Malheur Experiment Station Information for Sustainable Agriculture

Sweet corn and supersweet corn varieties were evaluated for agronomic and processing performance for use in the Treasure Valley of Oregon.

Two trials were conducted on an Owyhee silt loam following sugar beets. The field was worked into 30-inch beds in the spring of 1997. Alachlor (Partner) at 3 lb ai/acre was broadcast and incorporated by rain on April 30. Nineteen supersweet corn (Sh2) and 21 sweet corn (Su1) varieties were planted in separate trials. Each trial had a randomized complete block design with five replicates. The seed had been treated with standard fungicide seed treatments applied by the respective companies. The supersweet corn varieties were planted on May 1 and the sweet corn varieties on June 3 to avoid cross pollination between the two types. Seed was planted at a 2-inch depth using an Amalco Cone Seeder on a John Deere 77 Flexi Planter. The trials were furrow irrigated on alternate furrows immediately after planting to assure uniform emergence. Thereafter the field was irrigated as necessary.

A soil sample taken on May 27, 1997, showed a pH of 6.9, 1.7 percent organic matter and 87 lb of available-N in the top two feet of soil. The field was sidedressed with urea at 200 lb N/ac on June 11. The field was cultivated on June 3, and again on June 11 immediately after the urea was sidedressed.

Emergence counts were made on May 12, May 14, and May 16 for the supersweet corn and on June 23 for the sweet corn. The supersweet corn plots were thinned on May 29 and the sweet corn plots were thinned on July 25 to 24,000 plants/acre (1 plant every 8.71 inches). Final stand counts were taken after thinning in each plot.

Starting on July 5, the silk stage was evaluated for 20 plants in one of the middle two rows of each plot in the first replicate. Varieties were considered to be at the mid-silk stage when 40 to 60 percent of the plants were silking. About 16 days after the mid-silk stage, ear samples from the border rows were taken and analyzed for moisture content to determine the stage of maturity. The target ear moisture content for harvest was 78 percent for the supersweet corn varieties and 71 percent for the sweet corn varieties.

All ears in the central 15 feet of the middle two rows in each plot were picked and weighed. A 10-ear subsample was weighed, shucked, weighed, and evaluated for length, maximum diameter, diameter 6 inches from the base, and kernel row number. Ear taper was calculated by the difference between the maximum diameter and the diameter at 6 inches from the base. Ear taper is a descriptive measure of ear shape; the higher the ear taper, the less cylindrical the shape of the ear.

A composite subsample consisting of five ears from each replicate of each variety (20 ears total) was taken to the American Fine Foods processing laboratory and evaluated for moisture and processing recovery. The processing recovery was calculated as the percentage of the weight of the unhusked ears that was recovered as cut corn. Processing recovery data for each variety, based on a composite sample, were not replicated. Degree-days were measured and calculated by a biophenometer (Omnidata International, Logan, UT) at the Malheur Experiment station.

Data were analyzed by analysis of variance. Means separation was determined by the protected least significant difference test.

Results and Discussion

Emergence for the supersweet corn started on May 9. Varieties Skipper and Crystal had the highest stands on the first count on May 12 (Table 1). Final stand counts on May 16 ranged from 36 to 95 percent and averaged 76 percent. Crystal, Bandit, and Skipper had among the highest stands on May 16. Stand counts after thinning showed plant populations to be lower than the target of 24,000 plants/ac.

Yields of unhusked ears ranged from 9 to 13 tons/acre (Table 2). Shaker, XPH3129, and Marvel were among those with the highest yields. HMX5375, Assure, Maverick and XPH3129 were among those with ears with the least taper (most cylindrical ears). Recovery of cut corn ranged from 25 to 47 percent among varieties. XPH3129, FMX435, Marvel, and Contender were among those with the highest cut corn yields.

Emergence for the sweet corn varieties started on June 10 and plant stands ranged from 64 to 96 percent on June 23 (Table 3). Plant populations after thinning were close to or at the target of 24,000 plants/acre for most varieties. Plant populations of less than 23,000 plants/acre were associated with final emergence of less than 80%.

Yields of unhusked ears ranged from 6.4 to 10.6 tons/acre. Excalibur, EX8410377, Chase and StylePak had ears among those with the least taper (most cylindrical ears). Recovery of cut corn ranged from 31 to 48 percent. Missing data for recovery was due to delays in processing of some of the sweet corn variety samples which rendered those samples unusable. EX8414297 and EX8410367 were among those with the highest cut corn yields.

Table 1. Supersweet corn stand counts for corn planted on May 1 with emergence starting on May 9. Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1997.

