Effect of Fruit site on the Stalk upon Yield and Fruit Quality in two Iranian Melon Cultivars under Normal vs. Water Stress Conditions

The following study was conducted at the Research Station of Horticultural Sciences (University of Tehran، Karaj) to investigate the effect of different irrigation levels and fruit site on the stalk upon the traits of: sink-source relationship، yield، and fruit quality in two Iranian melon cultivars. The statistical design was a split split-plot of three replications. Treatments consisted of a factorial arrangement of three irrigation levels (starting irrigation at -50، -65 and -75 cbar)، four thinning levels (retainment of fruit at the second، fourth or seventh node of each of two secondary stems vs. control plants undergoing no thinning) along with two cultivars of Iranian melons (Zard Jalali and Suski Sabz). Results revealed that water stress reduced fruit weight as well as yield. The lowest fruit weight and yield were obtained in the case of severe stress treatment (-75 cb). Thinning methods exerted significant effects on mean fruit weight and yield. The highest values having been obtained from fruits kept on the 7th node treatments. The cultivar “Zare Jalali” bore higher fruit dry matter (%) and benefited from a higher flesh firmness as compared with “Suski Sabz”. The first water stress treatment increased Total Soluble Solids (TSS) content. Retainment of fruits on the 7th node resulted in the highest level of TSS (10. 77%). Water stress resulted in a significant shortening of the ripening time for about 7 days. Retainment of fruit on the 2th node caused earlier ripening of the fruit. Water stress reduced photoassimilate production and improved fruit sweetness. Also، water stress and thinning affected fruit ripening.