Project Number: 8042-21000-274-00
Start Date: Jun 21, 2013
End Date: Jun 20, 2018
Next generation sequencing technology will be used for map-based cloning of anthracnose resistance loci from a recombinant, inbred line tomato population that ARS has developed. To bolster identification of candidate genes for anthracnose resistance, a proteomic survey will also be conducted using resistant and susceptible tomato lines. Markers developed from tomato will henceforth be utilized to identify resistance homologues in the pepper species C. baccatum. Resistance loci will be transferred to C. annuum using bridge lines that ARS has developed. Different Colletotrichum species have been identified as the causative organism responsible for recent outbreaks of green pepper anthracnose fruit rot in Ontario and Midwestern, Southeastern and Mid-Atlantic production areas in the U.S. Isolate species identity and relatedness from these regions will be characterized to ascertain if these isolates share a common lineage. Initial screening surveys for GRSV resistance will focus on C. chinense, the species where resistance to the Tospoviruses TSWV and CaCV has been previously identified. Reported Tospovirus resistance and accession passport data will be assessed and a subset of the available C. chinense accessions will be selected to maximize coverage of the species’ native distribution range. C. annuum land races and accessions representative of the distribution range of C. frutescens, C. chacoense and C. baccatum will be evaluated in a similar manner. Accessions that exhibit high levels of resistance will be crossed to susceptible genotypes to characterize the inheritance of resistance. Initial screening for PSTVd will focus on core collections established for wild relatives of the cultivated tomato. Core collections to be screened will include S. chilense, S. habrochaites, S. pennellii, S peruvianum, and S. pimpinellifolium. Initial screening will focus on a PSTVd variant isolated from an outbreak in tomato and a second variant isolated from potato with confirmed infectivity on tomato. Infectivity will be quantified using real-time PCR. Ongoing development of ornamental and dual-purpose ornamental/culinary pepper germplasm is carried out via breeding strategies that include backcross breeding for simple traits and pedigree and inbred backcross breeding for complex traits. Improved germplasm is evaluated in cooperation with collaborators and released by ARS. Initial germplasm screening for fresh-cut pepper will focus on accessions that bear fruit with thick pericarp. Using knowledge of market types and available passport data, C. annuum accessions will be selected from commercial sources and the USDA, ARS, Plant Genetic Resources Conservation Unit. Accessions with varied fresh-cut quality attributes will be selected to assess applicability of hyperspectral imaging for high throughput phenotyping of fresh-cut quality. Accessions with divergent fresh-cut quality will be intercrossed in a diallel mating scheme to evaluate combining ability for fresh-cut attributes. Superior accessions will be hybridized with sweet and hot pepper breeding lines and BC2 generation hybrids advanced for phenotyping and public release.