Cornell/Geneva Apple Rootstock Evaluations
Plantings 1997 and 1998; Snyder Farm, Pittstown, New Jersey
New Jersey Agricultural Experiment Station, Hunterdon County Board of Chosen Freeholders
Winfred P. Cowgill, Jr., Jeremy Compton, Gary Donato
Two separate plantings were established at the Rutgers University, Snyder Research and Extension
Farm to evaluate two advanced selections from the Cornell/Geneva breeding program.
Five cultivars on CG30 are being compared with the same five on M26 in a replicated randomized
block experiment, which was established in 1997. Cultivars include Myra Red Fuji, Braeburn,
Imperial Gala, Gingergold, and Morrans JonaGoRed. The trees are being trained to a Central Leader
style with a single metal stake at each tree for support. Drip irrigation was installed at the time of
Leaders were left unheaded but trained to the poles with a tapener. Minimal dormant pruning was
done to correct structural defects, which consisted of a few selective pruning cuts of 'nuisance'
branches. Bending with plastic limb spreaders of scaffold branches was also performed as necessary
in May to maintain desirable tree structure.
Due to the fact that this trial was interplanted with the 1994 NC-140 Semi-Dwarf Rootstock
trial, many of the horticultural practices followed such as irrigation, nutrition, and the spray program,
are dictated by the needs of that planting.
Because of a severe regional drought, no measurable amounts of rainfall occurred between the
end of May and the end of August. Irrigation was applied on a weekly basis beginning 18 May and
continuing on a 7-day schedule until 14 September.
All nutrients were applied as per 1998 NC-140 Semi-Dwarf foliar and soil test results.
Foliar nutrients: zinc, magnesium sulfate, manganese sulfate, urea, calcium and boron were applied.
Soil applied nutrients consisted of only 30 lb/A (actual) N broadcasted this season.
The trial was maintained following New Jersey's IPM spray schedule for a bearing, fresh-market
block, utilizing weekly scouting, pheromone traps, onsite weather and Skybit predictions. A minimal
crop provided no unusual disease or pest problems this year.
An application of Lorsban 50WP (3 lb/100) was made on 9 Aug. for dogwood borers.
On 16 Sept. Hurricane Floyd hit our site with 23 mph sustained winds and contained gusts up to 65
mph. It also dropped an estimated 10.57" of rain on our site. No crop or tree damage occurred.
All data is preliminary as final data collection and statistical analysis is still pending.
Data and observation indicates a variation of size and precocity between rootstocks and rootstock/
cultivar combinations. CG 30 has produced a larger, more vigorous tree at this point on all cultivars in
every replicate. Breaburn on both stocks displays moderate vigor, and retained the heaviest crop this