Page 20-Corn Talk, Lancaster Farming, Saturday. October 14,1995
ALTERNATIVE DESIGNS
FOR HYBRID
STRIP TESTS
Gregory W. Roth
Associate Professor
Agronomy
Penn State
Hybrid strip trials are usually
conducted in one of two
designs. One is a non replicated
strip with individual hybrids
laid out in adjacent strips.
Another method is a tester
design that involves a tester
hybrid to be placed between
every second or third hybrid in
the trial. In this design, hybrid
yields are adjusted based on the
yields of the adjacent tester
strips. Comparisons between
hybrids are then made on the
basis of adjusted yields. The
purpose of this procedure is to
adjust for variation that might
be encountered across the field.
A recent article published in
the July 1992 issue of the Jour
nal of Production Agriculture
by M. A. Schmitt of the Univer
sity of Minnesota and S.J.
Openshaw and M. W. Davis of
Pioneer Hi-bred International
examined, the relative benefits
of the two designs. In the study,
19 large plot yield trials were
conducted in Minnesota using
five hybrids each. The authors
used statistical techniques to
estimate the variation encoun
tered with each design.
The authors found
that in 14 of 19 trials,
the use of the tester
system actually
increased the varia
tion encountered in
the test. In most cases,
the adjustment using
the testers did not
increase the precision
of the test. As a result,
the use of testers to
increase the confi
dence of performance
data is usually unwar
ranted. The authors
suggest that to
increase the precision
of on-farm testing,
instead of going to a
tester system, a sec
ond replication
should be considered.
Replication could
reduce the variation
by one half and could
be accomplished with
little extra work com
pared to the tester
system.
The failure .of the tester sys
tem to adjust yields may be due
to several reasons. First, the
variations in Helds are not
always consistent in one direc
tion. This is obvious to anyone
who has flown over Pennsylva
nia farmland. Secondly,
hybrids may not react the same
way to gradients in productivity
We know that some hybrids are
more sensitive to drought
stress, for example, than others.
And finally, the tester system
spreads the test out over more
land and there is a greater
chance to encounter more
variation.
This study shows that we
should reconsider how we
design hybrid strip trials. Some
good basic rules to follow on
designing strip trials include: 1)
keep the number of entries as
low as possible, 2) replicate if
possible, 3) limit the test to
hybrids of a similar maturity (or
group the hybrids by maturity
in the test) and 4) don’t rely
only, on the results of a single
trial.
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Pennsylvania
Five-Acre
Corn Club
P B Ma *« r . CO i n Gr °*! r * * Mn - • EnrotiM mutt fumiah IN labor to haiv.it,
rtnn Stilt COOp. Extonoion w«gh and prepare tamplM for d«t«rmining
Commorcial Saad Industry moiatura content Theee operations must be
dona in tha praaanca of the official or officials
certifying tha ylalds
What la tha objactlve of tha
Flva Acra Corn Club?
The Pennsylvania Five Acre Corn
Club is a program designed to bring
together com growers, seed dealers,
and extension agents who strive to
achieve more profitable com
production in Pennsylvania.
How la thla accomplished?
Producers enroll in the program
through their county extension
office before July 1. Before com
harvest, they complete a survey of
their production practices and a
farm management exercise. In
1995, this management exercise
will focus on estimating operating
and ownership costs for com
planters.
At harvest, an extension agent or
an approved supervisor will assist
them in performing a yield check
and collect the survey
information. Producers will
receive a summary of yield and
management information from all
participants after the data is
summarized. Top producers will
be recognized at the Pennsylvania
Crops Conference
Serving the Farming Industry for over 30 Years
1188 Enterprise Rd„ East Petersburg, PA 17520
5-Acre Corn Contest
Has Many Benefits
1995
Sponsored by:
What ara aoma of tha kay
rulaa in tha Club?
