Sustainable Approaches to Enhance Water Productivity in Cucumis melo

Abstract

Drought poses one of the biggest threats to horticultural production by reducing plant growth, photosynthetic efficiency, and yield. Sustainable strategies such as grafting, deficit irrigation, and an improved understanding of plant-water relations offer potential solutions to enhance crop water productivity (CWP). This study conducted at the University of Nevada, Reno, evaluates three sustainable approaches to increase CWP in melons (Cucumis melo L.) under high desert conditions: (1) the effect of melon grafting on yield using squash hybrid rootstocks, (2) determining the physiological transition from water-consumptive to water-conservative (impaired photosynthetic activity) in the water potential curve (predawn and midday water potential relationship) in response to progressive drought stress of grafted and ungrafted melons, and (3) the impact of two-levels of consistent deficit irrigation regimes, moderate (70% of full irrigation ) and severe (50% of full irrigation), on melon's physiology, yield, and CWP. Results showed (1) no significant yield advantage of grafting melons onto squash hybrid rootstocks, with outcomes highly dependent on environmental factors (i.e., location and seasonal weather). (2) A Piecewise linear regression model best conceptualized the water potential curve, effectively predicting the transition from water-consumptive to water-conservative behavior at -0.72 MPa of predawn water potential under field condition. The water potential curve may offer a valuable tool for irrigation scheduling and the breeding of drought tolerant crops. (3) Moderate deficit irrigation maintained yields comparable to full irrigation, while saving approximately 25% of water and increasing CWP. Integrating plant physiological modeling and deficit irrigation could be used to enhance drought resilience and CWP in melons and potentially other horticultural crops.