Evaluation of sweet potato clones for resistance to Cylas puncticollis boheman (Coleoptera: Apionidae ) in Sierra Leone

摘要

A study to evaluate fifteen clones of sweet potato for their resistance to the weevil Cylas puncticollis was under taken over two cropping seasons. The clones were mostly advanced breeding lines or materials released to farmers in Sierra Leone. Numbers of weevils recovered from the different clones and damage levels were significantly different. However, there was a lack of correlation between damage levels and insect counts, despite significant differences for these two sets of criteria among theclones. This suggests that suitability for infestation by the weevil may be different from susceptibility to damage. Clones that suffered least damages had white fleshed tubers and skins which were elongated and dispersed in formation. Other characters for the least damaged clones include deep tuber placement and higher dry matter contents. The clones were however categorised into four groups with varying levels of susceptibility/resistance. The tuber characters are identified as conferring resistance to weevil attack and the most resistant clones are recommended for utilization in breeding programmes as indices or parents or directly as planting materials in farmers fields.