Sorghum Tips

Sugarcane Aphid “Tolerant” Grain Sorghum Hybrids: Part II – Commercial Hybrid Yields

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.