Initial growth and tolerance of melon cultivars under salt stress

Abstract The melon crop is normally developed in semiarid regions, where water resources are limited. This scarcity of water is a strong stressor on the crops, and requires the supplementation of existing water supplies with poor quality water, especially saline water. This can impede the growth and production of plants; however, the use of tolerant genotypes may minimize this problem. Thus, a greenhouse experiment was developed at the Federal University of Campina Grande - UFCG, Pombal Campus, Paraiba State, Brazil, in order to study the emergence, initial growth, and tolerance of melon cultivars irrigated with waters of different salt content. We studied three melon cultivars (Gaúcho Redondo, Gaúcho Casca de Carvalho and Halles Best Jumbo) irrigated with five levels of saline water (0.6; 1.2; 1.8; 2.4; and 3.0 dS m-1), arranged in a 3 x 5 factorial scheme, with the treatments distributed in a randomized block design with four replications. The plants seeds were monitored for 30 days after sowing, and at 30 days the growth and salinity tolerance index was evaluated. Cultivar Halles Best Jumbo was the most tolerant to saline water during initial stage of growth, while the Gaucho Redondo was more sensitive to salinity. It was found that saline waters up to 1.8 dS m-1 were suitable for irrigation of melon plants round Gaucho and waters up to 2.4 dS m-1 could be used for irrigation of Gaucho Casca de Carvalho and Halles Best Jumbo crops during the initial growth phase.