Identification of tolerant cowpea genotypes to salinity evaluated by the multivariate method/ Identificacao de genotipos de feijao-caupi tolerantes a salinidade avaliado por meio de metodo multivariado

The objective of this research was to identify genotypes tolerant to stress caused by NaCl and the mixture of NaCl, Ca[Cl.sub.2] and Mg[Cl.sub.2] in irrigation water in the early stages of development. The levels of electrical conductivity of saturation extract were 0, 0.25, 5.0 and 7.5dS [m.sup.-1]. The tolerance of cowpea was evaluated by the relative reduction in shoot dry matter of each genotype. The genotype CE-182 had more tolerant levels of 2.5, 5.0 and 7.5dS [m.sup.-1] in saline water with NaCl. In the solution mixture of salts, the genotypes and CE-9 and CE-551 were the most tolerant. According to the results obtained by clustering using the UPGMA method it can verified that the most promising combinations for crosses which obtained superior progenies in the development of cultivars tolerant to salinity were found between genotypes CE-182 and CE-250 and between CE-551 and CE-9.