Evaluation of the selected sweet potato genotypes tolerance to sweet potato weevil (Cylas puncticollis Boheman)

ABSTRACT

Sweet potato weevil (Cylas punticollis Boheman) is a serious pest throughout sub-Saharan Africa. A study to evaluate 51 sweet potato genotypes for their tolerance to the weevil was conducted in a controlled experiment of no-choice arena. Genotype Tainung was the most susceptible to C. puncticollis. Genotypes Obugi and 5 Nyandere were the most tolerant to C. puncticollis. Many of the genotypes that showed a high level of weevil tolerance had the highest numbers of larvae. The genotypes that showed the highest number of larvae were Kenspot 3, Obugi and 1-Ujili. Nine genotypes including Naspot 1, K117, Kenspot 5, 62 Odhiogo, Tainung, Fundukhusia, Alupe or, SPK 031 and Kenspot 1 had the highest percentage (>75%) of external root damage while genotypes Obugi, Mogesi Gikenja and 5 Nyandere had the least percentage (≤25%). There were positive correlations between root starch and emerged C. puncticollis (r = 0.46341; p ≤ 0.001), root sucrose and emerged C. puncticollis (r = 0.48424; p ≤ 0.001). However, strong negative correlations existed between dry matter and emerged C. puncticollis (r = −0.70881; p ≤ 0.001). The genotypes with a high level of weevil tolerance can be recommended for breeding programmes as parents in relation to weevil tolerance.

KEYWORDS:

• Sweet potato germplasm
• Cylas spp
• sweet potato weevil tolerance

Disclosure statement

No potential conflict of interest was reported by the author.