Malheur Experiment Station Information for Sustainable Agriculture

Potato Variety Trials at Ontario

Eric P. Eldredge, Clinton C. Shock, and Lamont D. Saunders
Malheur Experiment Station
Oregon State University
Ontario, OR, 1998

Introduction

Potato variety development at Malheur Experiment Station helps identify clones that are adapted to irrigated production in the western Treasure Valley. Currently, most of the acreage grown is under contract for processing, with very little acreage for fresh pack or open market, and very little storage on growers' farms. Most of the contracted production is for early harvest, beginning the second week of August, to start up the processing plants. The main varieties currently grown are Russet Burbank, Shepody, and Ranger Russet, with small acreages of newer varieties contracted by the processors to test their suitability. To be successful, a new variety should have high yield, be free of tuber defects, have good processing quality, and produce most of its yield in US #1 grade tubers.

Procedures

Three furrow-irrigated potato variety trials were grown at Malheur Experiment Station in 1998. The Western Regional trial, with 17 varieties, represents the clones closest to release and newly released varieties, with the current standard varieties included as checks. The Oregon Statewide trial, with 30 varieties, were selected out of previous years' research for further evaluation. The Preliminary Yield Trial 2, with 42 varieties, tests the clones selected from single hill trials.

Trials were planted May 4, 1998, in a field that had been in winter wheat the previous year. After wheat harvest the stubble was chopped, the field was irrigated, disced, 100 lb/acre of P and 20 lb/acre of N were broadcast, ripped with Telone II at 22 gal/acre and fall-bedded on 36-inch rows.

Two ounce, hand-cut seed pieces, treated with Mancozeb at cutting, were planted on 9 in spacing with Thimet 20 G at 1.7 oz/100 ft of row (15.7 lb/ acre). An early April soil test showed 68.3 lb N/acre as nitrate and ammonium in the top 2 ft of soil. On May 7, potato rows were sidedressed with 46 lb N/acre in the form of urea prills. On May 19, Prowl 3.3 EC at 1 lb ai/acre plus Dual 8E at 2 lb ai/acre was applied for pre-emergence weed control and incorporated May 20 with a Lilliston rolling cultivator. On June 4, the variety trials were treated with Matrix at 1 oz/acre plus Sencor 4 at 1 pt/acre for control of emerged weeds and soil residual weed control activity. Plots were furrow-irrigated 14 times between June 8 and August 18. Vines were removed by flailing September 25.

The variety plots were dug October 6 and 7 with a two-row lifter, visually evaluated in the row, and picked up by hand and placed in burlap sacks. Sacks were stored under tarps in a barn until grading in early October. A twenty-tuber sample from each plot was placed into refrigerated storage that was slowly brought down to 47 ⁰F. In mid-December, samples were removed from storage and the specific gravity, tuber defects, and fry color were recorded.

Results and Discussion

The 1998 growing season was not favorable for potato production at Ontario. The growing season started out cooler and wetter than normal. The month of May had 4.55 in of precipitation compared to the 50-year mean of 1.02 in. Planting was delayed by rainy weather until May 4, and emergence of potato sprouts was slow and uneven. May had 29 percent fewer and June had 18 percent fewer growing degree days (50-86 ⁰F) than the previous 10-year means. The potato growth during June was developing very well, but delayed by the cool weather. Then on July 4, a severe hail storm dropped 1/2 in hailstones for half an hour accompanied by strong wind and rain. The variety trial received severe hail damage with vines nearly defoliated and deeply pitted on the upwind side.

The months of July and August were hotter than normal. The Malheur Experiment Station NOA weather station recorded 11 days with maximum air temperatures of 100^o F or higher compared to the 50-year mean of 5 days for the entire year. There were far more degree days in the above optimal range (86 to 104 ⁰F) in 1998 compared to the previous 8-year mean; 70 percent more in July and 29 percent more in August. The hot weather in July and August additionally stressed the potatoes during tuber bulking.

Preliminary Yield Trial. Most of the entries in this trial were selections from crosses made at Aberdeen, ID, in 1992 through 1994. Several entries had acceptable yield, but several of the selections, including Russet Burbank and Shepody, had many off-type, rough, or growth-cracked tubers. Shepody ranked relatively high in total yield (Table 1) but produced many small 4- to 6-oz tubers. Russet Burbank had average yield, much of which was below 6 oz, and had relatively poor specific gravity. Despite the severe stresses of the 1998 growing season, AO94203-3 produced 224 cwt/ac U.S. Number One tubers larger than 12 oz, significantly more large Number Ones than any other variety in this trial at this location. Entries selected from this trial were advanced to the Statewide Variety Trial.

Statewide Variety Trial. Russet Burbank produced a relative low total yield (Table 2), and the U.S. Number One yield of Russet Burbank was nearly all 4 to 12 oz tubers at Ontario in 1998. COO93031-1 produced 168 cwt/acre U.S. Number Ones larger than 12 oz, significantly more large Number Ones than any other variety in this trial at this location.

Western Regional Trial. Russet Burbank had low yield of U.S. Number One tubers and among the highest yield of U.S. Number Two tubers and culls of all entries (Table 3). The selection TX1385-12RU was among the most productive of total yield and marketable yield, but it had marginal fry color and specific gravity for processing. The line A88338-1 was also highly productive at Ontario, as were the round white chipping variety Avalanche and Ranger Russet. Ranger Russet also had among the highest specific gravity.

Four Texas and two Colorado line selections of Russet Norkotah were included in this trial. All had later vine maturity than the standard Norkotah entry (data not shown). The Colorado selections (CORN-3 and CORN-8) and the Texas selection (TXNS 223) were entered in the regional trial for the first time in 1997. In 1997 trials, all Norkotah line selections were as productive or better than standard Russet Norkotah, as was the case again in 1998.

Summary

The quality of advanced selections in the Oregon and regional potato variety development programs was excellent. Oregon formally released Russet Legend and Umatilla Russet in 1998. Idaho released a red-skinned selection, Idarose; and two russeted selections, A81473-2 and A8495-1, in 1998. Based on evaluation of the russet skinned selections at Ontario, Umatilla Russet and Russet Legend have promise for processing based on marketable yield, high percentage of U.S. Number One tubers, high specific gravity, and light fry color.

Table 1. Yield, grade, fry color, and specific gravity of forty-two potato varieties and selections in the Preliminary Yield Trial 2, Malheur Experiment Station, Oregon State University, Ontario, OR, 1998.

Table 2. Yield, grade, fry color, and specific gravity of thirty potato varieties and selections in the Oregon Statewide Variety Trial, Malheur Experiment Station, Oregon State University, Ontario, OR, 1998.

Table 3. Yield, grade, fry color, and specific gravity of seventeen standard potato varieties and lines in the Western Regional Trial, Malheur Experiment Station, Oregon State University, Ontario, OR, 1998.

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Last updated  Tuesday July 30, 2002 .