Effects of humic acid and salicylic acid on yield and fruit quality of the Zard Jalali melon under water deficit stress

The effect of salicylic acid (SA) and humic acid (HA) on yield, fruit quality and water use efficiency of melon "Zard Jalali" accession under water deficit stress condition was evaluated. This experiment was carried out as split plot based on randomized complete block design with three replicates in research filed of university of Zanjan during 2015. Treatments consisted arrangement of 7 foliar application levels [Control, H (25, 50, 75 mg/L) and SA (0.5, 1, 1.5 mM)] and three irrigation levels (starting irrigation at 100, 70 and 40% ETc). The results showed that irrigation had significant effects on yield and fruit quality. The lowest fruit weight (1.956 kg), number of fruits per plant (1.5), plant yield (2.91 kg), fruit firmness (4.67 kg/cm2), chlorophyll content (0.11 mg/100g FW) and the highest fruit flesh percent (%75) and water use efficiency (16.43 kg/ m3) were obtained in water deficit stress 40% ETc. Also, maximum fruit number and fruit yield per plant was obtained using H 75 mg/l and the highest value of fruit flesh (62.13%) was observed in treatment of SA 1.5 mM. The Irrigation × foliar treatments interactions results suggested that highest fruit yield (7.79 kg/plant) and TSS (11.31%) was obtained in SA 1 mM and H 0.25 mg/l, respectively under irrigation 100 ETc%. According to the results, application of HA and SA enhanced, fruit yield and quality under water deficit conditions.