Statewide
In the January 29 Sorghum Tip – Part I, I discussed ‘What does tolerance to the sugarcane aphid mean?’ It is important to have a correct understanding of how these tests were intended to be used, their results—and what the SCA-tolerance results do NOT say. The caution is that we would be mistaken to read too much into the results and assume that preliminary tolerance in controlled settings will indeed translate into field tolerance where environmental conditions are introduced.
I have searched the entire Texas A&M AgriLife Research Crop Testing Program database dating back to 2005 for results on the current commercial hybrids that have been designated by their company as tolerant to SCA. (Pioneer 83P56 is a new release and has not been tested by AgriLife.)
Results are reported for Central & South Texas rainfed, Central & South Texas irrigated, limited data for Northeast Texas rained, as well as Texas High Plains irrigated and dryland. A couple of hybrids have not been tested in several areas of Texas. Because all hybrids were entered by the companies in only a portion of the trials, I can’t directly report the yields. That wouldn’t provide accurate comparisons among these hybrids. Thus the reporting is as follows:
- The number of reported test locations.
- The average percent relative difference in yield vs. the trial average (only for the sites the particular hybrid was entered).
- The average ‘Percentile’ Rank, e.g., this tells how a hybrid compares to all other hybrids; the higher the number the better performing the hybrid’s yield. A hybrid that is in the 80th percentile means it is in the top 20%, or yields better than 80% of the hybrids.
- The actual yield only at the sites where the hybrid was tested. This is important in understanding the hybrids yield and how much chemical control costs for SCA (Transform, Sivanto) are relative to yield and potential revenue. Hybrids in a low-yielding environment would lose more of their revenue to insect control costs. You can’t compare the yields of these hybrid to each other using this number (they represent a different combination of test sites).
South & Central Texas
Rainfed Results^
|
Hybrid |
# of Yield Tests | Avg. % Relative Yield Difference | Avg. Percentile Rank |
Avg. Yield at Test Sites |
|
S.P. KS310 |
Hybrid not tested at any location, 2006-2014 | |||
|
S.P. NK5418 |
Insufficient data (< 3 sites) |
|||
|
S.P. K73-J6 |
3 |
-3.5 % |
35 |
4,333 |
|
S.P. SP6929 |
6 | +0.8 % | 51 |
4,867 |
| Dekalb Pulsar |
Hybrid not tested at any location, 2006-2014 |
|||
| DKS37-07 | 5 | +1.4 % | 50 | 5,561 |
Irrigated Results*
|
Hybrid |
# of Yield Tests | Avg. % Relative Yield Difference | Avg. Percentile Rank | Avg. Yield at Test Sites |
| S.P. KS310 |
Hybrid not tested at any location, 2006-2014. |
|||
|
S.P. NK5418 |
3 | -20.4 % | 13 | 5,772 |
|
S.P. K73-J6 |
6 | -6.2 % | 31 | 6,807 |
| S.P. SP6929 | 9 | -7.8 % | 26 |
6,990 |
| Dekalb Pulsar |
Hybrid not tested at any location, 2006-2014. |
|||
|
DKS37-07 |
Insufficient data (< 3 sites) |
|||
Test sites with 2 or more years:
^Gregory, Danevang, Thrall & Granger
*Weslaco/Monte Alto & Hondo
Northeast Texas
Only three trial sites contained any of these six hybrids. Data from Prosper and Farmsville finds that Sorghum Partners’ NK5418 averaged 5,491 lbs/A, or +3.7% above trial average, and a percentile of 63.
Texas High Plains – Dryland
Rainfed Results
|
Hybrid |
# of Yield
Tests |
Avg. % Relative Yield
Difference |
Avg. Percentile
Rank |
Avg. Yield at
Test Sites |
|
S.P. KS310 |
8 | -17.2 % | 23 | 2,360 |
| S.P. NK5418 | 9 | +12.9 % | 75 |
3,289 |
|
S.P. K73-J6 |
Hybrid not tested at any location, 2006-2014 |
|||
|
S.P. SP6929 |
2 | -3.9 % | 29 |
2,882 |
| Dekalb Pulsar | 8 | +3.6 % | 58 |
2,953 |
|
DKS37-07 |
9 | +6.6 % | 65 |
3,104 |
Texas High Plains – Irrigated
Limited Irrigation Results
|
Hybrid |
# of Yield
Tests |
Avg. % Relative Yield
Difference |
Avg. Percentile
Rank |
Avg. Yield at
Test Sites |
|
S.P. KS310 |
Insufficient data (1 site) | |||
|
S.P. NK5418 |
4 | +6.9 % | 74 |
5,555 |
|
S.P. K73-J6 |
Hybrid not tested at any location, 2006-2014 |
|||
| S.P. SP6929 |
Insufficient data (1 site) |
|||
| Dekalb Pulsar | 2 | -5.6 % | 30 |
4,934 |
|
Dekalb DKS37-07 |
2 | +2.7 % | 59 |
5,289 |
Full Irrigation Results
|
Hybrid |
# of Yield
Tests |
Avg. % Relative
Yield Difference |
Avg. Percentile
Rank |
Avg. Yield at
Test Sites |
|
S.P. KS310 |
No test data | |||
| S.P. NK5418 | 4 | -12.6 % | 17 | 6,595 |
| S.P. K73-J6 |
Hybrid not tested at any location, 2006-2014 |
|||
|
S.P. SP6929 |
No test data | |||
| Dekalb Pulsar |
Insufficient data (1 site) |
|||
| Dekalb DKS37-07 | 4 | -6.5 % | 39 |
6,828 |
Conclusions
Overall, the data for South and Central Texas suggest that the yield trial results of these six hybrids where tested, are average at best in rainfed conditions, and below average in irrigated production. As noted in the previous Sorghum Tip, if any SCA-tolerant hybrid has lower yield relative to trial averages or hybrids you like, you will continue to plant your preferred hybrid. Producers may conclude that {Good yield + SCA control costs – the uncertain risks of SCA} are preferable to a tolerant hybrid with low yield potential; but current hybrids that are designated at SCA-tolerant-based on preliminary greenhouse testing-may not retain field tolerance under field environmental conditions. In spite of this, some producers may elect to include some acres of these hybrids if concerned about SCA. Planting at least some acres of hybrids with early indication of tolerance on your farm—even if 20% of total grain sorghum acreage—can still contribute to your IPM approach on at least some of your acres if the tolerance translates to the field.
As we await observations of field response to these and other hybrids we probably don’t have the needed hybrids with tolerance yet in the commercial market place that will enable us to move forward without dependency on chemical spray control, which is going to curtail grain sorghum acreage.
