Phenotypic diversity of Moroccan cowpea landraces: insights for crop conservation and food security

Abstract

Cowpea (Vigna unguiculata L. Walp.) is a multifunctional species originating from Africa, where it plays a key role in food security and sustainable agriculture. In Morocco, it remains a marginal crop that has been scientifically overlooked, despite its crucial role in food security, which limits its integration into genetic improvement programs and compromises the sustainable conservation and valorisation of this plant genetic heritage. A field experiment was conducted during the 2023 cropping season using a randomized complete block design with three replications to evaluate the agro-morphological diversity of 19 cowpea landraces collected from different regions of Morocco. A total of 50 qualitative and quantitative traits (morphological, phenological, and agronomic) were assessed at different growth stages. The results revealed a considerable level of variation across most assessed traits, supported by a high total phenotypic diversity (HT = 0.53) and a mean within-population diversity (Hs̄ = 0.45±0.20) that exceeded the among-population phenotypic diversity (GST = 0.16). The average phenotypic diversity (Hp̄) across landraces was 0.45, with no significant differences among landraces. principal component analysis (PCA) revealed significant variation among the 19 cowpea landraces, enabling their grouping based on similarities independently of their geographical origin, with landraces BH3, CF2, HG and TK1 being distinguished by a combination of desirable traits. These results show a considerable level of intra- and inter-landrace diversity among Moroccan cowpea landraces, providing essential information for their conservation, sustainable use, and incorporation into breeding and selection programs, which is particularly relevant as a strategic crop in the current context of climate change.