanjan university in 2008 -2009 using a spilt block design and three replications. Applied factors were drought stress as main factor in two levels (normal irrigation, application of water deficit at podding stage) and priming with salicylic acid as subfactor in five levels (0, 900, 1800, 2700, 3600 μM). Analysis of variance showed that the effect of irrigation was significant on all traits except plant height. Salicylic acid had a significant effect on all traits. Means comparison showed that number and dry weight of leaf and leaf area, seed yield and yield components decreased in treatments with water deficit compared with treatments with normal irrigation. These traits increased in salicylic acid primed seeds compared with control seeds. Seed primed with 2700 μM salicylic acid had desirable situation for all traits compared to treatments with normal irrigation and those with deficit condition at podding stage. Primed seeds with 2700 μM salicylic acid had higher emergence index, emergence percentage and leaf area. Because of decreasing time of flowering and time of podding, seed yield increased in both irrigation conditions. So seeds primed with 2700 μM salicylic acid had the highest seed yield (4424 and 2475 kg.ha in regular irrigation and water stress at podding stage, respectively).