Cowpea leaf width correlates with above ground biomass across diverse environments

Authors: DIGRADO, A - Oak Ridge Institute For Science And Education (ORISE); GONZALEZ-ESCOBAR, E - Lancaster University; OWSTON, N - Lancaster University; PAGE, R - Lancaster University; MOHAMMED, S - Ahmadu Bello University; UMAR, M - Ahmadu Bello University; BOUKAR, O - International Institute Of Tropical Agriculture (IITA); Ainsworth, Elizabeth - Lisa; CARMO-SILVA, E - Lancaster University

Submitted to: Legume Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2022
Publication Date: 3/21/2022
Citation: Digrado, A., Gonzalez-Escobar, E., Owston, N., Page, R., Mohammed, S., Umar, M.L., Boukar, O., Ainsworth, E.A., Carmo-Silva, E. 2022. Cowpea leaf width correlates with above ground biomass across diverse environments. Legume Science. https://doi.org/10.1002/leg3.144.
DOI: https://doi.org/10.1002/leg3.144

Interpretive Summary: Cowpea is an important food security crop in Sub-Saharan Africa. The aim of this work was to identify morphological traits that cowpea breeders could easily incorporate into programs for increasing crop biomass and yield. Over 70 diverse lines from a Nigerian collection and an intercross population were tested in the glasshouse and the field. There was a strong correlation between leaf width and total above-ground biomass, which was significant in both the field and the glasshouse and in different populations. This suggests that leaf width could be used to rapidly select cowpea lines for high biomass production.

Technical Abstract: Cowpea (Vigna unguiculata [L.] Walp.) yields within the dry savannahs of Sub-Saharan Africa are low. Given the contribution of cowpea to food security in this region, it is essential that high-yielding varieties are developed to improve crop productivity in a sustainable manner. Identifying morphological or physiological traits that correlate with biomass could assist breeders with rapid screening of diverse germplasm. This study investigated 23 diverse Nigerian cowpea lines in an environmentally controlled greenhouse and 50 diverse lines from a Multiparent Advanced Generation Intercross (MAGIC) population in the field to identify easily measurable traits associated with high above ground biomass. Correlation analyses found that leaf traits were significantly and positively correlated with above ground biomass, and the leaf width of the youngest fully expanded leaf was the best indicator of biomass yield. Analysis of variance identified significant differences among the genotypes for all measured traits, indicating that there is genetic variation among these varieties and opportunity for selection. These results from the greenhouse and the field indicate that the leaf width of the youngest fully expanded leaf can be used to rapidly select cowpea lines with high biomass production potential.