Influence of seeding density on agronomic parameters of cowpea (Vigna unguiculata L.) accession grown in Daloa, west center of Côte d’Ivoire

Cowpea (Vigna unguiculata L.) is most important food legume in tropical regions of Africa. In Côte d'Ivoire, its cultivation is neglected and is carried out on small surfaces with a strong concentration in North of the country. The objective of this study was to determine, in addition to the sowing density, the ideal number of plants per sowing hole for a better cowpea production. Experimental design used was a completely randomized Fisher block with three replications and six treatments per block. The tested spacings with the number of plants per sowing hole are : 20 cm x 20 cm x 01 plant per sowing hole, 20 cm x 20 cm x 02 plants per sowing hole; 30 cm x 30 cm x 01 plant per sowing hole, 30 cm x 30 cm x 02 plants per sowing hole; 40 cm x 40 cm x 01 plant per sowing hole, 40 cm x 40 cm x 02 plants per sowing hole. Observations were made on nine agronomic parameters (plant height, number of leaves, number of branches, span, fresh biomass, number of pods, fresh weight of pods, dry weight of pods and grain weight. Results show that seeding densities and number of plants per sowing hole significantly influence the agronomic parameters. Thus, the lowest sowing densities (62500 plants/ha) corresponding to 40cm x 40cm spacing with one plant per sowing hole gave the best yields while the highest densities (250000 plants/ha) corresponding to 20cm x 20cm spacing with two plants per sowing hole gave the lowest yields for all agronomic parameters.