Growth, Yield and Enzyme Activity Response of Watermelon Accessions Exposed to Irrigation Water Deficit

Abstract

ABSTRACTWater deficiency is an environmental factor affecting crop yield especially in arid and semiarid regions. It is necessary to improve water use efficiency in watermelon (Citrullus lanatus Thunb), a high-water requiring crop. The edible accessions, “TN-94-766,” “TN-94-769,” “TN-94–545,” “TN-94-485,” and “Crimson Sweet,” and the wild-type Colocynth were treated with the irrigation regimes of 100%, 80%, 60%, or 40% of soil available water. In all accessions, leaf area and shoot length decreased and root length increased as water availability decreased up to 40% AW. Colocynth had long shoots and roots, and high ascorbate peroxidase activity, and exhibited high resistance to water deficit. Yield of Colocynth exposed to severe water-deficit level was not changed. The edible accession “TN-94-766” was the most tolerant to water deficit having longer roots, more total fruit yield, and higher catalase and guaiacol peroxidase activities at 60% AW.