Abstract

Over the last decade, there has been a gradual growth in cowpea production in Burkina Faso due to its significant income generation for farmers, processors, and traders. However, despite the increasing interest in cultivating this crop, yields are still low due to various constraints, including drought. During drought periods cowpea productivity and growth are significantly reduced. This study was conducted to evaluate the response of seventy cowpea genotypes to water stress, aiming to identify tolerant genotypes with higher productivity in order to contribute to a breeding program to improve cowpea yield in Burkina Faso. The yield parameters of 70 genotypes from the germplasm of the national plant genetics and biotechnology laboratory were evaluated in a split-plot design with three replications in two water regimes which were applied from day 30 after sowing which are well-watered and water-stressed (a three-week interruption of water supply). Several stress tolerance indices were then calculated. The results showed that the applied water stress had a significant effect, resulting in an average reduction of 52.59% in total grain weight. Based on drought indices a hierarchical ascending classification helped to categorize the genotypes into four groups each with a different level of yield and tolerance to water deficit.

Key words: Cowpea, yield, water stress, drought index, tolerance.

Abbreviation

ANOVA, Analysis of variance; CV, coefficient of variance; GDP, gross domestic product; GMP, geometric mean productivity; IPCC, Intergovernmental Panel on Climate Change; LSD, low significant difference; KVx, vigna crossbreeding from Kamboinsé; MP, mean productivity; PCA, principal component analysis; RH0, water regime without stress; RH1, regime with water stress; SSI, stress susceptibility index; STI, stress tolerance index; TOL, tolerance index; YI, yield index; Yp,  yield without stress; Ys, yield with stress; YSI, yield stability index.