Project Number: 1910-21000-023-01
Project Type: Trust

Start Date: May 01, 2003
End Date: Apr 30, 2006

Objective:
Investigate the resistance or tolerance of Geneva apple rootstocks to apple replant disease at several grower sites in Washington State, and evaluate the genetic interactions between apple rootstocks and beneficial flourescent pseudomonads as an alternative to soil fumigants.

Approach:
Establish at least 6 field trials over the period of four years. One major requirement is that the trials fit into a commercial setting (i.e. large enough to be managed by growers and of economical value to growers). The establishment of such trials will depend on the availability of rootstock liners in large enough quantities to be tested. There are three phases within this objective: 1) propagation of rootstocks and tree design, 2) Establishment of trials, and 3) Data collection at the sites (data will include yearly trunk cross sectional area, yield, growth characteristics, microbial counts, etc.). These trials will be established in locations with a documented history of replant disease. We will compare performance between rootstocks planted in fumigated vs non fumigated soils. We will test several advanced selections from the Geneva breeding program for genetic interaction with beneficial Pseudomonads. Initially, our program in Geneva will ship liners to be tested in Dr. Mazzola's lab (Wenatchee, WA) and during the process we will acquire expertise to perform such experiments in-house. If significant differences are found among advanced selections, we will test half sib populations and study the inheritance of such interactions.