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United States Department of Agriculture

Agricultural Research Service


Location: Subtropical Plant Pathology Research

2010 Annual Report

1a. Objectives (from AD-416)
Obj. 1: Identify available germplasm resistant to soilborne diseases and pests currently being controlled by pre-plant soil fumigation with methyl bromide for use as grafting rootstocks for Solanaceous vegetables, primarily tomato and pepper. Obj. 2: For selected rootstock germplasm shown to be effective for management of soilborne pests and pathogens of economic importance in the southeastern United States, describe rootstock-scion interactions that influence plant growth, fruit yield, fruit quality, and other important horticultural traits. Obj. 3: For selected rootstock-scion combinations shown to have an acceptable resistance to soilborne pests and pathogens and produce fruit of acceptable quality, evaluate under field conditions, similar to those used for commercial production, the plant growth, fruit yield, fruit quality, and other important horticultural traits that contribute to the economic feasibility of grafting.

1b. Approach (from AD-416)
Identify rootstock and scion germplasm material which have traits that resist diseases commonly found in the Southeastern U.S. currently controlled by methyl bromide. Screen available rootstock material for compatibility using current and new techniques. Select and evaluate rootstock and scion combinations for initial disease resistance and adaptation to current and new cultural technique. Determine the influence of rootstock/scion combinations on the horticultural characteristics of fruit including fruit appearance pre and post harvest quality, flavor, time to maturity, and yield. Develop techniques to evaluate the growth and development of the plant combinations under biotic and abiotic stress and evaluate grafted plant performance under varying cultural conditions.

3. Progress Report
During this report period research results indicated that we can get grafting take of peppers of 95% or better with the improved healing conditions. This increased the availability of plants to use in experiments for rootknot nematode experiments and use for field experimentation. We obtained new sources of pepper varieties for evaluation from commercial and USDA breeders for new disease and nematode experiments and found them compatible with 5 commercial varieties. Completed 3 commercial trials of tomatoes grafted on up to 10 rootstock combinations. These trials were performed with the cooperation of commercial growers under commercial conditions of care and harvesting. Set up and experiments investigating the influence of rootstocks on the etiology of Tomato Yellow Leaf Curl on tomato. Concluded with collaborators initial field studies on tomato under non fumigated soils using both conventional and certified organic conditions. Data is currently being analyzed.

4. Accomplishments
1. Open pollinated sources of tomato can impart root-knot nematode resistance when grafted as the rootstock. We found that open pollinated sources of tomato can impart root-knot nematode resistance to susceptible commercial varieties with desirable horticultural properties but limited nematode resistance. The first greenhouse studies were established with grafted tomatoes planted in nonfumigated soil. These studies seek to find the influence of indigenous populations of soil microorganisms on the growth and development of grafted tomato plants.

Last Modified: 07/20/2017
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