Screening of cowpea germplasm for resistance to Striga gesnerioides in Niger
The parasitic weed, Striga gesnerioides, is a major constraint to cowpea production in sub-Saharan Africa. It causes significant yield reductions of cowpea, especially in dry areas. The objective of this study was to evaluate the response of 80 genotypes to Striga gesnerioides under natural infestation. The results showed significant variations in the resistance of cowpea lines to Striga; lines IT93K-693-2, IT99K-573-1-1 and IT98K-205-8 being free from Striga infestation; while lines 2491-171, 2472-154 and Suvita-2 supported few Striga shoots. The other lines supported more and varied numbers of emerged Striga shoots. The reduction of yield due to Striga infestation was more pronounced for the susceptible genotypes as compared to the resistant and tolerant lines. The high level of resistance observed in some breeding lines can be exploited in breeding cowpea for resistance to Striga. Principal Component Analysis (PCA) and clustering grouped the genotypes in three main clusters as follow: (i) high yielding and tolerant to Striga (ii) moderate yielding and resistant (iii) low-yielding and susceptible.
Key words: Parasitic weed, Striga resistance