Response of sweet potato selections to the southern root-knot nematode Meloidogyne incognita in Venezuela.

Twenty-eight Ipomoea batatas selections in the Root and Tuber Germplasm Col lection of the Agronomy Department of Central University of Venezuela, Mara cay, Venezuela, were evaluated for reaction to the southern root-knot nemat ode, Meloidogyne incognita race 2 Initial densities (Pi) of a combination o f 6 eggs and second-stage juveniles per one cm(3) of soil were used in a gr eenhouse replicated study. All selections, except 'UCV-8', were susceptible to M. incognita infection. The nematode reproduction rate (Pf/Pi) on 'UCV- 8' was < 1 and the galling index value, on a scale 0-5, was 2.5. Low reprod uction rates and gall index values of 2.9, 2.4, 2.4, and 2.3 were observed on die selections 'UCV-21', 'UCV-22','North Carolina' and 'E-690' respectiv ely.