Mapping QTLs for resistance to Bemisia tabaci MEAM1 in melon accession PI 122847

The sweetpotato whitefly (Bemisia tabaci Middle East-Asia Minor 1; MEAM1) is a devastating pest that damages many important food and fiber crops by phloem feeding, production of honeydew, and transmitting viruses. In the United States Southwest, high MEAM1 populations and the presence of several MEAM1-vectored cucurbit viruses severely limit melon (Cucumis melo) production. The problem is so acute that late-season melon plantings in some regions are no longer economically viable. Control of MEAM1 is further complicated by this pests' high potential to develop insecticide resistance.

Host-plant resistance is a sustainable control tactic that has the potential to form the foundation of a successful integrated pest management program for MEAM1. The melon accession PI 122847 has demonstrated field resistance to MEAM1. As the first step towards advancing resistance into commercial melon lines, our goal was to identify quantitative trait loci (QTLs) associated with this resistance trait. We crossed PI 122847 with susceptible melon line ‘Top Mark’ to create an F2-derived-F3 mapping population. Using a no-choice oviposition assay, we then phenotyped 1283 melons plants representing 122 F2 families and the two parent lines. Whole genome sequencing was performed on leaf tissue from each F2 plant and the parent lines to generate high-confidence SNP markers. SNPs and phenotype data were analyzed to search for QTLs for MEAM1 resistance. Results of this analysis will be presented.