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ARS Home » Southeast Area » Griffin, Georgia » Plant Genetic Resources Conservation Unit » Research » Research Project #428319

Research Project: Evaluation of the U.S. Plant Introduction Germplasm Collection of Watermelon for Resistance to Anthracnose Race 2

Location: Plant Genetic Resources Conservation Unit

Project Number: 6046-21000-012-07-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jul 2, 2018
End Date: Jul 1, 2019

Objective:
The objectives of this study are to screen all available watermelon accessions and cultivars for resistance to anthracnose race 2 and use the resistant lines to breed cultivars with resistance to both the races in case combined resistance to both races is absent or low.

Approach:
The project will start in spring 2018 with developing screening methods for watermelon seedling assays at North Carolina State University greenhouses and Phytotron. The watermelon germplasm will be screened for resistance to race 2 using 2-4 week-old seedlings. The seedling assay will help identify PIs having resistance to race 2 as well as those having resistance to both races. The seedlings will be rated for resistance on scale of 0-9 similar to the study of Wasilwa et al. (1993). Ratings will be made based on total leaf damage and plant stunting. Accessions with a resistant reaction will be verified and can be used by industry to develop resistant cultivars. The seedling assay will be a randomized incomplete block using 24 cell trays, with each tray having one set of susceptible ‘New Hampshire Midget’ and resistant PI 189225. The incomplete block design will help adjust for the space limitations of the greenhouse and Phytotron. Each replication will have 3 plants per accession and at least 2 replications will be run. The spore concentration will be fine tuned using the methods test. The research schedule will be as follows: 2018 - Develop seedling assay screening methods for resistance to anthracnose; screen all available watermelon PI collection reps for anthracnose, develop sub-lines of the most resistant accessions. Submit data obtained from these studies to the CCGC for the GRIN database (GRIN, 2013) after all replications have been run, and resistance is verified. Data will be formatted in a 9 point system that fits the GRIN disease descriptor. A manuscript reporting findings will be submitted for publication in a scientific journal.