Sweetpotato Whitefly (Bemisia tabaci) Resistance and Trichome Characterization in Capsicum galapagoense and Capsicum pubescens

Abstract

The sweetpotato whitefly (also known as the silverleaf whitefly and cotton whitefly), Bemisia tabaci Genn., a major pest of pepper ( Capsicum annuum L.) is found throughout the tropics and subtropics. The exploitation of wild relatives of pepper as sources of pest resistance may be a successful strategy for the development of improved and resistant cultivars, reducing the need for chemical applications. Limited wild Capsicum species have been evaluated for resistance to insect pests, particularly sweetpotato whitefly. The objectives of this study were to evaluate three wild accessions, including Capsicum galapagoense and two accessions from Capsicum pubescens , for resistance to sweetpotato whitefly based on antixenosis (choice bioassay). The density of glandular and nonglandular trichomes were also evaluated. The highest resistance was identified in C. galapagoense accession PBC1892 (NMCA50026). In addition, two accessions of C. pubescens , PBC1894 (US Department of Agriculture PI 235047) and PBC1893 (NMCA80090), were moderately resistant. Type IV trichomes were present only on C. galapagoense and C. pubescens and were positively associated with whitefly resistance. In contrast, type VII trichomes on all three accessions were negatively associated with whitefly resistance. This study provides novel sources of resistance to sweetpotato whitefly that can be used in a prebreeding program to develop insect-resistant pepper cultivars.