Effects of Salinity Sources on Growth, Physiological Process, Yield, and Fruit Quality of Grafted Rock Melon (Cucumis melo L.)

Abstract

There is an increase in demand for high-quality rock melon for the local market. Supplementing salt with a nutrient solution is a viable approach that can be implemented to improve fruit quality. Therefore, this study aims to determine the best salt treatment that can be utilized to increase fruit quality without reducing growth, yield, and physiological process. The study is conducted by grafting (DAG) rock melon/bottle gourd at 18 days with four sources of salinity: basic nutrient solution (BNS) (2.5 dS m-1), sodium chloride (NaCl) (50 mM) + BNS (7.1 dS m-1), potassium nitrate (KNO3) (50 mM) + BNS (7.1 dS m-1), and high strength nutrient solution (NS) (7.1 dS m-1). The plants were arranged in a randomized complete block design (RCBD) with four replications. Salinity induced using KNO3 + BNS sustained most growth variables, fruit quality, relative water content, and leaf gas exchange compared with control. However, applying NaCl + BNS and high strength NS could sustain all physiological processes and increase fruit quality components, such as total soluble solid and sugar-acid ratio compared to control. Fruit weight had reduced regardless of salinity sources than those grown in control with their respective fruit weight reduction of 28.8%, 28.26%, and 27.72%. To conclude, incorporating NaCl at 50 mM is the most feasible approach to be applied on grafted rock melon/bottle gourd even though the fruit weight had reduced. It is due to the high fruit quality measured, capable of sustaining all physiological processes, provides lower cost, and is easily accessible than other sources of salinity.