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2-Plants: Bt-cotton in Ohio did not pay off for farmers



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TITLE:  Evaluation of Bt-Corn and Non-Bt Isolines in Ohio
SOURCE: Crop Observation and Recommendation Network, USA
        C.O.R.N. 99-33, by Hal Willson
        http://www.ag.ohio-state.edu/~corn/archive/1999/dec99/99
        -33.html
DATE:   January 10, 1999

----------------- archive: http://www.gene.ch/ ------------------


" ... benefit derived from an investment in Bt-Corn may not be
warranted under Ohio growing conditions."

For more critical informations on Bt-corn see:
http://www.btinternet.com/~nlpwessex/Documents/gmagric.htm

                          *****


Evaluation of Bt-Corn and Non-Bt Isolines in Ohio

During the past three years, trials including multiple hybrids of
Bt-corn and comparable isolines have been conducted at the
Western and Northwestern Branch Stations. The goal of this trial
is to evaluate yield benefits that may be attributed to the use
of corn that has been genetically modified to prevent losses due
to annual infestations of European corn borer (ECB). Results of
trials conducted during the 1999 growing season are presented in
Table 1.


Table 1 - Comparison of Bt-Corn Hybrids and Non-Bt Isolines at
the Western and Northwestern Branch Stations, 1999. 

================================================================
Treatment    Properties  Stand per   ECB Obs.   Plant   Yield
                         100 Row Ft  /Cavities  Larvea  Bu./Ac.
================================================================

Western Branch Station, Clark County
Asgrow 730   Non-Bt       98.50 b      0.20      0.20    145.9
Asgrow 730Bt Yieldgard    93.75 b      0.00      0.00    137.6
DeKalb 647   Non-Bt      105.75 ab     0.70      0.55    156.2
DeKalb 647Bt Yieldgard    98.25 b      0.00      0.00    137.6
Garst 8481   Non-Bt       93.75 b      0.75      0.55    133.4
Garst 8481Bt Starlink    116.75 a      0.00      0.00    144.8

----------------------------------------------------------------

Northwestern Branch Station, Wood County
Asgrow RX601 Non-Bt      130.9 a       1.10      0.75    166.0
Asgrow RX601YG Yieldgard 131.3 a       0.00      0.00    163.7
DeKalb 595   Non-Bt      128.4 ab      0.90      0.60    171.7
DeKalb 595Bt Yieldgard   124.1 b       0.00      0.06    161.3
Garst 8481   Non-Bt      128.8 a       1.25      0.95    168.7
Garst 8481Bt Starlink    128.3 ab      0.00      0.00    163.6

================================================================

Means in a column followed by the same letter are not
significantly different, P = 0.05.

- Bt-corn hybrid suppressed ECB injury to minimal levels.
  However, ECB infestations observed in non-Bt corn isolines at
  both the Western and Northwestern Branch Station trials were
  marginal in regard to causing economic losses. 

- At the Western Branch, stand loss due to cutworm infestation
  was prevented by the Garst 8481 Bt hybrid, which includes the
  Starlink trait. This is the first case of significant
  prevention of a natural infestation of black cutworm injury
  documented in a Ohio replicated field trial (and possibly
  within the mid-west region). 

- Differences in yield observed between Bt-corn hybrids and non
  Bt corn isolines evaluated were not significant. 

A summary of results observed in three years of field evaluations
of Bt-corn hybrids and equivalent non-Bt isolines conducted at
both the Western and Northwestern Branch stations is presented in
Table 2. 


Table 2 - Evaluation of Stand, Corn Borer Infestation and Yield
of Bt-Corn Hybrids and Non-Bt Isolines at two OARDC Research
Stations from 1997 to 1999. 

=================================================================
Year of Trial  No. Hybrids  Stand per    ECB Obs.  Plant   Yield
               Evaluated    100 Row Ft.  Per       Larvae  Bu/A
                                         Cavaties
=================================================================

Western Branch Station, Clark County
    1997        4 Bt-Corn     137.7       0.15      0.01   156.5
                4 Isolines    135.6       0.91      0.26   152.2
    1998        3 Bt-Corn     136.1       0.02      0.00   131.5
                3 Isolines    130.0       0.15      0.11   130.2
    1999        3 Bt-Corn     102.9       0.00      0.00   140.0
                3 Isolines    99.3        0.55      0.43   145.2
................................................................
 3 Yr. Avg.       Bt-Corn     125.6       0.06      0.00   142.7
                  Isolines    121.6       0.54      0.27   144.5

----------------------------------------------------------------

Northwestern Branch Station, Wood County
    1997        4 Bt-Corn     116.4       0.20      0.08   176.1
                4 Isolines    114.7       1.66      0.45   175.5
    1998        3 Bt-Corn     123.5       0.00      0.00   174.9
                3 Isolines    114.5       0.07      0.12   163.8
    1999        3 Bt-Corn     127.9       0.00      0.02   162.9
                3 Isolines    129.4       1.08      0.77   168.8
................................................................
 3 Yr. Avg.       Bt-Corn     122.6       0.07      0.03   171.3
                  Isolines    119.5       0.94      0.45   169.4
================================================================


- The bottom line of the results presented in the preceding table
  is that the corn yields of Bt-Corn hybrids and their non-Bt
  isolines evaluated at two locations in Ohio over a three year
  time period are equal. 

- Exceptions may exist, but the results demonstrate that corn
  borer impact over time on Ohio corn is not significant and that
  the benefit derived from an investment in Bt-Corn may not be
  warranted under Ohio growing conditions.


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