Patience, Pride, and Patience, Pride, and PrejudicePrejudice

Some Experience with Maize Some Experience with Maize GermplasmGermplasm

Tom HoegemeyerTom Hoegemeyer

PrejudicePrejudice

• Exotic Maize is too tall, late and not useful Exotic Maize is too tall, late and not useful in my programin my program

• Exotic Maize is hard to work Exotic Maize is hard to work • I’ve tested Exotic Maize in hybrids, and the I’ve tested Exotic Maize in hybrids, and the

crosses yield less than what I have nowcrosses yield less than what I have now• The native North American races are best The native North American races are best

suited to the conditions I breed for.suited to the conditions I breed for.

PrejudicePrejudice

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

PridePride

• While there are lots of races and While there are lots of races and populations of maize, God put the best populations of maize, God put the best ones here in the US.ones here in the US.

• My program (or company, or country, etc.) My program (or company, or country, etc.) has sorted through the available has sorted through the available germplasm, and we are working what germplasm, and we are working what gives us the best chance to find new, gives us the best chance to find new, better hybrids.better hybrids.

PridePride• In the US we have done, and are doing In the US we have done, and are doing

the best quality and largest quantity of the best quality and largest quantity of breeding with maize, and consequently, breeding with maize, and consequently, the best chance of success is working with the best chance of success is working with this domestic material.this domestic material.

• In working exotic germplasm, I would In working exotic germplasm, I would rather start with the GEM sources, and rather start with the GEM sources, and select what I want. (If it wasn’t invented select what I want. (If it wasn’t invented here…..)here…..)

PridePride

• We have all the performance we need.We have all the performance we need.• We are more interested in adding biotech We are more interested in adding biotech

traits to the great hybrids we already have.traits to the great hybrids we already have.• MAS will be more efficient in germplasm MAS will be more efficient in germplasm

that is already adapted.that is already adapted.• We’ll identify what we need via genomics, We’ll identify what we need via genomics,

and add it selectively via MAS.and add it selectively via MAS.

ExperienceExperience

• Most of your observations are correct:Most of your observations are correct:– Generally will yield less than current hybridsGenerally will yield less than current hybrids– Adaptation problemsAdaptation problems– Taller, later, poorer rootsTaller, later, poorer roots– Significant advantages in health, grain qualitySignificant advantages in health, grain quality– Will result in fewer hybrids in next five years Will result in fewer hybrids in next five years

on a per shootbag basison a per shootbag basis– Need to be committed to pollinating well into Need to be committed to pollinating well into

AugustAugust

ExperienceExperience

• USGEM testcrosses do have yieldUSGEM testcrosses do have yield• To test for yield, generally better to test To test for yield, generally better to test

under low stress, warmer—May not April under low stress, warmer—May not April planting, don’t only look at earliest items planting, don’t only look at earliest items within a population.within a population.

• Look at yield on a relative basis, not an Look at yield on a relative basis, not an absolute basis. Keep the best ones!absolute basis. Keep the best ones!

ExperienceExperience

• In last five years of testing USGEM In last five years of testing USGEM experiments in Nebraska:experiments in Nebraska:– Every year, there have been a few entries Every year, there have been a few entries

within an LSD of the best checks.within an LSD of the best checks.– The lines/populations from the “northern-ISU” The lines/populations from the “northern-ISU”

GEM are only slightly better adapted than the GEM are only slightly better adapted than the “southern-NC State”. “southern-NC State”.

– Odds are much better of finding high yields in Odds are much better of finding high yields in selected S2’s than in populations per se.selected S2’s than in populations per se.

ExamplesExamples

CHIS775:N1912-389-1/LH200CHIS775:N1912-389-1/LH200 203 14.9 203 14.9Pioneer 33P66Pioneer 33P66 210 17.5 210 17.5

FS8B:S0316-1118-1/LH283FS8B:S0316-1118-1/LH283 179 15.0 179 15.0Pioneer 34B23Pioneer 34B23 195 14.7 195 14.7

Best ones still have some adaptation issues Best ones still have some adaptation issues which impact yield which impact yield

ExamplesExamples

• DK844:S1601-997-1-1/TR7322 199 18.9DK844:S1601-997-1-1/TR7322 199 18.9• DK844:S1601-926-1-1/TR7322 185 19.0DK844:S1601-926-1-1/TR7322 185 19.0• DK888:S11-1943-2-1/TR7322 193 20.9DK888:S11-1943-2-1/TR7322 193 20.9

• Hoegemeyer 2679Hoegemeyer 2679 186 20.7 186 20.7• Pioneer 33P66 190 21.0Pioneer 33P66 190 21.0

• With the right testers, some WILL yieldWith the right testers, some WILL yield

PatiencePatience

• In exotics, especially in populations, you In exotics, especially in populations, you need to practice ART of plant breeding.need to practice ART of plant breeding.– Large samplesLarge samples– Watch for plants that do obvious things wellWatch for plants that do obvious things well– Select plants to self, rather than selfing a Select plants to self, rather than selfing a

sample, like the earliest 20%sample, like the earliest 20%– Think about how materials might be used as Think about how materials might be used as

part of future projectspart of future projects

Other Exotic MaterialOther Exotic Material

• (NC368xHX853)F4’s/TR7322(NC368xHX853)F4’s/TR7322– 14 of 89 were statistically equal in yield to 14 of 89 were statistically equal in yield to

Pioneer 33B50, 8 were as dry or drier. Pioneer 33B50, 8 were as dry or drier.

• (NC368xHX853<2)/TR7322(NC368xHX853<2)/TR7322– 4 of 62 were statistically equal in yield to 4 of 62 were statistically equal in yield to

Pioneer 33B50, all 4 were as dry or drier.Pioneer 33B50, all 4 were as dry or drier.

Patience: Re-cyclePatience: Re-cycle

• Most (all?) material, whether exotic inbred Most (all?) material, whether exotic inbred or GEM selection won’t be half a hybrid!or GEM selection won’t be half a hybrid!

• Cross best exotics with high performing Cross best exotics with high performing inbreds, use large samples!inbreds, use large samples!

• Visually select for high heritability traits.Visually select for high heritability traits.• Use testers with excellent roots/stalks.Use testers with excellent roots/stalks.

PatiencePatience

• Take advantage of work and contributions Take advantage of work and contributions of othersof others

• Inbreds developed from exotics may be Inbreds developed from exotics may be more immediately useful than pop’ns.more immediately useful than pop’ns.– Iowa State, NC State exotic derived inbreds Iowa State, NC State exotic derived inbreds

will have better adaptation responseswill have better adaptation responses– Elite inbreds from exotic hybrid programs Elite inbreds from exotic hybrid programs

more likely have traits needed for inbreeding more likely have traits needed for inbreeding herehere

PatiencePatience

• In longer term, we need to accumulate useful In longer term, we need to accumulate useful variation from the exotic maize populations. variation from the exotic maize populations. GEM is an excellent vehicle.GEM is an excellent vehicle.

• Think about where to go from here in next 30 Think about where to go from here in next 30 years. New heterotic paterns? New breeding years. New heterotic paterns? New breeding pop’ns built from GEM lines? Use genomics and pop’ns built from GEM lines? Use genomics and MAS to custom build new inbreds from exotics? MAS to custom build new inbreds from exotics? How do we best keep all the “parts”?How do we best keep all the “parts”?

• Thanks for your patience.Thanks for your patience.

The EndThe End