Sources of resistance to sweetpotato weevil (Coleoptera: Apionidae) in sweetpotato vines
1997
Talekar, N.S. (Asian Vegetable Research and Development Center, Taiwan (Republic of China))
Sweetpotato weevil [Cylas formicarius (F)] attacks vines and roots of the sweetpotato [Ipomoea batatas (L.) Lam.] plant in the field. Because of failure to find genetic sources of resistance to the weevil in roots, 1243 sweetpotato clones were screened in three field tests for resistance to this insect in vines. Evaluation of resistance was based on the number of sweetpotato weevils found inside the stems and the number of plants damaged by the insect. Two sweetpotato clones I 123 (B 6712) and I 959 (W-115), and four progenies from crosses between sweetpotato and Ipomoea trifida (HBK) G. Don showed very high levels of resistance to sweetpotato weevil. Resistance clones had practically none or fewer insects and fewer plants with weevil damage compared with the susceptible clones. There was a highly significant positive correlation between the number of weevils in vines or the number of plants damaged and the diameter of the stems used as planting materials.
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