Genotypic and environmental effects in seven cowpea, Vigna ungiculata L. Walp genotypes under natural infestation by Etiella zinckenella treitscke at two Locations in Southern Egypt

egipto egypt etiella zinckenella genetic variation genotipos genotypes génotype heritability héritabilité infestación infestation pest resistance resistencia a las plagas résistance aux organismes nuisibles variación genética variation génétique variedades varieties variété vigna unguiculata égypte