Stand Establishment in Early Sweet Corn

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Stand Establishment in Early Sweet Corn

• Mark A. Bennett, Elaine M. Grassbaugh and Robert
  J. Precheur
• The Ohio State University
• Dept of Horticulture Crop Science

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• Pre-1961 sugary1 (su1) allele with higher WSPs
• 1961 first supersweet cvs (sh2) released
  (Illini Xtra Sweet)
• 1970s sugary enhanced (se1) developed
• Today su1, sh2, se1 and at least 5 other genes
  used singly or in combination
• (Marshall Tracy, 2003)

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Supersweets

• Genetics Based on shrunken 2 (sh2) gene
• - Homozygous (no variation at sh2 gene)
• - Therefore product should be uniform
• General characteristics
• - High sugar 25-30
• - Low in phytoglycogen may lack corn flavor
• - Originally perceived tough, now some quite
  tender
• - Crispy or crunchy texture due to high water
  content
• - Should be planted in warmer soils gt60oF

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Supersweets (continued)

• - Loses sugar very slowly, increased shelf life
  and harvest period, but will
  lose moisture and quality as time passes
• - Excellent for long distance shipping
• Crossing restrictions
• - Must cross with homozygous sh2
• (B. Tracy, WI)

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Sugary (standard)

• Genetics based on the sugary1 (su1) gene
• - Homozygous (no variation at the su1 gene)
• - Therefore, product should be uniform
• General characteristics
• - Low sugar 5-15
• - High in phytoglycogen (25)
• - Tough to tender creamy texture
• - Can be planted in cool soils

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Sugary standard (continued)

• - Loses sugar very rapidly, 50 in one day at
  room temp. Short shelf life and harvest
  period
• - Today mainly for processing
• (B. Tracy, WI)

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Sugary Enhancer (se, EH, TableSweets)

• Genetics based on the sugary1 and the se1 genes
• - Homozygous (no variation at su1 or se1
  gene)
• - Therefore product should be uniform
• General characteristics
• - Middle sugar 15-25
• - High in phytoglycogen (25)
• - Usually tender to very tender very creamy
  texture

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Sugary enhancer (continued)

• - Soils gt55oF
• - Loses sugar rapidly, 50 in one day at
  room temp. Short shelf life and harvest
  period
• - Excellent for local fresh market, roadside
  trade
• Crossing restrictions
• - Must cross with homozygous su1
• (B. Tracy, WI)

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Improved quality sh2 Augmented, Xtra Tendertm,
Gourmet Sweettm Multisweetstm

• Genetics somewhat unclear
• - Based on the sh2 gene
• - Homozygous sh2 (no variation at the sh2
  gene)
• - A few may have su1 segregating
• - Most should be uniform

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Improved quality sh2 (continued)

• General characteristics
• - High sugar gt30
• - Excellent corn flavor very tender
• - Needs warmer soils gt60oF
• - Hold quality for a long period of time
• - Fr. mkt., may compete with sugary enhancer
• Crossing restrictions
• - Must cross with homozygous sh2
• (B. Tracy, WI)

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Cultivars based on Sugary1. Triplesweettm,
Sweet-Breedtm, hetero Se Synergistics (most)

• Genetics Based on sugary1 (su1) gene and
  combinations of other genes
• - Homozygous at su1
• - Other genes will be heterozygous kernels on
  one ear will have different genotypes (like
  bicolor)
• General characteristics
• - increased sugar in some kernels and some
  kernels will be high in phytoglycogen (variable
  kernels on one ear)

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Sugary 1 (continued)

• General Characteristics
• - Increased sugar in some kernels some high in
  phytoglycogen
• - Generally good tenderness
• - Can be planted in cooler soils gt50-55oF
• - Some kernels will lose sugar and moisture
  rapidly
• Crossing restrictions
• -Must cross with hybrids based on su1
• (B. Tracy, WI)

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Sweet Breeds

• Cvs Sugar Ace, Sweet Symphony, Sweet Ice from
  HM
• Probably crosses between su1su1 se1se1 and
  su1su1 sh2sh2
• So kernels you plant would be su1su1 Se1se1
  Sh2sh2
• Kernels would look like and germinate like
  traditional sugary corn

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Sweet Breeds (continued)

• However, after pollination in the field
• - 56 of the kernels would be traditional
  sugary
• - 19 would be sugary enhanced
• - 25 would be supersweet
• Like Triplesweets the kernels on the ear will be
  variable
• ( B. Tracy, WI)

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Synergistics

• Most are homozygous sugary1 and segregate for
  another mutant
• If sugary based on the ears you sell, 75 of the
  kernels will be standard sugary1 and 25 either
  se or sh2
• Advantage plant sugary kernels with good
  germination
• Disadvantage non-uniform product with 75 of
  the kernels relatively low quality

