Malheur Experiment Station Information for Sustainable Agriculture

The Oregon potato variety development program evaluates potato lines through the selection process until they are discarded or, as occurs more rarely, named and released as a variety. The Malheur Experiment Station is one of the sites conducting the Oregon Preliminary, Oregon Statewide, and Western Regional trials. Over 100 selections were included in these trials at Ontario in 1999. This report summarizes the performance of potato varieties and lines at Ontario in 1999.

The Preliminary Yield Variety Trial, the Statewide Variety Trial, and the Western Regional Early and Late Harvest Trials were planted April 19 through 21, 1999, in the same field of Owyhee silt loam and received the same management practices throughout the season. The Preliminary Yield Trial included 5 standard varieties and 101 numbered selections in 20-hill plots with 2 replications. The Statewide Variety Trial had 5 standard varieties and 19 numbered selections, in 30-hill plots replicated 4 times. The Western Regional Early Harvest Trial had 4 standard varieties and 13 numbered selections, and Late Harvest Trial had 4 standard varieties and 11 numbered selections, in 30-hill plots with 4 replications. All trials were arranged in a randomized complete block design and were furrow irrigated.

Treated 2-oz seed pieces were planted 9 in deep with rows spaced 36 in apart. Urea was sidedressed after planting at 114 lb N/acre. Weeds were controlled with the herbicides Prowl at 1 lb ai/acre and Dual at 2 lb ai/acre applied May 17 and incorporated with a rolling cultivator. The crop was protected from disease by aerial application of registered fungicide. No late blight was present in 1999.

The Early Harvest Trial potato vines were shredded with a flail mower August 8, and tubers were lifted with a mechanical potato digger and picked by hand into burlap bags on August 9. On September 17, the vines were flailed on the other trials. The Preliminary Yield Trial was harvested September 24, the Western Regional Late Trial September 27, and the Statewide Trial was harvested September 28. Tubers were lifted with a mechanical potato digger and picked by hand into burlap bags. External tuber characteristics were noted in each plot during harvest. The potatoes were stored under tarps in a shed until they were graded into US Number One tubers (4 to 6 oz, 6 to 12 oz, and over 12 oz), US Number Two tubers (over 4 oz), tubers under 4 oz, and culls.

Twenty-tuber samples of each variety in each plot were taken from all trials and placed in storage at 45 ^oF. In December, the tubers were evaluated for specific gravity and fry color. Specific gravity was measured by the weight-in-air, weight-in-water method. Ten large (usually over 10 ounces) tubers from each plot were cut lengthwise and inspected for internal defects. The data on external characteristics and internal defects are not presented in this report. Data on yield, grade, and processing quality were evaluated using NCSS software and ANOVA. Where significant differences were present, the LSD (0.05) was calculated.

Preliminary Yield Trial. Most of the entries in this trial were selections from crosses made at Aberdeen, Idaho, in 1994 and 1995 (Table 1). Yields were acceptable, but most of the selections had many off-type, rough, or growth cracked tubers. After reviewing data from Hermiston, Klamath Falls, Powell Butte, and Ontario, only 6 selections of the 101 tested were advanced for further evaluation in the 2000 Statewide trial. The varieties that were advanced are marked with an asterisk in the variety number column of Table 1.

Statewide Variety Trial. The overall quality and performance of entries in this trial was very good (Table 2). Russet Burbank produced a high total yield but produced many US Number Two tubers and culls. Most of the russet-skinned selections were attractive in appearance, had relatively good tuber type, produced high yields, and had fewer external and internal defects than Russet Burbank.

Ranger Russet, Atlantic, and seven experimental lines produced more than 400 cwt/acre of US Number One yield at Ontario in 1999. After reviewing data from Hermiston, Klamath Falls, Powell Butte, and Ontario, only 7 of the 19 experimental lines tested were retained for further evaluation in the 2000 Statewide trial. The varieties that were retained are marked with an asterisk in the variety number column of Table 2. The line AO85165-1 graduated from the trials and is being released as Klamath Russet. The selections AO92007-2, COO93031-3 and two tuber types of AO89128-4 were advanced to the Tri State Trial for 2000. The line AO90319-1 was advanced to a specialty trial.

