Sugar Enhanced & SupersweetCorn Variety Trial Results

John Strang, John Snyder & Chris Smigell

Sweet Corn Types• Normal sugary (su) – Silver Queen

– Standard sweet corn

• Sugary Enhanced (se)– Tender kernels, creamy texture, higher sugar

• Super Sweet, Shrunken-2 - Extra Sweet, Ultra Sweet, Gourmet Sweet (sh2) – Light weight shrunken/wrinkled seeds– High sugar content– Slow or incomplete conversion of sugar to starch– Crunchy kernels, less water soluble polysaccharides– Poor germination in cold soils– Type required for shipping

Sweet Corn Types

• Augmented Supersweets - XtraTender™, Gourmet Sweet™, MultiSweet™, HQ, shQ– Tender kernels, added sweetness and

longer shelf life– Only one single type of kernel on ear

Sweet Corn Types

• Synergistic - Sweet Gene™, Sweet Generation™, Sweet Breed™, Tablesweet™, Triplesweet™, seQ

– Have different types of kernels (su, se, sh2) on the same ear

– Seed vigor of su varieties – Flavor and eating quality of se varieties – High sugar content and long shelf life of sh2

varieties

Sweet Corn Types

• Genetically Modified (Transgenic) –Attribute™, Performance Series™– Varieties express the bacteria bt toxin

that kills worms feeding on the sweet corn– Performance Series varieties are tolerant

to Roundup herbicides and provide above and below ground insect control.

High Sugar Corn Isolation

• All types should be isolated from field corn and popcorn to prevent loss of sweetness– Distance

• 700’ complete isolation• 250’ some contamination, but not enough to

affect quality– Time

• 14 days difference in corn maturity

Isolation Groups• Group 1

– Standard varieties (su)– Sugary enhanced (se)– Synergistic– Sweet Breed– Table Sweet– TripleSweet– seQ– HQ

• Group 2– Supersweet (sh2)– Augmented

supersweet– Crisp N Sweet– Gourmet Sweet– MultiSweet– SummerSweet– Xtra Tender– shQ

Horticultural Research Farm, Lexington, KY

2015• Sugar enhanced &

synergistic varieties

2016• Supersweet &

augmented supersweet varieties

http://www.uky.edu/hort/documents-list-commercial-fruit-nut

Varieties Evaluated 2015Variety/Seed company Type/Maturity

Variety/Seedcompany Type/Maturity

Allure SW Bc se 75 Pay Dirt SI Bc se 62-72Mattapoiset SW W se 80 Luscious JS Bc se+ 75Silver King HR W se 82 Sugar Pearl JS W se+ 73Profit SW Bc se 70 Essence RU Bc syn 78Ka-Ching SI Bc se 73-77 Mirage HR W syn 78Whiteout SW W se 73 Cameo RU Bc syn 84Alto SI Bc se 62-72 Revelation HR BC syn 66Cuppa Joe RU Bc se 73 WH 0809 SY W tsw 80Brocade HR Bc se 82 Primus SY Bc tsw 81Trinity SI Bc se 66-72 Aspire* SY Y tsw 80Sweetness SW Bc se 68 BC 0822 SY Bc tsw 77

Abbreviations: Bc=bicolor; W=white; Y=Yellow; se=sugar enhanced; se+=sugar enhanced-plus; syn=synergistic; tsw=Tablesweet™*Attribute II type with Liberty and Touchdown herbicide tolerance

Fertilization2015

• Preplant– 100 lb N/A NH4NO3

– 18 lb K/A 0-0-60• Sidedressed

– July 1– 50 lb N/A CaNO3

2016• Preplant

– 80 lb 19-19-19/A

• Sidedressed– July 11– 36 lb N/A CaNO3

– Fertigated

Plot Characteristics2015 2016

Season Wet WetPlanted May 22 May 25Plant spacing 33” X 9” 33” X 9”Plots 20‘ long 20’ longReplications 4 4

