Comportamento vegetativo, fisiológico e produtivo na cultura do meloeiro sob salinidade.

Abstract

The cultivation of the melon exerts social and economic importance to the Northeast Region for increasing profitability of producers. Abiotic stresses are responsible for the loss of agricultural production worldwide, especially in semi-arid regions, where salinity of water and soil affects the development and production of horticultural species, so the selection of salinity-tolerant melon cultivars is relevant for the exploitation of culture. In this sense, the study aimed to study the influence of salinity of water and soil on the physiological mechanisms involved with growth, photosynthetic efficiency and production of melon cultivars. The experiment was carried out in two greenhouse experiments at the Federal University of Campina Grande, Agro-Food Science and Technology Center, Pombal-PB. In the first trial, a selection of cultivars tolerant to saline stress was carried out, six cultivars of melon were tested during the production of seedlings, with a randomized block design in a 6x5 factorial scheme, six cultivars (Natal, Solares, Goldex, Mandacaru, Iracema and ) And five saline concentrations in irrigation water (0.3, 1.1, 1.9, 2.7, 3.5 dS m -1 EC) with four replications. Biometric, physiological and phytomass measurements were measured. The increase in salinity inhibited the phenological development, photosynthetic apparatus and accumulation of dry mass of the melon seedlings. The cultivars Natal, Iracema and Goldex were the most adapted, while Mandacaru, Solares and Amarelo Ouro the most sensitive to salt conditions in the production of seedlings. The second experiment was carried out with a 3x5 factorial design, three cultivars (Iracema, Goldex and Natal) and five saline concentrations in the soil (0.3, 1.3, 2.3, 3.3, 4,3 dS m-1 EC), in four replicates for evaluation of biometry, physiology and production. The experiment was conducted in 20 L pots under tutorship. The salinity levels of the soil saturation stratum were obtained from the dissolution of sodium chloride (NaCl), calculated according to the treatments, considering the initial salinity of the soil (0.3 dS m- ), the soil weight (20 kg) and the saturation percentage (23%). In the conditions under which the work was carried out, it was concluded t at the increase in the salinity of the irrigation water inhibited the development with physiological damages of the melon cultivars, but, among the cultivars at Natal, it showed higher tolerance to the salts and exceeded the others in productivity.