David Scantlin

A replicated strip trial of commercial sugarbeet varieties was conducted in 1999 on Driscoll Brothers Farms in the Blue Gulch growing area, which is northwest of Castleford, Idaho. The purpose of this trial was to test the performance of commercial varieties grown in large plots under commercial cultural conditions. An additional purpose was to compare these results with the University of Idaho variety trials that are conducted yearly.

The nine varieties tested were Owyhee, Oasis, Canyon, Dillon, Sierra and PM21 produced and sold by Novartis Seeds (Hilleshog), Inc., and Beta 8220, Beta 8757, and Beta 8468 produced and sold by Betaseed, Inc. Field size restrictions and seed availability at the time of planting limited the varieties included in the trial.

Typically the yield in this growing area averages approximately 30 tons/acre. Most fields in the area are irrigated with pivots, but this field was irrigated with hand lines. The field had been treated with Vapam the previous fall and was fall bedded. All seed was large raw and planted at a 6-1/8 inch spacing on March 26 and 27 using a John Deere MaxEmerge planter. Strip plots were randomized within each of four replications. The trial area was 52.2 acres, with 5.8 acres per variety.

The trial was harvested on November 4 and 5 with a Parma 6-row lifter-loader. Two sugar samples were taken from each truck which totaled 8 samples per plot and 32 samples for each variety over the whole test. Trucks and load weights were separated by variety and individual plot. Data was analyzed as a randomized complete block design with 9 treatments and 4 replications.

The results of the trial are summarized in Figures 1, 2, and 3. Yields were normal for the area and ranged from 33.8 tons/acre for Beta 8220 to 28.5 tons/acre for PM21. There were no significant differences in this test for root yield among Beta 8220, Owyhee, and Oasis. Grouping of varieties was similar for both root yield and estimated recoverable sugar (ERS) per acre. Although Beta 8757 changed place in the ranking for ERS/acre, there were no significant differences among Canyon, Dillon, Beta 8757 or Sierra for either root yield or ERS/acre.

The spring of 1999 was very cold and there were reactions to the cold in two varieties. PM21 had approximately 6-8% bolting in every replication and there was about 1% bolting in Dillon. Bolting may not have occurred had the planting date been later or if the weather had been warmer. The bolting may have contributed to the lower yields in PM21.

Performance of the same varieties from the University of Idaho variety tests in the 3-location summary and the Blue Gulch test are compared in Figures 4 and 5. The UI 3-location summary is for the variety trials at the Aberdeen R&E Center, Jerome County, and the Oregon State University Malheur Experiment Station, and is an indicator of variety stability across several environments. The relative values for root yield and ERS/acre were similar for the two data sets with the exception that Dillon and Owyhee switched positions in the ranking.

When making variety selections, it important to consider disease resistance, emergence, and planting temperatures in the decision making process. The best performing variety one year may not be the best in other years. There is rarely one best variety for all conditions in all years.

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Presented at the Snake River Sugarbeet Conference, Twin Falls, Idaho, January 13-14, 2000.

David Scantlin, Fieldman, Amalgamated Sugar Company, PO Box 127, Twin Falls, Idaho 83303-0127, Phone, (208) 733-4104.