The effect of different levels of irrigation on growth, yield, fruit quality and water use efficiency of grafted and ungrafted melon (Cucumis melo l. Zarde Jalali) under drip irrigation system

In this study, a landrace melon Zarde Jalali as the scion and commercial varieties of Cucurbita rootstocks cv., Shintozwa and Ferro-RZ was used as the rootstock. Grafted plants upon commercial varieties of Cucurbita with own-rooted and ungrafted at three irrigation levels of 60, 80 and 100% (respectively 4984.32, 6124.82 and 7239.41 m3ha-1) based on total available water depletion with drip irrigation system were evaluated. The results showed that with increasing water stress fruit flesh firmness, leaf relative water content and leaf chlorophyll content decreased. Comparison of means showed that maximum (40.76 tonha-1) and minimum (31.16 tonha-1) total yield, obtained by Shintozwa rootstock and self grafted, respectively. The relative changes of performance grafting on increase total yield in Shintozwa and Ferro-RZ rootstocks in compared to non-grafted plants was 23.07 and 14.19 in water deficit conditions respectively. Also the increase in yield was due to the increase in fruit weight so that the average weight of the fruit at Shintozwa rootstock (3.51 kg) and Ferro-RZ rootstock (3.59 kg), was higher in grafted plants compared to non-grafted plants (2.97 kg). Between water levels of 80% and control, no significant differences were found in terms of yield and average fruit weight. Also maximum of marketable yield (38.18 tonha-1) and the lowest yield (26.22 tonha-1) were related to irrigation levels of 100 and 60%, respectively. The maximum (6/7kg m3) and minimum water use efficiency (5/05 kg m3), were related to Shintozwa rootstock and self grafted plants, respectively.