Okonkwo, J.C. 2002 Evaluation of cassava genotypes for yield and response to biotic stress in Jos Plateau, Nigeria.. Journal of Sustainable Agriculture and the Environment 4(1): 29-35.

Notes: Cassava genotypes TMS 30572, TMS 30555, TMS 40764, TMS 82/0422, NR/85200, NR/8579, NR/8591, NR/85191 and a local variety (Don Riyom) were evaluated for yield and response to some cassava diseases and pests at Kuru, Jos Plateau, Nigeria, in 1996/97 and 1997/98 growing seasons. Fertilizers were applied at 100 kg N, 18 kg P and 20 kg K/ha at 8 weeks after planting. The maximum and minimum air temperatures of the experimental site were low, averaging 23 and 13.2 deg C, respectively. Rainfall records also showed that five months of the year were rain free. The average plant height from first branching was 28.9 cm. Plant growth was retarded and small size tubers were harvested at the end of 12 months. Tuber yield was low, ranging from 4.8-16.1 t/ha. The severity of African cassava mosaic virus infection on cassava plants was higher in the first three months after planting than six months later. Scores for cassava bacterial blight [Xanthomonas axonopodis pv. manihotis] and cassava anthracnose disease [Colletotrichum gloeosporioides f.sp. manihotis] were low, averaging 1.5 and 1.4, respectively, on a scale of 1-5. There was low incidence of mealy bug (Phenacoccus manihoti) and green mites (Mononychellus tanajoa) in the study, implying either absence of the pests or the resistance of the genotypes to the pests. Based on yields and responses of the cassava genotypes to the diseases and pests attacks, TMS 82/0422, TMS 40764, NR/8579 and NR/85200 were promising for production in the Jos Plateau area.