Crescimento, produção e nodulação de genótipos de feijão-caupi irrigados com água salina.

Abstract

The cowpea is an excellent source of protein and provides the essential amino acids, carbohydrates, vitamins and minerals. It features short cycle, low water requirement can be grown in the semiarid region. This region is the common occurrence of problems with lack of water, which hampers the cultivation of beans. An alternative is the use of irrigation, on the other hand, the misuse of the technology associated with the nature of the soil has promoted the increase of soil salinity problems in the Northeast. The objective of this study was to evaluate the tolerance of 10 genotypes of cowpea to salt stress in the irrigation water. The work was installed in a 10 x 4 factorial design with four replications, whose first factor was the genotypes of cowpea and second four levels of salinity in the irrigation water, treatments were arranged in a completely randomized design. The seeds of all genotypes were provided by Embrapa Meio Norte. The characteristics evaluated were: Number of leaves, plant height, leaf area, shoot dry mass, number of pods, number of seeds, weight of 100 seeds, seeds dry weight, root dry mass and number of nodes. Data were submitted to analysis of variance by F test when significant averages corresponding to genotypes were compared by Tukey test at 5% probability and those related to the salinity levels were polynomial regression analysis. The increasing salinity of irrigation water significantly reduced growth, biomass formation, root development and the number of nodules in all cowpea genotypes, but genotypes 2 (MNC 02 676F-1) and 10 (BRS ITAIM) showed signs of salinity tolerance, with plant height and leaf area and larger than the others.