Weed and Insect Control2015

• Cultivated 10 days after planting

• Dual II Magnum July 1

• Coragen & Brigade used for insect control

2016• Plot cultivated

• Dual II Magnum June 14

• Mustang Maxx & Baythroid for insect control

Coyote & Raccoon Exclusion• Solar powered

electric fence installed prior to harvest

Evaluation• Seedling vigor

– (1-5)• Ease of ear harvest

– (1-5)• Height to first ear

– (in)• Husk coverage

– (1-10)• Ear length & Width• Tip Fill

– (1-10)• Row Straightness

– (1-10)

Evaluation

• One ear from each replication microwaved

• Taste (1-4)– Pericarp tenderness– Kernel tenderness– Sweetness

Results 2015

• No significant difference in yields for most varieties

• Range: 1600 – 2110 dozen /A

• Synergistic and Se varieties yielded equally well

Variety/Kernel colorDays to Maturity

SeedlingVigor*(1-5)

Yield(Dozen/A)

Essence (Bc, se) 82 3 2110

Mattapoiset (W, se) 71 3.9 2080

Silver King (W, se) 75 3.5 2030

Mirage (W, syn) 77 2.9 1950

Profit (Bc, syn) 70 5 1900

Whiteout (W, se) (Std) 73 3 1880

Aspire (Y, tsw) 80 3.5 1800

*1 – 5 scale, 5 = excellent

Variety/(kernel color)

Husk Coverage (1 – 10)*

Tip Fill (1 – 10)*

Ear Length(in)

Essence (BC, Se) 10 9.3 7.5

Mattapoiset (W, Se) 9.5 9 8

Silver King (W, Se) 9 8.8 7.6

Mirage (W, Syn) 10 10 7.9

Profit (Bc, Syn) 8.5 9.5 7.4

Whiteout (W, Se) 7.5 8.3 7.5

Aspire (Y, Tsw) 9.8 7.3 8.1

*Number of ears with good husk coverage or tip fill out of 10 observed1 – 10 scale, 10 = excellent

Variety/(kernel color)

Pericarp tenderness

(1-4)*

Kernel tenderness

(1-4)*Sweetness

(1-4)*

Essence (BC, Se) 3.6 3.5 3.6

Mattapoiset (W, Se) 3.1 3.3 3.8

Silver King (W, Se) 2.9 2.9 3.1

Mirage (W, Syn) 3.1 3.3 3.5

Profit (Bc, Syn) 3.1 2.8 3.6

Whiteout (W, Se) 3.4 3.3 3.4

Aspire (Y, Tsw) 3.3 2.9 3.8

*1 – 4 scale, 1=poor, 4=excellent

Best White Corn

Best Bicolor Corn

Best Yellow Corn

Bacterial Rot

Varieties Evaluated 2016Variety/Seed company

Type/Maturity

Variety/Seed company

Type/Maturity

Munition (Std) SY W 78 XtraTender 2171 JS Bc 71Cabo SY Bc 78 Nirvana SW Bc 75Battalion* SY Bc 77 Superb MXR ST Bc 74GSS 1170 SY Y 78 Vision MXR JS Y 75AP 426 RU Bc 58 SS 3778* JS Y 76Cumberland ST Bc 77 Honor XR* ST BC 79Anthem XR SW Bc 72 SS 2742 JS Bc 75Obsession* (Std) RU Bc 79 Eden ST W 76Enchanted RU Bc 78 XTH 11274 ST Y 72Super Surprise RU Bc 74 XtraTender 20173 JS Bc 73Prestige XR* SW Bc 77 Gourmet Sweet 2171 ST BC 72

*Supersweet, all others are augmented supersweet varietiesAbbreviations: Bc=bicolor; W=white; Y=Yellow

Supersweet and Augmented Supersweets 2016

• This was another very wet season

• In general shuck coverage was the poorest in many years

• Bacterial rot was evident

Results

Munition significantly out-yieldedall other varieties tested (3200 dozen/A)

18 of 22 varieties had statistically similar yields (1370-3220 dozen/A)Excessive rainfall caused shank browning,but no loss to diseases

Variety / (kernel color)Days to Maturity

SeedlingVigor*

Yield(Dozens/A)

Munition (W) Std. 78 4.5 3220

Cabo (BC) 78 3.3 2110

Battalion (BC) 77 3 2010

GSS 1170 (Y) 78 3.6 2010

AP 426 (BC) 58 3.4 1980

Anthem XR (BC) 72 4.9 1850

Obsession (BC) Std. 79 3.9 1830

* 1 – 5 scale, 5 = excellent

Top Overall Performers

Variety / (kernel color)

