Photochemical efficiency and yield of melon plants cultivated under different irrigation levels

Abstract

The melon crop has great social and economic importance to Northeastern Brazil, however, lack and excess of water affect growth. Therefore it is necessary to determine ideal water amount to obtain the maximum yield. This research work aimed to evaluate photochemical efficiency and yield of Cantaloupe melon under different irrigations levels. The work was carried in field conditions, adopting a randomized block design with 4 treatments [(60, 80, 100, and 120% of ET0 (mm day^-1) corresponded to the volume of water accumulated during the cycle: 1250, 1680, 2110 and 2540 m³ cycle^-1, respectively, and 6 replications with 10 plants per experimental unit. The following variables were analyzed: chlorophyll fluorescence, yield and physical and chemical attributes fruits. The 80% ETo water level provided the higher efficiency of Photosystem II. There was lower production of Class I fruits with the level irrigation higher than 100% ETo; and the incidence of the class II and III fruits increased linearly with increasing water levels. There was a reduction in fruit size with irrigation higher than 100% ETo, however the sugar content was satisfactory with irrigation up to 80% ETo. Water levels based on 100% ETo provide the best physiological indices and increasing in production variables.