Cluj-Napoca Varietal Response of Cowpea (Vigna unguiculata (L.) Walp.) to

The parasitic plant Striga gesnerioides (Willd) Vatke is becoming a serious threat to cowpea production in Sub-Saharan Africa. At least 7 races of S. gesnerioides exhibiting specific virulence have been identified. The objectives of this study were to identify sources of resistance to S. gesnerioides race SG5 spreads in northern Cameroon and to study the inheritance of the resistance. Twelve accessions of cowpea, IT98K-205-8, ‘IT98K-503-1’, ‘IT98K-1092-1’, ‘IT99K-216-1-1’, ‘IT98K-494-6’, ‘IT99K-529-4’, ‘IT99K-573-1-1’, ‘IT99K-573-2-1’, ‘IT00K-1207’, ‘IT03K-378-4’, ‘IT04K-227-4 ’ and ‘VYA ’ were assessed in field trials for resistance to S. gesnerioides race SG5 in Maroua, northern Cameroon and the genetics of the resistance from two sources was elucidated in artificially infested pots. Data on resistant and susceptible cowpea plants were analyzed using the chi-square test to ascertain the goodness of fit to different genetic ratios. Tests of resistance using field screening techniques showed that among these varieties, four were susceptible, four tolerant, two partially resistant while ‘IT99K-573-1-1 ’ and ‘IT98K-205-8 ’ appeared completely resistant to Striga race SG5. On susceptible varieties, the mean number of emerged S. gesnerioides plants 9 weeks after sowing was 1.8 to 2.4 per cowpea plant, while completely resistant lines carried none. The cowpea genotypes showed significant differences for percentage of infected plants, the decimation rates and Striga height. On susceptible genotypes, the seeds yield losses due to Striga infestation varied from 28.4 to 36.6 % while for the fodder yield thes