STUDIES ON BIOLOGY AND CONTROL OF STRIGA .2. VARIETAL RESPONSE OF COWPEA (VIGNA-UNGUICULATA [L] WALP) TO STRIGA-GESNERIOIDES

Resistant cowpea varieties to Striga gesnerioides were grown on striga sick plots at Maiduguri, Northern Nigeria, in order to check their response to S. gesnerioides in various regions in West Africa. Under field conditions all the varieties including highly resistant varieties were all attacked by Striga at both 9 and 12 weeks after sowing. However, B-301, Sutiva-2, IT82D-479-1 and IT82D-849 varieties had significantly very low Striga infestation compared with KVX 183-1 variety. These varieties also show higher cowpea yield compared with other highly infested varieties. But the pot experiment shows that B-301 variety is highly resistant to S. gesnerioides as no Striga germination was observed. Therefore, it is strongly believed that under field conditions Merrimia emarginata a weed host of S. gesnerioides which was common on the experimental site might have contributed to the presence of S. gesnerioides in some of the highly resistant varieties such as B-301.