Early Maturing Onion Populations for the Upper Midwestern U.S.

Early Maturing Onion Populations
for the Upper Midwestern U.S.
I.L. Goldman and B. Workmaster

Our Programs
• Onion, carrot, table beet
• Development of inbred
lines, open pollinated
cultivars, and improved
germplasm
• Genetic research
• Over 60 releases
currently in use around
the world

My Jobs
• Professor of Horticulture
and trainer in the Plant
Breeding and Plant
Genetics Program
• Recently stepped down
after 6 years in college
administration
• Co-organizer of the
annual Giant Pumpkin
Regatta

7 years
22 Months

Our Releases
• Inbred lines and OPs
• Sterile and maintainer
pairs
• Released by UW prior to
1996, then by WARF
• Licensed by seed
industry and public
sector partners
WAY lines

Early Onion Project
• Wisconsin growers must
compete with western
growers and the global
marketplace
• Early maturity in latitudes
above 38 degrees would
allow for a longer market
window

Early Onion Project
• Early maturing long day
cultivars for northern
latitudes range from
approximately 90–105 d
• Typical planting occurs
from late April to Early May
• May 1 – August 1 = 93 d
“Ricochet is an early-maturing
(95 day) onion that produces
large-sized bulbs and has high
yield potential”

Early Maturity
• Although early maturing varieties typically have
lower yields…
• A 50 lb. bag could bring $0.50 to $2.00 more in
mid-August than in mid-September, translating
into a 10-20% differential
• Shipping point prices 2007, cents / cwt, USDA
July August September October
16.80 13.70 12.20 10.90

Early Maturity
• Early work at Wisconsin on development of early
maturing onions took place in the 1950s
• Crosses between long x short day types to
produce cultivars like ‘Early Harvest’
Early Harvest - Breeder: USDA. Parentage: B2108A x TEG951C
Early Yellow Globe inbred by Texas Early Grano. Characteristics: F1
hybrid, small plant size, semi-glossy foliage; bulb size intermediate,
light yellow color, globe, mild, soft; very early maturity.
Adaptation: all sections except southern United States. Hybrid Early
Harvest, USDA release 1 Dec. 1953.
Vegetable Cultivar Descriptions for North America Onion (A-L), Lists 1-26 Combined Edited by Michael J. Havey

Early Maturity
• Since 1995, we have been
selecting onion
populations for early
maturity
• We have developed five
synthetic populations
that show promise as
early maturing
germplasm
Early Onion Synthetics
mature by late July

Our Approach
Bulb Production Seed Production Synthetic
HS Families
Combines synthetic
population
development with recurrent
selection

WEOS
• The WEOS project began with evaluation of OP
cultivars that showed promise for earliness
• Included Imai Early Yellow, Early Cream Gold,
Australian Cream Gold, M&R Early, Hustler,
Northstar, Trapp’s Downing, RNX-10081, Pukekohe
Longkeeper Early
• Also included six accessions from the USDA-NPGS
collection including PI 43345, PI 264650
• Inbred lines from the Wisconsin program including
W446, W434 and USDA Inbred B2264

• Bulbs harvested and
intercrossed in cages to
form five separate
synthetic populations
• Individual inbred lines, OP
selections, and PI
selections crossed with
one or more synthetic
populations

• An example might be
{(PI264650 x W420) x
Early Onion Synthetic 1}
• Multiple crosses were
placed in each cage
• Seed from each half-sib
family was sown the
following year and
evaluated for maturity
• Obvious hybrids were
selected and recombined
Cages at Seminis
in DeForest, WI

Population Number of Cycles Number of Families
WEOS 1 7 15
WEOS 2 6 10
WEOS 3 6 17
WEOS 4 5 1
WEOS 5 4 1

WEOS
• During 2009 and 2010, we compared each population
in on-farm trials with 6 commercial varieties that had
maturities from 90-120 days
• Plots were four rows, three replications per year
• Thinned to 3.8 cm spacing between plants in early
June
• Check cultivars were Northstar, Sherman, Trailblazer,
Fortress, Nicolet, and Sedona. Nebula and Ricochet
were also used in 2010

EOS 2 and EOS 3 show
early maturity

EOS 5, EOS 1, and EOS 4
show relative earliness

Population On August 5, 2009 On July 29, 2010
WEOS 1 17% 32%
WEOS 2 57% 49%
WEOS 3 67% 47%
WEOS 4 17% 16%
WEOS 5 37% 26%
Early check cultivar mean: 12% 22%
Mid check cultivar mean: 5% 11%

% tops down
100
90
80
70
60
50
40
30
20
10
0
1 wk
7/20 7/27 8/3 8/10 8/17
EOS#1 bulked
EOS#2 bulked
EOS#3 bulked
EOS#4 bulked
EOS#5 bulked
Early cv #1
Early cv #2
Mid cv #1
Mid cv #2
Late cv #1
Late cv #2

Outcome
• We have recombined sources of
earliness in long day onion into
five synthetic populations
• We have recurrently selected
these populations for early
maturity in Wisconsin
environments
• We believe they may be a
source of earliness for other
long day onion breeding
programs

Release
• These are not finished lines or
cultivars
• Rather, it is our intent to make
these populations available as
germplasm for breeding
• Released through Wisconsin
Alumni Research Foundation
• The manager of this germplasm
is Emily Bauer, emily@warf.org

Acknowledgements
And Scott Hendricks of Seminis Vegetable Seeds

https://mywebspace.wisc.edu/groups/Goldman/Web