SELECTION FOR DROUGHT TOLERANCE IN DIFFERENT BOTANICAL VARIETIES FROM CUCUMIS MELO L

Abstract

Drought stress is one of the most serious environmental limitations affecting the growth and productivity of vegetable plants. However, tolerant genotypes improve their physiological mechanisms to cope with this stress. The objective of the current study was to determine the effects of water stress on fifteen melon recombinant inbred lines (RILs) (5 RILs galia type and 3 RILs charentais type follow Cucumis melo var. cantaloupensis, 5 RILs ananas type follow Cucumis melo var. ananas and 2 RILs Egyptian melon type follow Cucumis melo var. egyptiacus). Two irrigation levels (full irrigation and 50% of full irrigation) were imposed after completing the formation of the first three true leaves to determine potential drought tolerance of these RILs during 2017 and 2018 early summer seasons at Kaha Vegetable Research Farm (KVRF), Kalubia Governorate. Leaf area, flowering, yield and its components, fruits number/plant and fruit quality were measured for each RIL under both of full irrigation and drought stress conditions. The RILs were classified as drought tolerant if they had very low reduction or increment rates under drought stress compared to full irrigation condition and vice versa. The experimental results showed that both of the RILs 3G (galia type) and 7Ch (charentais type) had a very low reduction or increment rates under drought stress compared to full irrigation condition in all measured traits. So, both of these RILs had a high drought tolerance, but the remaining RILs were classified as intolerant for drought stress. Data revealed that the RILs 3G (galia type) and 7Ch (charentais type) could be considered as a source for drought tolerance.