Backcross Segregation Data

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• Principles of Plant Breeding
• Scope of course
• Syllabus
• Textbook and lecture notes
• Exams and grading
• Position paper
• Participation
• Attendance

Horticulture-Agronomy 501
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A
C
B
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• Books and References in Plant Breeding
• Books
• Breeding Field Crops, 4th ed. Poehlman and Sleper
• Principles of Cultivar Development, Fehr
• Principles of Crop Improvement, Simmonds
• Principles of Plant Breeding, Allard
• Journals
• Crop Science
• Journal of the American Society for Horticultural
  Science
• Theoretical and Applied Genetics (TAG)
• Euphytica
• Plant Breeding
• HortScience

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• Assignments and Grading
• Three exams worth 20 each
• Some homework on quantitative aspects of course
• Position paper
• 10 pages maximum, include detailed bibliography,
  required, graded
• Position paper, focus on stating, supporting, and
  defending a plant breeding position 4/18, worth
  15 of final grade

Grading Exam 1(20), Exam 2 (20), Exam 3 (20)
Final (25), Paper (15)
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• Position Paper
• Develop a position (for or against) the position
  outlined
• on the previous slide
• Strongly encouraged to support your position with
• data and with references
• Strongly encouraged to discuss your position with
• classmates and with instructors
• Ten page double-spaced maximum
• Literature citations follow Crop Science
• Include 200 word abstract, title, and name on
  cover page
• DUE APRIL 17
• Discussion / debate on papers later in semester

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• Participation and Attendance
• Both strongly encouraged!
• However, no formal records kept
• If you miss class and want information please
  send email to ilgoldma_at_wisc.edu
• or stop by 327 Plant Science
• email to nienhuis_at_calshp.cals.wisc.edu
• or stop by 377 Plant Science
• If you know in advance you will need to miss an
  exam, please notify us promptly

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You see, sweet maid, we marry a gentler scion to
the wildest stock, and make conceive a bark of
baser kind by bud of nobler race. This is an art
which does mend nature - change it rather - but
the art itself is nature. -Shakespeare The
Winters Tale (1611)
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Not one man in a thousand has accuracy of eye and
judgement sufficient to become an eminent
breeder. If gifted with these qualities, and he
studies his subject for years, and devotes his
lifetime to it with indomitable perseverance, he
will succeed, and may make great improvements if
he wants any of these qualities, he will
assuredly fail. -Charles Darwin, The Origin of
Species (1859)
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Four varieties of wheat which occupied 95.8 of
the Manitoba wheat acreage in 1936 were found on
only 6.7 of the acreage in 1941. Artificially
accelerated evolution pushed them aside. Similar
if less striking changes have taken and are
taking place in all fields of this
continent. Exit Malthus. -K.W. Neatby
(1943)
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Plant Breeding is a Synthetic Field
Structure / Environment
Function / Mechanics
Chemistry Biochemistry Plant Physiology Physics
Plant Anatomy Agriculture Pl.
Pathology Entomology Soil Science
Markets
Information
Calculus Algebra Statistics
Economics
Genetics Cell Biology
Computers
Statistics
Genetics
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Plant Breeding is a Creative Field Forms of
Brassica oleracea
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What Has Plant Breeding Done For Me Lately?

• With gt50 of world food directly from plants,
• Plant breeding has contributed to
• Broad adaptation of crops
• Shifts in land use and availability
• Changing human demographic
• Fiber, structural materials, ornamentals
• Yield gains
• Pest resistance
• Stress resistance
• Increased quality factors

Yield gains in corn and rice increased by 300
since 1940 sorghum, wheat, soybean yield doubled
since 1940 45 Mha Indian land spared since
1960 with improved crops and practices
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Goldman Lecture 1 Graph from
Forrest Troyer, 1996
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Trajectory of Plant Breeding
Domestication Scientific Birth of
Genetics Statisticsl Molecular Biology
Agriculture Hybridization
Brd. Methods
10,000 YA 300 YA
100 YA 70 YA 10 YA

Art and Science
Art and Non-Science Farmers
...... Scientists....
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Ideotype Selection I was observing an artist
carve a dog out of a piece of wood. I asked
him how do you do that? I just carve away
everything that doesnt look like a
dog. Comment from Baxter Black on National
Public Radio, 1/5/99
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...but plant breeding is also about systematic
changes in gene frequency with selection
?G i h2 sp
i selection differential h2 heritability sp
phenotypic standard deviation
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• Basic Principles of Genetic Change in Populations
  over Time
• Fecundity
• Heritable Variation
• Differential Reproduction and Survival

Nature only
Human Influence
Evolution in Nature Evolution under
Domestication
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• Case Studies
• Sinclair, 1998, Crop Science, 38638-643
• Harvest index (HI) is ratio of grain mass to
  total biomass
• HI has increased during modern times
• 80 of wheat yield increase over 120 yr
  associated with HI
• Same story for barley, maize, rice
• Historically, straw production a priority-
  contrast to modern times
• HI change due to partitioning, nitrogen
  accumulation
• Grain N is gt5 fold higher than in straw, so N
  uptake must increase
• Selection for response to N application- green
  revolution
• Selection using HI alone is ineffective

What have plant breeders changed when selecting
for yield?
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• Case Studies
• Abbate et al., 1998, Crop Science, 381203-1209
• Examined grain yield in spring wheat cultivars in
  Argentina
• Recently-released cultivars have higher HI and
  higher yield
• Total biomass has changed little
• Intercepted radiation, growth rate were same for
  all cultivars
• Grain per unit land area was related to
  grain/spike mass ratio
• Changing grain/spike ratio from 71-124 grains per
  gram
• Selection has increased number of grains

What have plant breeders changed when selecting
for yield?
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• Case Studies
• Van Esbroeck et al., 1998, Crop Science, 3833-37
• Low genetic diversity may be a threat
• Coefficient of parentage, r, is probability that
  two alleles are identical by descent
• 17 cotton cultivars account for 97 of acreage
  during 25 years
• r increased from .12-2.0 from 1970-1995
• r 0.07 for 260 released cultivars during same
  period
• Higher r in commonly grown than in released
  cultivars
• Very frequent use of several parents to create
  new cultivars
• Cultivar diversity is no guarantee of field
  diversity

Have breeders changed genetic diversity in
cotton?
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• Case Studies
• Meghji et al, 1984, Crop Sci., 24545-549,
  Duvick, 1977, Maydica 22187-196
• Maize hybrid yield has increased greatly from
  1930s to present
• Better root and stalk quality allow modern
  hybrids to take advantage of higher population
  densities
• Recent inbreds lodge less, stay green longer,
  smaller tassels
• Some 60 of gains due to genetic factors
• Heterosis increased greatly from 1950s to 1970s
• Inbreeding depression showed concomitant increase
• Data suggest dominance plays a primary role

What have plant breeders changed when selecting
for yield?
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• Further Reading and Discussion
• Easterbrook, 1997. Atlantic Monthly. January.
  75-82
• Forgotten Benefactor of Humanity
• Duvick, 1996. Crop Science. 36539-548.
• Plant Breeding, an Evolutionary Concept
• Darwin, 1859. Origin of Species. Chapter 1.
• Darwin, 1868. The Variation of Animals and Plants
  Under Domestication. Chapters 20 and 21.

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