Thrips-resistant cowpea genotypes for sub-saharan africa

Overview

Flower bud thrips are a major insect pest of cowpea in sub-Saharan Africa, causing yield losses ranging from approximately 20% to 100% depending on growing conditions. Conventional control relies heavily on synthetic insecticides, which carry well-documented health and environmental risks. This program addresses the problem through genetic resistance, developing cowpea varieties with innate ability to withstand thrips infestation. By reducing dependence on chemical sprays, the approach supports biodiversity preservation, lowers production costs for smallholder farmers, and contributes to more sustainable cowpea cultivation across the region.

Technical specifications

Breeding approach:

• Conventional hybridization between identified thrips-resistant donor lines and farmer-preferred elite cowpea varieties
• Repeated backcrossing up to the sixth generation to stabilize resistance traits while retaining preferred agronomic characteristics
• Selection under natural thrips infestation pressure in field conditions
• Combined morphological and molecular marker-assisted selection to track resistance genes during breeding

Genetic resources:

• A panel of 25 cowpea genotypes assembled from seven sub-Saharan countries, including Ghana, Mali, Nigeria, Niger, Burkina Faso, Togo, and South Sudan
• Laduni 1B identified as a resistant line, with approximately 20 additional genotypes showing moderate resistance to thrips
• Preliminary screening conducted using a 5 by 5 alpha lattice field design with two checks

Target outcome:

• Development of stable, uniform cowpea cultivars combining thrips resistance with farmer-accepted traits
• Registration and official release of new varieties, expected within four to five years
• Genetic variability generated through this work intended to support further variety development

Technology readiness level

The program has completed preliminary field screening that identified resistant and moderately resistant genotypes, with results published in Bonney et al., 2019. The current phase focuses on hybridization and backcrossing to introgress resistance genes into elite farmer-preferred varieties. Variety registration and release are projected for the fourth or fifth year of the breeding cycle. The technology is at an advanced breeding stage but has not yet produced commercially released cultivars.