SALINE STRESS AND EXOGENOUS APPLICATION OF PROLINE IN CASHEW ROOTSTCK

Abstract

The scarcity of good quality water and the occurrence of long dry periods are limiting factors for irrigated agriculture, especially in semiarid regions, which induces the use of saline water and technologies that enable its use in agriculture. In this context, the objective of the present study was to evaluate the influence of exogenous application of proline on growth and phytomass of BRS 226 Planalto precocious dwarf cashew rootstock irrigated with water of different levels of salinity. The study was performed in a greenhouse, in the municipality of Pombal - PB, in a protected environment, using a randomized block design in a 5 x 4 factorial scheme. The treatments consisted of different levels of electrical conductivities of irrigation water – ECw (0.3; 1.0; 1.7; 2.4 and 3.1 dS m-1) associated with foliar application of proline - P (0, 4, 8 and 12 mM), with three repetitions and two plants per plot. The irrigation with saline water of up to 0.85 dS m-1 can be used for the production of BRS 266 cashew rootstck. Proline concentration of 8 mM promoted largest dry phytomass of the BRS 226 Planalto cashew rootstock. The increase in proline concentration up to 12 mM applied via leaf does not attenuate the deleterious effects of salinity on the absolute growth rate of plant height and on the fresh and dry leaf phytomass of the BRS 226 Planalto cashew rootstock.