INHERITANCE OF RESISTANCE TO STRIGA-GESNERIOIDES BIOTYPES FROM MALI AND NIGER IN COWPEA (VIGNA-UNGUICULATA (L) WALP)

Pot and laboratory experiments were performed in order to elucidate th e genetics of resistance of three cowpea (Vigna unguiculata (L.) Walp. ) resistant sources to two biotypes of the parasitic weed Striga gesne rioides (Willd.) Vatke (witchweed). B301, Suvita-2 and IT82D-849 were crossed to susceptible cultivars. Roots of each plant of parental, F-1 , F-2, BC1 and BC2 populations were washed free of soil and examined c losely for S. gesnerioides attachment. Data on resistant and susceptib le 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. gesne rioides biotypes in B301. Suvita-2, which is susceptible to the biotyp e from Maradi, Niger, showed segregation patterns that indicate monoge nic dominant inheritance of resistance to S. gesnerioides biotype from Cinzana, Mall. Results also indicate monogenic dominant inheritance o f resistance to S. gesnerioides biotype from Cinzana in IT82D-849. How ever, the inheritance of resistance to the biotype from Maradi would b e monogenic and recessive in this line. These results suggest that the resistance of all three sources would be easy to transfer to promisin g breeding lines.