Effects of Salinity on Growth and Root Development of Cowpea in Hydroponic System

Abstract

The experiment was conducted in August 2018 at the Tennessee State University (TSU) greenhouse in Nashville, Tennessee, United States of America. Cowpea is a protein-rich leguminous crop and an important source of food for humans and fodder for animals. It has numerous benefits to mankind and is the second most important legume crop in Ghana. However, cowpea production is far below its potential due to various abiotic stress factors. Among the major abiotic factors affecting cowpea production in both tropical and temperate regions is salinity. Although cowpea is cultivated on saline soils, its yield is significantly reduced under such conditions. The adverse effects of salinity can be mitigated through the use of genotypes that are tolerant to high soil salinity. The objective of this study was to screen cowpea genotypes for salt tolerance. The experiment consisted of 2 × 42 and 2 × 93 factorial treatments (salt × genotype) arranged in a randomized complete block design with three (3) replications for both field and greenhouse experiments. Seedlings were established in a hydroponic system and subjected to two treatments, namely, with and without salinity (sodium chloride) stress, using a standard nutrient solution. Cowpea growth parameters were used to assess salt tolerance. All measured parameters showed significant differences (p ≤ 0.05). Salinity stress severely affected yield, resulting in a 39% reduction. Eleven USDA and seventy RIL genotypes survived the salt stress in the growth medium. These genotypes can be utilized in breeding programs to develop salt-tolerant cowpea varieties for farmers.