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United States Department of Agriculture

Agricultural Research Service

Research Project: VEGETABLE GRAFTING FOR RESISTANCE TO SOILBORNE DISEASES

Location: Subtropical Plant Pathology Research

2009 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
In the past year, we found that a number of USDA developed rootstocks may be useful in resistance to the common root-knot nematode Meloidogyne incognita. Furthermore, these rootstocks were compatible with the scion (top part of the plant). It is possible to graft these rootstocks to varieties having no resistance to M. incognita root-knot nematode.

Demonstrated mechanical grafting of peppers is possible. Developed a specialized room with environmental conditions that favor healing of scion/rootstock and increased successful graft combinations.

Set up first experiments using a commercial pepper variety grafted on nematode resistant rootstocks and grown in non fumigated soil. We are repeating these experiments to test the reliability of the rootstocks.


4.Accomplishments
1. Current Results of Bell Pepper Grafting Research. We found that open pollinated sources of pepper germplasm can impart root-knot nematode resistance by grafting susceptible commercial varieties with desirable horticultural properties but also limited nematode resistance as upper portions of the plant. The first greenhouse studies were established with grafted peppers planted in nonfumigated soil. These studies seek to find the influence of indigenous populations of organisms on the growth and development of grafted pepper plants.

2. Greenhouse Studies with Commercial Tomato Rootstocks. Concluded initial greenhouse study of commercial tomato rootstocks grown in nonfumigated soils. We found several rootstocks with promising resistance to root-knot nematodes. This study was repeated twice and is in the process of having data analyzed.

3. Field Studies of Grafted Tomato and Musk melon. Concluded with collaborators initial field studies on tomato and musk melon growth in fumigated and non fumigated soils. Data is currently being analyzed.


Review Publications
Burelle, N.K., Bausher, M.G., Rosskopf, E.N. 2009. Greenhouse evaluation of capsicum rootstocks for management of meloidogyne incognita on grafted bell pepper. Nematropica 39:121-132.

Last Modified: 8/19/2014
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