Seedling stage drought screening of candidate cowpea (Vigna unguiculata (L) Walp.) genotypes

Abstract

Prolonged drought of cowpea at the seedling stage can affect survival and productivity. This study sought to evaluate cowpea genotypes for their resistance to seedling-stage drought stress. Fifteen cowpea genotypes were used in this study. The experiment was a factorial experiment arranged in a Completely Randomized Design with three replications. Drought stress was imposed for 4 weeks after the full expansion of the first trifoliate leaf. Soil Plant Analysis Development (SPAD) chlorophyll meter readings of unifoliate, first, and second trifoliate leaves of each genotype were measured on a weekly basis due to the predictive ability of chlorophyll content on drought tolerance. The data were subjected to ANOVA, and the means were separated at a 5% probability level. Genotypes were ranked according to their tolerance level based on their chlorophyll inflectance index (CII). The results revealed significant genotype by stress interaction effects. Seedling stage screening under water-stressed conditions in combination with measurements of leaf chlorophyll measurements proved to be an effective way for rapid screening of genotypes for drought tolerance. IT14K-1424-12, IT10K-837-1 and IT10K-303-1 had consistently high chlorophyll content under drought stress for unifoliate and trifoliate leaves. These genotypes also fell into one cluster. Based on CII with a threshold of 51% for the fourth week of drought stress of unifoliate and trifoliate leaves, three genotypes (IT14K-1424-12, IT10K-837-1 and IT10K-303-1) were found to have Type I drought-tolerant mechanism. These genotypes could be used in future breeding interventions or released as varieties.

Keywords:

• Cowpea
• unifoliate leaves
• trifoliate leaves
• water stressed
• chlorophyll
• chlorophyll inflectance index
• drought tolerance

Acknowledgments

This work was supported, in part, by the Bill & Melinda Gates Foundation [OPP1198373] through IITA and ICRISAT on the project “Accelerated Varietal Improvement and Seed Delivery of Legumes and Cereals in Africa (AVISA).” The CSIR-Savanna Agricultural Research Institute (SARI) and the Department of Crop Science of the University for Development Studies are duly acknowledged for the partnership to ensure successful implementation of this work.

Authors’ contributions

Theophilus Kwabla Tengey: Conceptualization; Investigation; Supervision; Methodology; Data curation; Formal analysis; Writing – original draft. Raphael Adu Gyamfi and Edward Kofi Sallah: Supervision; Writing – review & editing. Issahaku Memunatu, Mariam Seidu and Abbas Francis Senyabor: Methodology. Dominic Ngagmayan Ndela, Emmanuel Israel Affram and Charles Naapoal: Analysis; Writing – review & editing. Ophelia Asirifi Amoako: Writing – review & editing. All authors contributed to manuscript revision, read, and approved the submitted version.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the Bill and Melinda Gates Foundation [OPP1198373]

Notes on contributors

Theophilus Kwabla Tengey

Theophilus Tengey is a Research Scientist (Plant Breeder) at the CSIR-Savanna Agricultural Research Institute (SARI) and leads the cowpea Improvement Programme of the Institute.

Raphael Adu Gyamfi

Dr. Raphael Adu-Gyamfi is an Associate Professor of Plant Science at the University for Development Studies (UDS), Nyankpala.

Edward Kofi Sallah

Mr. Edward Kofi Sallah is a lecturer (Plant Pathology) at the UDS.

Memunatu Issahaku

Issahaku Memunatu is a Technical Officer at the CSIR-SARI.

Dominic Ngagmayan Ndela

Dominic Ngagmayan Ndela holds an MPHIL degree in Crop Science from UDS.

Mariam Seidu

Mariam Seidu is a Technical Officer at the CSIR-SARI.

Abbas Francis Senyabor

Abbas Senyabor is a Technical officer with the CSIR-SARI.

Emmanuel Israel Affram

Emmanuel Israel Affram is Graduate Research Associate with the CSIR–SARI.

Ophelia Asirifi Amoako

Ophelia Asirifi Amoako is a Research Scientist at the CSIR-SARI with specialty in cropping systems.

Charles Naapoal

Charles Naapoal is a Research Assistant at the CSIR-SARI.