Variety	Seed source1	Stand count
		May 12	May 14	May 16
		--------------- % ---------------
Shaker	1	17.3	73.5	79.5
XPH3129	1	15	65.8	75.7
Marvel	5	29	68	73.3
FMX435	2	21.8	63	69.2
SS Jubilee	3	17.3	66.7	77.0
Contender	5	35.2	68.5	72.2
Endeavor	1	39.5	82.5	85.5
Bandit	2	46.8	91.5	92.5
Assure	5	25.7	64.3	67.8
Lexus FM	2	15	72.8	80.3
Crystal	1	55.2	90.3	95.2
Zenith	2	38.7	67.3	74.2
GSS 7831	3	25.8	64.2	68.2
Skipper	5	57.3	87.3	89.7
HMX5375	2	21.7	60	66.5
Trigger	5	40.2	78.5	81.0
Sheba	1	45.3	80	83.3
2610A	4	7.7	29.7	36.0
Maverick	1	35.5	77.7	82.3
Average		31.1	71.1	76.3
LSD (0.05)		9.6	8.6	8.6
1Sources: 1: Asgrow, 2: Harris Moran, 3: Rogers/Sandoz, 4: ScottSeed,  5: Crookham

Table 2. Plant development, yield, and ear characteristics of supersweet corn varieties, Malheur Experiment Station,

Oregon State University, Ontario, Oregon, 1997. 

Variety	Seed source1	Days to mid-silk2	Days to harvest2	Degree-days to harvest3	Plant Pop.4	Yield5	Harvest date	Ear weight	Ear length	Ear diam.	Taper6	Rows	Moisture	Recovery7	Cut corn yield
					plants/acre	tons/acre		lb	--- inches ---			#	----- % -----		t/ac
Shaker	1	65	84	1,525	19,863	13.0	July 31	0.54	8.8	1.8	0.39	16.5	78.4	25	3.3
XPH3129	1	73	92	1,723	19,980	12.3	Aug. 8	0.85	9.3	2.2	0.37	18.3	77.2	47	5.8
Marvel	5	65	85	1,548	20,444	12.0	Aug. 1	0.77	8.9	2.2	0.42	18.5	80.5	40	4.8
FMX435	2	69	90	1,667	19,166	11.9	Aug. 6	0.80	8.8	2.2	0.48	17.4	76.2	45	5.4
SS Jubilee	3	70	90	1,667	20,677	11.8	Aug. 6	0.69	8.3	2.0	0.47	17.1	75.9	39	4.6
Contender	5	63	83	1,507	18,818	11.5	July 30	0.75	8.8	2.2	0.45	16.5	77.7	42	4.8
Endeavor	1	64	85	1,548	22,070	11.4	Aug. 1	0.68	8.4	2.1	0.46	17.8	80.0	36	4.1
Bandit	2	68	89	1,642	21,257	11.0	Aug. 5	0.70	7.9	2.1	0.53	17.7	78.5	40	4.4
Assure	5	72	91	1,696	20,328	10.9	Aug. 7	0.64	8.7	1.8	0.33	17.1	78.4	36	3.9
Lexus FM	2	72	90	1,667	20,096	10.8	Aug. 6	0.61	8.3	1.9	0.44	18.9	71.0	37	4.0
Crystal	1	72	91	1,696	21,025	10.8	Aug. 7	0.61	8.0	1.9	0.44	17.0	74.9	39	4.2
Zenith	2	72	91	1,696	19,399	10.8	Aug. 7	0.55	7.5	1.7	0.40	17.3	77.0	33	3.6
GSS 7831	3	66	85	1,548	18,353	10.7	Aug. 1	0.66	8.0	2.1	0.48	17.7	78.9	37	4.0
Skipper	5	72	90	1,667	21,838	10.6	Aug. 6	0.62	8.5	1.9	0.48	17.6	76.4	30	3.2
HMX5375	2	72	91	1,696	19,631	10.4	Aug. 7	0.57	7.9	1.7	0.32	17.4	75.9	32	3.3
Trigger	5	70	90	1,667	18,934	10.3	Aug. 6	0.69	8.8	2.0	0.43	18.1	76.3	41	4.2
Sheba	1	62	78	1,388	18,586	10.3	July 25	0.59	8.6	2.0	0.49	14.5	79.4	31	3.2
2610A	4	67	89	1,642	13,823	9.5	Aug. 5	0.69	8.3	2.0	0.45	16.6	75.3	36	3.4
Maverick	1	72	91	1,696	18,934	9.1	Aug. 7	0.56	8.2	1.7	0.36	14.9	74.2	38	3.5
Average		69	88	1,626	19,643	11.0		0.66	8.4	2.0	0.43	17.2	77.0	37.1	4.1
LSD (0.05)					3,316	1.0		0.05	0.2	0.1	0.07	NS
1Sources: 1: Asgrow, 2: Harris Moran, 3: Rogers/Sandoz, 4: ScottSeed, 5: Crookham 2From emergence.
3Degree-days (50 - 86 OF) from emergence. 4After thinning. 5 Yield of unhusked ears.
6 Maximum diameter minus diameter 6 inches from the base. 7 Percentage of unhusked ear yield recovered as cut corn.
8 NS: not significant.