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Summary

• sugary1 group shrunken2 group
• Standard Supersweet, Xtra Sweet
• Sugary enhanced Augmented
• Sweet Breedstm Multisweetstm
• Table Sweetstm Xtra Tendertm
• Triple Sweetstm Gourmet Sweettm
• Synergistics (most)
• (B. Tracy, WI)

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Sweet Corn Seed Trts 2003

• Fremont-- standHillsboro
• How Sweet It Is July Gold sh2 se
  sh2 se
• UTC 32 47 12 12
• CTA 62 74 26 38
• CTAImaz 75 70 28 36
• CTATopsin 76 81 33 50
• CTAFlint 69 70 37 38
• CTAPoncho 67 72 44 58
• LSD (0.05) 8.5 10.4 13.2 15.5

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Sweet corn seed trts (continued)

• Fremont-- stand--Hillsboro
• sh2 se sh2 se
• CruMaxApr 73 74 32 36
• A13Apr 75 75 40 37
• MaxApr 69 67 28 26
• A13Apr 74 70 36 42
• MaxAprCGA 74 72 36 34
• MaxAprDiv 75 71 35 31
• LSD (0.05) 8.5 10.4 13.2 15.5

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Sweet corn seed trts. and cold test

• - germ- vigor ranking
• sh2 se sh2 se
• UTC 73 48 8 11
• CTA 77 74 7 4
• CTAImaz 79 83 5 3
• CTATopsin 77 73 3 1
• CTAFlint 79 77 4 5
• CTAPoncho 81 67 1 2
• LSD (0.05) NS 8.1 - -

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Sweet corn seed trts and cold test

• -- germ-- vigor ranking
• sh2 se sh2 se
• CruMaxApr 71 63 6 8
• A13Apr 73 59 2 9
• MaxApr 68 56 6 10
• A13Apr 73 73 3 5
• MaxAprCGA 75 71 4 7
• MaxAprDiv 82 76 1 6
• LSD (0.05) NS 8.1 - -

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ISCDA means (17 locations)

• ------- stand--------
• How Sweet It Is July Gold
• sh2 se
• UTC 26.3 25.6
• CTA 50.3 50.6
• CTAImaz 53.7 53.8
• CTATopsin 60.0 58.6
• CTAFlint 56.5 57.0
• CTAPoncho 56.4 56.7

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ISCDA means (17 locations)

• -- germ--
• How Sweet It Is July Gold
• sh2 se
• CruMaxApr 56.7 54.3
• A13Apr 57.2 55.1
• MaxApr 54.7 51.4
• A13Apr 54.5 55.0
• MaxAprCGA 58.2 55.3
• MaxAprDiv 56.2 55.2

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Thermogradient table results (Bi-color sh2)

• 12-16C (57-61F)
• Cv. 3D 5D 7D 10D
• 272A 0 0 0 7
• 277A 0 0 0 3.3
• Mirai 301BC 0 5 10 23.3
• ACX 725BC 0 8.3 8.3 20
• ACX 1012BC 0 0 5 20
• Tango 0 0 5 12
• BSS 9686 0 2 6.6 22

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Thermogradient table results (Bi-color sh2)

• 18-20C (64-68F)
• Cv. 3D 5D 7D 10D
• 272A 0 35 53 70
• 277A 3.3 15 12 34
• Mirai 301BC 12 38 65 82
• ACX 725BC 10 30 42 63
• ACX 1012BC 0 52 73 80
• Tango 6 13 43 52
• BSS 9686 10 65 74 87

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Thermogradient table results (Bi-color sh2)

• 22-30C (gt72F)
• Cv. 3D 5D 7D 10D
• 272A 71 83 87 89
• 277A 39 81 85 89
• Mirai 301BC 63 83 87 88
• ACX 725BC 60 87 90 95
• ACX 1012BC 81 91 93 95
• Tango 63 85 91 92
• BSS 9686 93 98 99 99

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Thermogradient table results (Bi-color se)

• 12-16C (57-61F)
• Cv. 3D 5D 7D 10D
• Chippewa 0 2 8.3 12
• Navajo 0 2 7 12
• Luscious 0 15 17 27
• Bojangles 0 3.3 8.4 32
• Ambrosia 0 7 15 18
• Brocade 0 5 22 38
• HMX0351BES 0 0 6.6 43

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Thermogradient table results (Bi-color se)

• 18-20C (64-68F)
• Cv. 3D 5D 7D 10D
• Chippewa 5 57 75 92
• Navajo 0 27 53 77
• Luscious 3.3 50 75 90
• Bojangles 2 38 73 82
• Ambrosia 12 63 94 95
• Brocade 7 63 80 90
• HMX0351BES 5 40 62 85

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Thermogradient table results (Bi-color se)

• 22-30C (gt72)
• Cv. 3D 5D 7D 10D
• Chippewa 73 92 93 93
• Navajo 39 79 91 95
• Luscious 75 93 98 99
• Bojangles 71 98 95 97
• Ambrosia 71 92 99 99
• Brocade 70 81 93 94
• HMX0351BES 61 95 98 99

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