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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Enhancement of Lettuce, Spinach, Melon, and Related Species

Location: Crop Improvement and Protection Research

Project Number: 5305-21220-005-00
Project Type: Appropriated

Start Date: Apr 22, 2013
End Date: Apr 21, 2018

Objective:
The focus of this research program is on quality traits, resistance to diseases, insects and abiotic stresses of lettuce, spinach and melon considered by the respective industries and the scientific community to be the most critical to production. The overall goal is the development of elite germplasm and cultivars with improved quality and productivity, and new knowledge of the genetics and breeding of lettuce, spinach and melon. Objective 1: Identify and select for novel sources of high-level host plant resistance in lettuce to priority diseases, insects, physiological defects and improved phytonutrient content. Improved lettuce germplasm and/or finished varieties will be released and incorporated into the ARS National Plant Germplasm System. Objective 2: Identify novel sources of host plant resistance in spinach to the new and emerging priority diseases, continue selection and improvement of host plant resistance to leaf miner, and elucidate genetic variation for low oxalic content to improve bioavailability of iron in fresh product. Improved spinach germplasm and/or finished varieties will be released and incorporated into the ARS National Plant Germplasm System. Objective 3: Identify novel sources of host plant resistance in melon to Cucurbit yellow stunting disorder virus and other priority diseases of melon, determine their genetic bases and evaluate potential for higher levels of resistance through pyramiding of non-allelic resistance genes. Improved cantaloupe and honeydew germplasm and/or finished varieties will be released and incorporated into the ARS National Plant Germplasm System.

Approach:
Objective 1: Collect, identify, characterize, and evaluate wild and unadapted germplasm of lettuce. Evaluate germplasm for new sources of resistance to viruses (lettuce dieback), fungi (downy mildew, lettuce drop, powdery mildew, Verticillium wilt), bacteria (bacterial leaf spot, corky root), and insects (lettuce aphid, leafminer). Evaluate lettuce for differential pre- and postharvest survival of E. coli O157 on lettuce germplasm. Improve phytonutrient content of lettuce. Enhance germplasm, develop improved and elite populations via selection, hybridization and backcrossing. Determine heritability of host plant resistance traits. Determine inheritance and linkage relationships of phenotypic and molecular markers. Objective 2: Collect, identify, characterize, and evaluate unadapted germplasm of spinach. Evaluate germplasm for new sources of resistance to downy mildew and leafminer insect. Reduce oxalate content of spinach. Enhance germplasm, develop improved and elite populations via selection, hybridization and backcrossing. Determine heritability of host plant resistance traits. Determine inheritance and linkage relationships of phenotypic and molecular markers. Objective 3: Collect, identify, characterize, and evaluate wild and unadapted germplasm of melon. Evaluate germplasm for new sources of resistance to Cucurbit yellow stunting disorder virus and powdery mildew. Enhance germplasm, develop improved and elite populations via selection, hybridization and backcrossing. Determine heritability of host plant resistance traits. Determine inheritance and linkage relationships of phenotypic and molecular markers.

Last Modified: 10/1/2014
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