Location: Plant Genetic Resources Unit (PGRU)
Project Number: 8060-21000-027-021-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 31, 2023
Cooperator will screen diverse NPGS cucurbit accessions for biotic pathogen resistances and key horticultural quality traits. This project will support development of improved cultivars to increase food accessibility in the US for historically underserved groups, create resistant rootstocks, and as a source of novel resistances that can be transferred to other mainstream cucurbits through genetic engineering approaches.
During the 2023 growing season, all 177 available accessions of L. siceraria will be grown out by the cooperator to observe resistance to powdery mildew (PM) and downy mildew (DM). Accession will be grown under standard cucurbit production conditions. Two replications will be grown at the Freeville research farm location in a randomized block design. This evaluation will be made more robust with the addition of multiple control plots of cultivars with known intermediate resistance for spatial corrections of disease severity (‘Marketmore 97’ for intermediate DM resistance and a squash heterozygous for the incompletely dominant Pm-0 gene for PM). Control plots of susceptible cultivars and PM resistant winter squash, 'Bugle’, and DM resistant cucumber, ’DMR401’, will be used to distinguish resistant vs susceptible accessions. AUDPC (area under the disease progress curve) will be calculated on the plot level for each accession relative to controls. PM will be scored as percent affected area on leaf surfaces and petioles and cucurbit DM with as percent affected canopy. The cooperator will contribute data for inclusion within GRIN-Global. In addition, the cooperator will work with the curator in determining if there are unavailable accessions that can be grown in the disease trials and self-pollinated to increase available seeds back to the collection. The cooperator and the Curator will work on the Crop Vulnerability Statement for “gourds” under the Cucurbit Crop Germplasm Committee. The cooperator proposes to write a Crop Vulnerability statement working with stakeholders in this area.