Yields and forage nutritive quality of high-yielding dual purpose cowpea (Vigna unguiculata L. Walp.) varieties in the Sahelian low-input cropping system

摘要

Cowpea is a major food legume crop in the Sahel with tolerance to drought and to the nutrients-leached acid sandy soils of this region. However, the existing cowpea varieties grown by farmers are low yielding and pest sensitive which make them unsuitable to satisfy farmer’s needs. The objective of this study was to identify high-yielding cowpea varieties which are well adapted to the Sahelian ecosystem. Eight dual-purpose cowpea varieties from various sources were tested with and without insects control in Niger during two cropping seasons (2005 and 2007). In 2005, a relatively wet year, KVX 745-11-P and four other varieties (ISV 20, ISV 40, ISV 128 and IT98D-1399) gave highest grain yields ranging from 1220 to 1521 kg ha-1. In the dry year (2007), the highest grain yield was recorded with ISV 128. There were also significant differences in forage yield between varieties in both the wet and dry year. Application of insecticide increased cowpea grain yields significantly. Cowpea produced without insect control (spray) resulted in high grain yields losses and increased cowpea fodder yields in both years. KVX 745-11-P was the most sensitive variety to insects whereas IT98D 1399 seemed to be relatively the most insect tolerant variety. There were no significant differences between varieties in most forage quality parameters. These results provide the possibility of a potential extension of dual-cowpea varieties for improved food security in the Sahel.Keywords: Dual purpose cowpea, grain yield, fodder quality, sahel.