Assessment of Tolerance Potential of Cassava (Manihot esculenta Crantz) Genotypes to Whiteflies (Bemisia tabaci) in East Cameroon

Abstract

Cassava is a basic staple in Cameroon whose industrialization faces major constraints especially those related to the management of whiteflies (Bemisia tabaci), a vector of the African cassava mosaic virus (ACMV). This work has as main objective to identify the tolerance of some cassava genotypes to whiteflies and to undertake an agro-morphological characterization of infected cultivars to the ACMV. Data were collected from September to November 2015 on six cultivars: Five improved (TMS92/0057, TMS92/0067, TMS92/0326, TMS96/1414 and TME419) and one local (NTOLO), on a young plot (three months old) and mature plot (six months age). Adult whiteflies were counted on the underside of the last leaves of one apex and for nymphs; they were counted randomly between the ninth and fourteenth leaves. Three cultivars (TMS96/1414; TMS92/0057 and TMS92/0067) ramified early with a large number of apices. For the younger plants (three months old), three cultivars (NTOLO, TMS96/1414 and TMS92/0326) harbored the largest number of adult whiteflies, whereas two others (TMS92/0326 and TME 419) were the most attacked by the ACMD. Younger plants (3 Months old) were most vulnerable to ACMV attack (r = 0,307** with whiteflies population), while the older ones (at 6 Months), represent early senescence period for short-cycle genotypes.