Husk Coverage (1 – 10)*

Tip Fill (1 – 10)*

Ear Length (in)

Munition (W) Std. 6.5 9.8 7.5

Cabo (BC) 6.5 9.8 8.1

Battalion (BC) 5 10 7.7

GSS 1170 (Y) 6 9.5 7.5

AP 426 (BC) 8.3 9.5 8

Anthem XR (BC) 7.3 9.8 7.9

Obsession (BC) Std. 7 9.8 8*Number of ears with good husk coverage or tip fill out of 10 observed1 – 10 scale, 10 = excellent

Variety/(kernel color)

Pericarp tenderness

(1-4)

Kernel tenderness

(1-4)Sweetness

(1-4)

Munition (W) Std. 3.4 2.7 3.2

Cabo (BC) 3.5 2.5 3.2

Battalion** (BC) 3.5 3 3.8

GSS 1170 (Y) 2.9 2.7 3.5

AP 426 (BC) 3.4 2.9 3.6

Anthem XR (BC) 3.5 3.1 3.7

Obsession** (BC) Std. 3.5 3 3.8

*1 – 4 scale, 1=poor, 4=excellent** Supersweet varieties

Munition

• Best white corn• Top yielder in trial• Highest height to 1st ear• Good seedling vigor• Standard for comparison

in trial

Cabo

• Bicolor• Long ear• Good row straightness• Not much shank rot

Battalion

• Bicolor• Little shank rot• Attractive ear / husk• Short ears

AP 426

• Bicolor• Best husk cover in trial• Glossy kernels• Good corn taste• 58 day maturity

Anthem XR

• Bicolor• Good husk cover• Attractive husk

Obsession

• Bicolor• Good husk cover• Long ear• Attractive husk• Standard for comparison

in trial

GSS 1170

• Best yellow variety• Short ears

Evaluation of Bt Sweet Corn Lines for Management of Corn Earworm, 2016

Ric Bessin & Nathan Mercer

• Bt sweet corn has been genetically engineered with protein(s) that kill certain caterpillars

• Approved for production since 1998

Corn earwormGenerally found at the ear tip

Types of Bt Sweet Corn• Attribute I

– Cry1Ab gene– Liberty Link trait-

glyfosinate resistance– Syngenta

• Performance Series– Cry1A.105 & Cry2Ab genes– Also have glyphosate

resistance– Monsanto

• Attribute II– Cry1Ab & Vip3A genes– Liberty Link trait-

glyfosinate resistance– Syngenta

Attribute II TripleSweet™

Silking• Volatiles released

from the fresh silks attract female corn earworm moths

• Once silks emerge sprays normally applied on 3-7 day intervals

Moth Catches• Corn earworm moth

populations normally increase as the season progresses.

• This and an increasing temperature cause sprays to be applied more frequently

Corn earworm mothCourtesy Ric Bessin, UK

UK Spindletop Farm Lexington, KY

• Planted June 20, 2016– John Deere

Conservation tillage planter

– Maury silt loam– 4 replications– Plot 4 rows wide

• 33’ X 2.5‘ between rows

Treatments

Bt type or insecticide Variety (se corn)Bt Attribute I WH0809Bt Attribute I BC0805Bt Attribute II AspireWarrior II ProvidenceCoragen ProvidenceUntreated Providence

Coragen and Warrior II applied to center two rows of each treatment at ~3 day intervals during bloom with a CO2 backpack sprayer

Harvest & Evaluation• August 24, 2017• 50 ears harvested

from each treatment• Number of insect

damaged kernels counted

• Number of live corn earworm larvae counted

Results

Sweet corn for wholesale production should have <1% damaged ears.

• Syngenta (2013) notes that growers can decrease insecticide use by 50% with Attribute I varieties.

• Monsanto (2016) indicates that insecticide sprays can be reduced up to 85% with Performance series varieties

• Corn earworms have demonstrated decreased sensitivity to pyrethroidinsecticides in the Midwest and southern US

Questions