Rootstock effects on alkali stressed melon plants

Abstract

The aim of the present study was to determine alkalinity tolerance of gourd rootstocks grafted with melon and to examine physiological and morphological response of the grafted plants under different pH levels. The climate chamber experiment was carried out to determine main stem length, leaf chlorophyll content (SPAD), branching number, shoot and root fresh mass, as well as root length. Under climate chamber conditions, two melon cultivars [Galia type (Çıtırex F1) and Kırkağaç Manisa Altınbaş type (PI-169303 open pollinated)] were grafted onto two different commercial Cucurbita maxima × C. moschata hybrid rootstocks (Kardosa and Nun 9075) and grown in 8L pots filled continuously with aerated nutrient solution under two different pH levels (7 and 9) with three replications. The results indicated that grafted and ungrafted plants were significantly (P < 0.001) affected by pH levels regarding leaf chlorophyll content (SPAD), branching number, shoot and root fresh mass, as well as root length, whereas there were no significant differences observed regarding main stem length. Grafted plants had better growth performance than ungrafted plants under both control and high pH conditions. Shoot fresh mass of the ungrafted and grafted plants significantly decreased as pH level increased, whereas root fresh mass of the ungrafted and grafted plants significantly increased under high pH level. Branching number was significantly (P < 0.001) affected by grafting combinations and pH levels. Leaf chlorophyll content (SPAD) of the ungrafted and grafted plants significantly decreased as pH level increased, whereas branching number of the grafted plants significantly increased under high pH level. These results suggested that use of interspecific Cucurbita hybrid rootstocks could improve crop performance in melon plants under alkaline conditions.