1 One entry per farm or field An entry fee of
$lO is due* sign-up. (Checks should be
made payable to Penn State University- Corn
Club) A farm operation consists of one or
more forme, managed by one or more farm
operators. A farm operator, whole II or more
years of age by August 1,1H5. is eilgfcte to
enter the Pennsylvania Five-Aore Corn Chib
Fins! report forma should be received at the
Agronomy Department Office. 111ASI
Building, by DtCintMf 1-
2. Size of field Not less than five scree of one
hybrid or variety at one location on the farm
If com ia grown in contour stripe, two or more
strips may be entered, aft stripe entered must
be sampled at harvest time Tote) com
acreage in contour stripe must total not less
than five acres.
3 Hybrid or variety The hybrid or variety must
be commercially available
4 Fields cannot have received any irrigation
5 Harvesting instructions for yield determinations
are outlined on the report form. Harvesting
locations must be selected by the official or
officials checking yields Class 3 requires
harvesting and weighing a minimum of 3 acres
and all harvesting must include the entire length
oftheffekH The harvesting methodology
utilized by National Com Growers Association
Com Yield Contest which involves harvesting
one pass, skipping three passes, harvesting
another pass (or a total of 1 25 acres can be
substituted for the three acre harvest size if
desired. The enroHee must be prepared to have
the field opened to facilitate machine sampling.
Corn Club Banaflta:
• an accurate yield estimate
• learn a useful farm
management technique
• a summary of management
practices of other com growers
• the ability to compete for one of
over 21 awards presented
annually.
What hava w# laarnad in
the paat from tha club?
• v Many growers are using less
than 1 pound of N fertilizer per
bushel of com harvested.
• 40-60% of the participants
sidedress N.
• The average plant population at
harvest on farms in the club is
about 24,000.
• High yields can be produced on
less productive soils, provided
rainfall is timely.
• About 20-25% of com club fields
are cultivated.
• P and K are frequently applied
well above crop removal rates.
7 Samptet for dolormining moioluro content art
to bo plocod m moitturo proof bogt ot timt of
horvott. Tho moitturo percent mutt bo
dotorminod within 24 hourt on ono
dotignatod moitturo tootor for tho county
• Awardtwiß bo made for tho throo highott
yioldt in tho Shotted Grain Horvott Clattoa
and in tho Ear Com Horvott Clattot A
minimum of Itvo ontrtet it roquirod to
ottablith a data with awardt Only ono
data can bo ontorod por farm, or farmt.
undor ono managomont Eligibility for tho
throo yoar avorago data it batod on tho
currant yoar't rotußt plut tho two prowout
yoar'a rotult Ail throo yoar rooultt mutt
havo boon in tho tamo horvott clatt A
Champion wM bo namod for oaeh data batod
on grain yteid por aero A club mombor may
roeoivo only ono award in a given yoar A
throo yoar avorago champion it not oiigfcte to
roeoivo a firat, tocond or third place award in
tho currant yoar, and may not compote for
another throo yoar avorago trophy for throo
yoart. if a porton placet in both throo yoar
and currant yoar dattot, tho award will bo
made in tho throo yoar data
For more information on ruteo or tho Com
Oub, chock with your oxtontion office or
contact Grog Roth at tho Ponn State
Department of Agronomy at 114-M3-1018
lain ad in nmharmcc of Cooperative Extension work
Acu or ConpMi May I md Jana 30. 1914 to
cooperation with the U S Departs en( of Agriculture
and The Pennaylvenia Legislature. L. F Hood. Director
of the Cooperative Extension Service, The Pennsylvania
State University
The Pennsylvania Suu Univeraity in compliance with
federal and atate law* 1a cossmcd to the policy that
alt (Mraorta ahall have equal accau to programs
adsiaaion and csploysent without regard to race
religion, aea national orfgia handicap age or atatua aa
a disabled or Vletnaa era veteran Direct ail
affirmative action inquiries to the Affirmative Action
Office The Pannaylvama State Univeraity 201 Willard
luildmg University Park. PA 1&I02 (114) 163 0471
How do you enroll In the
Five-Acre Corn Club?
Call your county extension office to
check if your county is
participating in the com club
Check the rules on the brochure to
see if you and your field are eligible
to participate. If so, complete the
entry form and send along with
the registration fee of $lO to the
county office. You will receive the
appropriate forms to complete in
August. Finally, make
arrangements with your extension
office for the yield check at harvest.
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