Table 3. Plant development, yield, and ear characteristics of sweet corn varieties, Malheur Experiment Station, Oregon State University, Ontario, Oregon, 1997. 

Variety	Seed source1	Days to mid-silk2	Days to harvest2	Degree- days to harvest3	Emergence June 23	Plant population4	Yield5	Harvest date	Ear weight	Ear length	Ear diam.	Taper6	Rows	Moisture	Recovery7	Cut corn yield
					%	plants/acre	tons/acre		lb	--- inches ---			#	------ % ------		tons/acre
EX8410367	1	56	80	1,688	82.8	25,323	10.6	Aug. 29	0.79	8.7	2.1	0.36	17.5	73.7	43	4.6
EX8414297	1	54	79	1,667	88.5	25,091	10.0	Aug. 28	0.69	8.1	2.2	0.66	17.9	68.8	47	4.7
EX8410347	1	53	80	1,688	93.7	23,116	9.8	Aug. 29	0.71	8.5	2.0	0.41	18.2	71.7	39	3.8
HMX5371	2	55	80	1,688	74.5	22,767	9.5	Aug. 29	0.64	8.2	2.0	0.47	19.3	71.9	36	3.4
EX8410357	1	53	77	1,624	93.8	23,232	9.4	Aug. 26	0.70	8.2	2.1	0.44	19.0	74.6	46	4.3
EX8410377	1	55	79	1,667	96.0	23,581	9.4	Aug. 28	0.68	9.2	1.9	0.22	19.2	71.8	37	3.5
HMX5372	2	48	80	1,688	74.8	22,070	9.3	Aug. 29	0.78	9.0	2.1	0.44	17.9	71.0	46	4.3
XPH3125	1	52	76	1,604	84.0	24,626	9.0	Aug. 25	0.68	8.5	2.0	0.40	14.4	70.3	45	4.0
G. Jubilee	3	54	77	1,624	84.0	22,419	8.9	Aug. 26	0.62	8.4	1.9	0.42	17.9	71.7	36	3.2
Fantasia	1	50	73	1,539	88.2	24,510	8.6	Aug. 22	0.52	8.2	1.7	0.33	16.8	74.0	31	2.7
HMX5373	2	56	84	1,777	89.2	25,091	8.5	Sept. 2	0.66	8.2	2.1	0.54	18.5	72.8
GH 1887	3	45	73	1,539	83.0	24,045	8.4	Aug. 22	0.54	8.5	1.8	0.39	19.4	74.7	33	2.8
26,717	4	53	76	1,604	85.0	23,232	8.4	Aug. 25	0.57	8.3	1.9	0.45	18.1	69.7	34	2.9
Sequel	1	55	77	1,624	82.3	23,813	8.4	Aug. 26	0.66	8.3	2.0	0.40	17.6	74.8	38	3.2
Chase	1	51	72	1,516	89.8	23,464	8.2	Aug. 21	0.57	8.4	1.8	0.28	14.0	72.0	42	3.4
26490A	4	59	85	1,798	81.8	23,232	7.9	Sept. 3	0.74	9.2	2.0	0.33	18.7	71.3
Legacy	2	58	84	1,777	75.0	22,884	7.7	Sept. 2	0.70	8.7	2.0	0.36	21.6	69.6
StylePak	2	57	85	1,798	90.1	24,045	7.6	Sept. 3	0.66	7.6	1.9	0.30	21.3	71.1
Excalibur	2	56	84	1,777	76.2	21,141	7.4	Sept. 2	0.69	8.4	1.8	0.17	22.1	69.6
Lexus	2	51	76	1,604	79.0	22,535	7.3	Aug. 25	0.56	8.3	1.8	0.38	16.1	71.8	48	3.5
HMX5374	2	59	85	1,798	64.2	21,838	6.4	Sept. 3	0.67	7.9	2.0	0.43	19.2	71.9
Average		54	79	1,671	83.6	23,431	8.6		0.7	8.4	2.0	0.39	18.3	71.8	29	2.6
LSD (0.05)					7.0	2,119	1.1		0.04	NS	0.1	0.15	3.5
1Seedsources: 1: Asgrow, 2: Harris Moran , 3: Rogers/Sandoz , 4: Scottseed
2From emergence. 3Degree-days (50 - 86 OF) from emergence. 4After thinning. 5 Yield of unhusked ears.
6 Maximum diameter minus diameter 6 inches from the base. 7 Percentage of unhusked ear yield recovered as cut corn. 8NS: not significant

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Malheur Agricultural Experiment Station

Last updated  Tuesday July 30, 2002 .