Identification of host plant resistance to silverleaf whitefly in cotton: Implications for breeding

摘要

Silverleaf whitefly (SLW), Bemisia tabaci (Gennadius) B Biotype, is an important pest of cotton in many countries, predominantly due to secretion of sugars causing honeydew contamination on lint. This results in downgrading of quality and subsequent price received by the grower. A two year field and glasshouse study evaluated host plant resistance to SLW on a range of cotton genotypes from both tetraploid (Gossypium hirsutum L, Gossypium barbadense L.) and diploid (Cossypium arboreum L., G. thurberiTod. and Gossypium trilobum (DC.) Skovst) species. The population development of both adult and nymphal stages were compared, together with adult preference and oviposition preference. Sources of resistance to SLW were found in genotypes with okra and/orglabrous leaf traits as well as C. arboreum genotypes that had hairy normal leaves. This study revealed there were three different types of host plant resistance mechanisms against SLW; (1) okra leaf traits which reduced adult preference, (2) glabrous leaf traits which reduced oviposition preference and (3) possible biochemical traits in G. arboreum which reduced immature development and/or survival. Although any potential negative effects of these traits on yield would need to be carefully evaluated,these traits are clear targets for breeding to develop host plant resistant cultivars.