Title:
Exploring Mo17 maize in a way that explains today’s genetics
Author:
Larry Morris, Jr.1,2*; Carolyn Lawrence1,4; and Candice Gardner1,3.
1. Iowa State University, Ames, IA 50011; 2. University of New Mexico, Albuquerque, NM
87102; 3. USDA-ARS, PIRU, Ames, IA 50011; 4. USDA-ARS, CICGRU, Ames, IA 50011.
ABSTRACT
Maize is the most abundant crop produced worldwide. Maize (corn) is an amazing plant
that contributes to society in many ways. For example, corn contributes to the bio-fuels that
serve as an alternative fuel for vehicles, corn and corn syrup are used in many snacks we
eat, and corn is used as feed for livestock. There are several major endosperm types of
maize, including flint, floury, dent, sweet and popcorn. Breeders have the responsibility of
providing corn for the world. Because the genome of a particular line designated Missouri
17 (Mo17) is currently being sequenced, its derivation is the focus of this work. Reviewed
here is brief history of the evolution of maize and the lineage of Mo17.
Introduction:
Evolution Era
During the early 1900’s breeders started to inbreed maize. Gregor Mendel studied
inheritance and developed principles that collectively led to the science of genetics and the
scientific fundamentals used by today’s plant breeders (1979). Soon after (1904), Dr. G.H.
Shull and Dr. Edward East started to inbreed maize and found an important aspect. Shull
developed a single cross hybrid of two inbred parent maize lines. What Shull noticed about
this particular cross is its enhanced performance over open pollinated maize or either
inbred parent; hybrid productivity exceeded that of open pollinated varieties. Dr. Donald F.
Jones (1918) found out more about the functioning of hybrid crossing. The earliest inbred
lines were very unproductive, and produced very few seeds (progeny). It was difficult to
maintain the parent lines. In order to obtain large numbers of hybrid progeny, he created
the double cross, (a subsequent cross between two single crosses). Hybrid breeding was the
basis for developing modern commercial corn and can be given the major credit for maize
becoming the number one crop in the world. Mo17 was created and became one of the most
used parents for producing maize hybrids in America.
Materials and Methods:

Books and Articles were gathered from personal communication and Interviews.
Books used with this research are: Second Edition Specialty Corns by Arnel Hallauer,
Breeding Field Crops Second Edition by John Milton Poehlman, and Compilation of
North America Maize Breeding Germplasm by J.T Gerdes, C.F. Behr, J.G. Coors and
W.F. Tracy from the University of Wisconsin-Madison.


Personal communication:
1.) Marty Sachs
2.) Mike Lee
3.) Carolyn Lawrence
4.) Candice Gardner
Interviews:
1.) Arnel Hallauer
Results and Discussion:
The following is a tree of lineage and background of Mo17.
The top half is the pedigree of Mo17. All but one of Mo17’s parents is from the Non Stiff
Stalk (NSS)type of germplasm. Highlighted by a blue outline, Reid Yellow Dent is the only
parent that is derived from a type of maize germplasm called Stiff Stalk (SS).
These classes
of germplasm are representative of different heterotic patterns. When parents of different
heterotic patterns are crossed, their progeny is better performing than either parent; this
phenomenon is called heterosis.
The bottom half explains where the different types of Mo17 germplasm used in our study
originated; because versions were shared among various researchers at different times
during their development, it is possible that genetic differences developed over time. The
source of Mo17 that was used for sequencing can be traced back from Dr. Hake’s lab, to Dr.
A. Hallauer who got it from its original developer, Dr. M. Zuber (highlighted green). When
Zuber gave Hallauer germplasm, Zuber was not completely finished developing Mo17, and
later versions were distributed to other researchers. From there, Hallauer passed the
germplasm to Mike Lee’s and Hake’s lab. Dr. Lawrence, with the help of Dr. Hallauer, Mark
Millard, Dr. Hake, Dr. Marty Sachs, and others traced the distribution history of Hake’s
source and found out that the Mo17 germplasm was received from Zuber at various times in
development. This could have important implications, as researchers need to understand
whether or not they are using the exact same genetic maize materials in order to compare
and interpret their findings. With the sequencing finished, experiments were run to
compare the sequenced Mo17 source with other Mo17 sources from other labs by collecting
other types of phenotypic and genotypic information. Comparisons are to be made between
the different Mo17 germplasm sources.
Figure 1: Derivation of Mo17 and Origin of Various Sources
Gordon Hopkins X Little Yellow Corn
Reid Yellow Dent
Gold mine
Stiff Stalk Parent
A USDA corn mixed with other varieties
Krug (landraces)
Lancaster Surecrop (from Noah Hershey)
Ci.I 187-2 (Female) X C103 (Male)
Mo17 (Dr. Zuber Stock)
A.Hallauer
C. Martin
Mike Lee
Ed Coe
L. Darrah
Goodman/Buckler
IBM Ri Parent
Hake’s Lab
Conclusion:
In conclusion, after genetically analyzing Mo17 in hake’s lab, examples from the original
sources of Zuber stock was gathered so it could be compare to one another. We found them
to be similar which is good because researchers can know that the source of Mo17
germplasm used will not affect the interpretation of results. Here is a good example of the
impact to better understand where maize comes from and how new endeavors contributed.
As a result of those endeavors explored during the evolution era, genetic sequencing now
not only provides the ability for us to compare and trace lineages, but it may eventually help
us understand heterosis between different maize populations.
Reference:
Jugenheimer, Robert. Corn Improvement, Seed Production, and Uses. Canada: John Wiley &
Sons, Inc., 1976.
Kiesselbach, T.A. The Structure and Reproduction of Corn. Cold Spring Harbor, New York:
Cold Spring Harbor Laboratory Press, 1999.
Poehlman, John. Breeding Field Crops Second Edition. Westport, Connecticut: AVI Publishing
Company, INC., 1979.
Troyer, Arnel R. Hallauer. Second Edition Specialty Corns. Library of Congress Card Number
00-039767: CRC Press LLC, 2001.
Gerdes, Behr, Coors, W.F. Tracy. Compilation of North America Maize Breeding Germplasm.
Madison, Wisconsin: Crop Science Society of America, Inc., 1993.
Acknowledgement:
Exploring Mo17 maize in a way that
explains today’s genetics
By: Larry Morris Jr.
GWC Internship
Summer 2009