Inheritance of resistance to Striga gesnerioides biotypes from Mali and Niger in cowpea (Vigna unguiculata (L.) Walp.)

Abstract

Pot and laboratory experiments were performed in order to elucidate the genetics of resistance of three cowpea (Vigna unguiculata (L.) Walp.) resistant sources to two biotypes of the parasitic weed Striga gesnerioides (Willd.) Vatke (witchweed). B301, Suvita-2 and IT82D-849 were crossed to susceptible cultivars. Roots of each plant of parental, F₁, F₂, BC₁ and BC₂ populations were washed free of soil and examined closely for S. gesnerioides attachment. Data on resistant and susceptible cowpea plants were analyzed using the chi-square test to ascertain the goodness of fit to different genetic ratios. Segregation patterns indicate monogenic dominant inheritance of resistance to both S. gesnerioides biotypes in B301. Suvita-2, which is susceptible to the biotype from Maradi, Niger, showed segregation patterns that indicate monogenic dominant inheritance of resistance to S. gesnerioides biotype from Cinzana, Mali. Results also indicate monogenic dominant inheritance of resistance to S. gesnerioides biotype from Cinzana in IT82D-849. However, the inheritance of resistance to the biotype from Maradi would be monogenic and recessive in this line. These results suggest that the resistance of all three sources would be easy to transfer to promising breeding lines.