2019 ASHS Annual Conference

Soil salinity has been one of the most important factors affecting agricultural production worldwide. NaCl has been showed to be one the most common sources of soil salinity. Effects of salinity on cowpea production have been previously reported. Previous investigations have also demonstrated that high soil Na+ could inhibit the uptake of other essential elements that are required for cowpea plant growth and development. In soybean, Cl- was reported to be a good indicator of salt tolerance. However, the evaluation of Na+ and Cl- using standard techniques could be expensive when a large number of genotypes is to be screened for those ions under salt stress. Therefore, this study will aim to identify Na+ and Cl- in cowpea plants subjected to salt stress at seedling stress using micro ion electrodes. A total of 30 cowpea genotypes selected from a panel consisting of 331 accessions evaluated for salt stress under greenhouse conditions will be used. Of the 30 genotypes, 15 were the most tolerant and 15 were the most susceptible to salt stress among the 331 cowpea panel. Each genotype is replicated six times. In Vivo measurement will be achieved by introducing the electrodes into cowpea leaves and stems. This will help evaluate leaf and stem Na +/ Cl- contents and investigate the flow of salt ions within cowpea plant shoot during salt treatment. In Vitro measurement of leaf Na+/ Cl- using micro ion electrodes will be achieved using a previously described protocol. Data will be collected at one week after salt treatment and at the time when the susceptible control is completely dead, respetively. Data will be analyzed using SAS v. 9.4. We expect a significant discrepancy between the two groups (tolerant and susceptible) based on Na+ and Cl- contents by using micro ion electrode. This study will enhance salt tolerance phenotyping strategy in cowpea and will be completed by an epigenetic study.