Tolerância ao estresse salino de clones de cajueiro na fase de mudas.

Abstract

Tolerance to saline stress of cashew tree clones in the seedling stage. The use of inferior quality water in agriculture appears as an alternative for agricultural exploration, however, the salinity of the water used in the irrigation could affect the crops, and it is necessary to develop strategies that provide the tolerance of the plants to the saline stress. Thus, to evaluate the tolerance of precocious dwarf cashew clones to saline stress in the rootstock formation phase. The research was developed under the condition of a protected environment (greenhouse) of the Center of Science and Technology Agrifood of the Federal University of Campina Grande (CCTA / UFCG), Pombal - PB. The treatments consisted of five different levels of electrical conductivity of the irrigation water - Ecw (0.3, 1.0, 1.7, 2.4 and 3, 1 dS m-1), associated with four cashew clones (CCP 76, Embrapa 51, Faga 11 and Crioulo), with three replicates and two plants per plot, the plants being produced in bags with a capacity of 1250 mL. Increased salinity of irrigation water negatively affected the production of cashew rootstocks. Among the cashew rootstocks evaluated, Crioulo presented the best results in growth, total net photosynthesis, dry matter accumulation. Because they have a diameter between 4 and 5 mm, all cashew clones are capable of grafting at 65 days after sowing. Dry leaf phytomass allocation and leaf air ratio were increased by salt addition in irrigation water. The Crioulo cashew rootstock is larger at 65 days after sowing. The shoot dry matter production index and leaf mass ratio increase by increasing the electrical conductivity of the irrigation water. The clones Embrapa 51 and Faga 11 presented the best results for the studied variables (shoot dry matter production index, leaf sclerophilia index, relative leaf area growth rate and stem diameter) at 65 days after sowing.