impact of methyl jasmonate on vegetative parameters and fruit yield of melon cv. ‘semsuri’

to investigate the effects of methyl jasmonate growth regulators on growth characteristics, fruit number and fruit yield of ‘semsuri’ melon, an experiment at the field of shahid bahonar university was conducted in summer 2012. melon (cv. ‘semsuri’) is widely cultivated in iran and therefore increasing the fruit yield and quality of this cultivar is necessary. some growth regulators including methyl jasmonate (mj) may improve growth and development of plants when applied at appropriate low concentrations. thus, a complete random block experiment at the research field of shahid bahonar university was conducted to study the impact of 0, 2.5 and 5µm of mj applied as seed soaking, foliar spray at 6-7 leaf stages, after fruit set and in combination with treatments on growth and fruit yield of ‘semsuri’ melon. to promote growth and fruit yield, two times application of mj is required. mj reduced leaf ion leakage and increased chlorophyll index, relative water content, flesh thickness, plant fresh weight and fruit yield. moreover, mj significantly reduced fruit set that reduces fruit hand thinning. most effective level of mj was 5 µm applied at 3 stages. compared with control, 5µm mj reduced leaf ion leakage (42 percent), and increased chlorophyll index (45 percent), relative water content (32 percent), flesh thickness (33 percent), plant fresh weight (38 percent), root fresh weight (40 percent) and fruit yield (24 percent with two melons per plant and 19 percent with three fruits per plant).