Patience, Pride, and Prejudice

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Patience, Pride, and Prejudice

• Some Experience with Maize Germplasm
• Tom Hoegemeyer

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Prejudice

• Exotic Maize is too tall, late and not useful in
  my program
• Exotic Maize is hard to work
• Ive tested Exotic Maize in hybrids, and the
  crosses yield less than what I have now
• The native North American races are best suited
  to the conditions I breed for.

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Prejudice

• Usual technique for exotics Inbreed directly in
  the population, select the earliest plants, cross
  the few that work easiest to one tester, throw
  all of them away because they yield less than
  checks.

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Pride

• While there are lots of races and populations of
  maize, God put the best ones here in the US.
• My program (or company, or country, etc.) has
  sorted through the available germplasm, and we
  are working what gives us the best chance to find
  new, better hybrids.

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Pride

• In the US we have done, and are doing the best
  quality and largest quantity of breeding with
  maize, and consequently, the best chance of
  success is working with this domestic material.
• In working exotic germplasm, I would rather start
  with the GEM sources, and select what I want.
  (If it wasnt invented here..)

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Pride

• We have all the performance we need.
• We are more interested in adding biotech traits
  to the great hybrids we already have.
• MAS will be more efficient in germplasm that is
  already adapted.
• Well identify what we need via genomics, and add
  it selectively via MAS.

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Experience

• Most of your observations are correct
• Generally will yield less than current hybrids
• Adaptation problems
• Taller, later, poorer roots
• Significant advantages in health, grain quality
• Will result in fewer hybrids in next five years
  on a per shootbag basis
• Need to be committed to pollinating well into
  August

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Experience

• USGEM testcrosses do have yield
• To test for yield, generally better to test under
  low stress, warmerMay not April planting, dont
  only look at earliest items within a population.
• Look at yield on a relative basis, not an
  absolute basis. Keep the best ones!

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Experience

• In last five years of testing USGEM experiments
  in Nebraska
• Every year, there have been a few entries within
  an LSD of the best checks.
• The lines/populations from the northern-ISU GEM
  are only slightly better adapted than the
  southern-NC State.
• Odds are much better of finding high yields in
  selected S2s than in populations per se.

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Examples

• CHIS775N1912-389-1/LH200 203 14.9
• Pioneer 33P66 210
  17.5
• FS8BS0316-1118-1/LH283 179 15.0
• Pioneer 34B23 195
  14.7
• Best ones still have some adaptation issues
  which impact yield

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Examples

• DK844S1601-997-1-1/TR7322 199 18.9
• DK844S1601-926-1-1/TR7322 185 19.0
• DK888S11-1943-2-1/TR7322 193 20.9
• Hoegemeyer 2679 186 20.7
• Pioneer 33P66 190
  21.0
• With the right testers, some WILL yield

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Patience

• In exotics, especially in populations, you need
  to practice ART of plant breeding.
• Large samples
• Watch for plants that do obvious things well
• Select plants to self, rather than selfing a
  sample, like the earliest 20
• Think about how materials might be used as part
  of future projects

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Other Exotic Material

• (NC368xHX853)F4s/TR7322
• 14 of 89 were statistically equal in yield to
  Pioneer 33B50, 8 were as dry or drier.
• (NC368xHX853lt2)/TR7322
• 4 of 62 were statistically equal in yield to
  Pioneer 33B50, all 4 were as dry or drier.

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Patience Re-cycle

• Most (all?) material, whether exotic inbred or
  GEM selection wont be half a hybrid!
• Cross best exotics with high performing inbreds,
  use large samples!
• Visually select for high heritability traits.
• Use testers with excellent roots/stalks.

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Patience

• Take advantage of work and contributions of
  others
• Inbreds developed from exotics may be more
  immediately useful than popns.
• Iowa State, NC State exotic derived inbreds will
  have better adaptation responses
• Elite inbreds from exotic hybrid programs more
  likely have traits needed for inbreeding here

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Patience

• In longer term, we need to accumulate useful
  variation from the exotic maize populations. GEM
  is an excellent vehicle.
• Think about where to go from here in next 30
  years. New heterotic paterns? New breeding
  popns built from GEM lines? Use genomics and
  MAS to custom build new inbreds from exotics?
  How do we best keep all the parts?
• Thanks for your patience.

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The End