Western Regional Early and Late Harvest Trials. At Ontario, Russet Burbank had among the lowest yield of US Number One tubers and among the highest yield of US Number Two tubers and culls of all entries (Table 3). In the early harvest trial, the selections A82360-7 and AC87079-3 were among the most productive of US Number One tubers at Ontario. In the late harvest trial, the selections AO92023-3, AC87084-3, CO89036-10, and TXNS296 were among the most productive of US Number One tubers at Ontario.

Varieties are dropped or selected for release based on a large number of criteria and performance at multiple sites for three or more years. Oregon, Washington, Idaho, California, Colorado, New Mexico, and Texas cooperate in the trials. After the 1999 season, the lines A88338-1 and CO89036-10 were dropped. The lines AC87084-3, AO87277-6, and NDD840-1 graduated for potential release.

The quality of advanced selections in the Oregon and regional potato variety development programs was excellent. Oregon released Umatilla and Legend Russet in 1998. Idaho released a red-skinned selection, A82705-1R, as Idarose in 1999. Idaho also released Bannock Russet and Gem Russet in 1999. Oregon is releasing two red varieties and one russet in 2000. Klamath Russet (AO85165-1) is a high yielding long russet with excellent appearance and yield in the Klamath Basin and perhaps elsewhere. Mazama and Winema are the newly released red varieties.

Table 1. Yield, grade, fry color, and specific gravity of standard potato varieties and 11 lines selected for further evaluation from the Preliminary Yield Trial, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.

Table 2. Yield, grade, fry color, and specific gravity of 24 potato varieties and selections in the Oregon Statewide Variety Trial, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.

				US Number One
Variety	Entry	Total yield	Percent No. One	Total	< 12 oz	4 to 12 oz	> 4 oz	US Number Two	Rot	Spec. gravity	Fry color, light reflectance
		cwt/acre	%	---------------------------cwt/acre-----------------------
Russet Burbank	1	498	50	248	37	191	77	133	41	1.080	37.7
Ranger	2	601	67	405	97	351	52	133	12	1.100	45.7
Shepody	3	506	70	355	100	288	42	103	5	1.090	48.1
Norkotah	4	491	65	319	116	272	36	130	6	1.099	45.0
Atlantic	5	579	81	468	83	339	75	33	3	1.092	49.6
AO85165-1	6	468	81	381	183	337	34	47	6	1.081	41.3
AO87277-6	7*	632	74	468	78	367	53	99	11	1.096	46.3
AO89128-4	8*	515	60	311	28	205	80	115	9	1.099	57.1
AO90014-1	9	434	74	322	37	241	63	38	12	1.091	52.6
AO90319-1	10	491	72	354	47	235	88	42	7	1.095	42.1
AO91812-1	11*	581	77	445	49	309	78	39	19	1.096	50.0
AO92007-2	12*	559	73	409	106	351	44	90	15	1.088	44.1
AO92017-6	13*	602	59	355	63	274	36	185	27	1.094	47.2
COO93031-3	14*	577	78	451	160	364	43	76	7	1.083	39.2
AO92252-1	15*	521	82	426	105	372	29	65		1.095	49.0
AO92378-1	16	464	81	377	127	309	34	50	3	1.098	50.1
AO93317-5	17	595	80	475	56	354	49	64	7	1.090	48.8
AO94169-8	18	511	72	366	119	319	41	91	13	1.077	34.5
AO94203-3	19	384	83	320	171	295	15	42	7	1.090	48.1
AO94204-2	20	468	83	390	205	352	22	45	11	1.084	36.6
AO94204-7	21	506	68	345	139	307	21	129	11	1.078	44.7
AO94205-1	22	512	70	360	28	223	97	51	4	1.087	49.1
AO94218-1	23	576	77	443	61	350	44	67	23	1.080	43.5
AO94224-1	24	533	74	396	72	322	48	71	18	1.090	42.9
Mean		525	73	383	94	289	50	81	10	1.090	45.5
LSD (0.05)		2	10	73	50	82	23	46	23	0.005	3.1

*retained in the Statewide Trial for 2000

Table 3. Yield, grade, fry color, and specific gravity of potato varieties and selections in the Western Regional Early and Late Harvest Trials, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1999.