Production, water-use efficiency and post-harvest quality of hydroponic mini watermelon under salinity stress

Irregularity or shortage of rainfall in semi-arid regions forces farmers to use low-quality water to irrigate crops. The present study aimed to assess the water-use efficiency and post-harvest quality of 'Sugar Baby' mini watermelon in response to different electrical conductivities of the nutrient solution [2.5 (control), 3.5, 4.5, 5.5 and 6.5 dS m(-1)], in a floating hydroponic system. The experimental design was completely randomized, with four replicates. The water consumption, production and water-use efficiency were evaluated, as well as qualitative and physico- chemical variables of the fruits. The total water consumption of the plants during the crop cycle varied between 43 (6.5 dS m(-1)) and 54 (2.5 dS m(-1)) L plant(-1) among the treatments, with water-use efficiency of 0.031 kg L-1. The greatest reductions due to the nutrient solution salinity were observed for the rind thickness and fruit mass (8.80 and 5.69 %, respectively, per unit increase in dS m(-1)). The salinity of the nutrient solution did not influence the soluble solids content and fruit maturity index, but it had a negative effect on the pH and titratable acidity.