Adaptations of cowpea varieties (Vigna unguiculata (L.) Walp.) to the environmental variability in Benin

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The study was realized in the context of farmer management of genotype by environment interaction. The objective was to determine the agronomic and morphological characteristics commonly used by farmers to assess farmer named cowpea varieties through a joint farmer researcher characterization. The trial design was a completely randomized block with 70 varieties as treatments, replicated four times. Data were analyzed using Shannon-Weaver diversity Index and the Analysis of Variance. These varieties varied in growth habit, in colours of leaves, stems, flowers, pods and seeds, and in seed shape and texture. The Shannon-Weaver diversity index revealed a high global mean of morphological diversity among the varieties (H’=1.23), ranging from 1.02 for pod pigmentation to 1.61 for seed coat colour. Within regions, this index varied from 0.33 to 1.57, depending on considered characteristic. Farmers used the photoperiodic response of the late varieties to distinguish early-maturing from late-maturing varieties. In a 3-year experiment, the variety by environment interactions, as expressed by variety-specific effects of planting date, season, and year on yield and yield components, were highly significant. The late-maturing varieties have shown longer reproductive period and more pods and seeds per plant, and higher yield than the early ones.

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Diversity , Vigna unguiculata , photoperiodism , varieties , genotype by environment interaction , yield , Benin

Agronomie Africaine

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Agronomie Africaine