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United States Department of Agriculture

Agricultural Research Service

Title: Inocula and Media Affect Root-Knot Nematode Infection of Peach Seedling Roots

Authors
item Lu, Zhen-Xiang - LETHBRIDGE RES. CEN., CN
item Reighard, G - CLEMSON UNIVERSITY
item Nyczepir, Andrew
item Beckman, Thomas

Submitted to: Journal of American Pomological Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2000
Publication Date: N/A

Interpretive Summary: Root-knot nematodes are important pests of peach in the U.S. and other parts of the world. Meloidogyne incognita and M. javanica are the predominant species on peach. The continued evaluation of peach germplasm for resistance to root-knot nematodes is necessary for development and utilization of resistant rootstocks throughout the SE and world. The long generation time and large plot size of peach trees limit the efficiency of root-knot nematode resistance evaluation under conventional orchard trial conditions. In vitro testing methods have been developed to increase screening efficiency, but this required tissue culture facilities and additional technical expertise not readably available to everyone. Evaluation of peach seedlings for nematode resistance under greenhouse conditions would be a practical and reliable approach after it was determined what the optimum conditions for nematode infection and plant growth were. Six initial root-knot nematode population densities (Pi) (comparing M. incognita and M. javanica) and 4 potting media were used to evaluate nematode infection on Lovell cloned peach seedlings under greenhouse conditions. An initial root-knot nematode population density of 4,000 eggs was needed to produce reliable infection on peach roots. Sand vermiculite was a suitable medium for nematode infection and reproduction on peach. These data provide useful insights into the evaluation of Prunus germplasm for resistance to root-knot nematodes. This information was necessary for determining the most efficient initial nematode inoculum density and optimum potting medium for nematode infection and peach growth under greenhouse conditions.

Technical Abstract: Six root-knot nematode (Meloidogyne incognita and M. javanica) initial population densities (Pi) (i.e., 0; 2,000; 4,000; 6,000; 8,000; and 10,000 eggs per 1,200 cc soil) and four potting media (sand, sand/vermiculite, vermiculite, and Fafard) were used in evaluating nematode infection of cloned seedlings of Lovell peach rootstock under greenhouse conditions. No differences in plant height, shoot dry weight, and dry root weight were detected among the different Pi and media treatments for both nematodes, except that seedlings grown in Fafard medium were significantly larger. Results indicate that a Pi of 4,000 eggs per 1,200 cc soil and using sand/vermiculite medium produced the most reliable data when evaluating peach seedlings for root-knot nematode resistance under our greenhouse conditions.

Last Modified: 12/26/2014