Breeding for Quality
PLS 664
Spring 2007
End Use Quality - what is it?
SRW Wheat - An Example
SAMPLE
NO.
*
1401
1402
1403
1406
1414
1418
1419
1420
1421
1422
ENTRY
STD =McCORMICK
1 McCormick
2 KY00C-2025-01
3 KY00C-2025-02
7 KY00C-2025-06
22 KY00C-2039-03
42 KY00C-2053-01
43 KY00C-2053-02
44 KY00C-2053-03
45 KY00C-2053-04
47 KY00C-2126-01
MILLING BAKING
QUALITY QUALITY
SCORE SCORE
67.6 C 48.2 E
67.6 C 48.2 E
64.1 C 44.7 E
66.3 C 49.5 E
73.4 B 56.9 D
71.5 B 32.7 F
83.2 A 82.9 A
75.3 B 72.8 B
77.6 B 70.0 B
77.7 B 78.8 B
62.3 C 55.7 D
Typical Quality Evaluation
Scheme
• F4:6 lines from Preliminary Trials - send 100200 g to USDA Quality Lab for micro tests
• F4:7 lines - same
• F8:9 lines - send to quality lab for larger
scale milling/baking tests
• F8:10 lines - variety release candidates are
entered in wheat quality council trials
In-House Quality Tests
• Quality analysis based on wheat meal
rather than flour
• Able to produce with inexpensive
grinder
• Measure overall soft wheat quality
• Predict gluten strength
In-House Quality Tests
•
•
•
•
Why do these tests?
Possible added value for grower
Extra $$ in grower’s pocket
Identify lines that you might otherwise
discard
• Identify lines that may be good parents
Wheat Meal SDS
Sedimentation Volume
Results
2005 & 2006 SDS Sedimentation
Source
F-Value
Lex05
2006
Lex06
Prn06
7.50***
3.00***
4.33***
2.62***
Loc*Line
n/a
1.58***
n/a
n/a
CV
n/a
15.51
11.86
19.40
HBS2
HR2
n/a
0.67
0.41
0.77
0.62
Line
Results-Regression
WM- and Flour- Based Assays
130
Lexington, KY
R2 = .44
Flour Lactic Acid Retention (%)
120
110
100
90
80
70
4
5
6
7
8
9
10
11
12
13
14
Wheat Meal SDS Sedimentation Volume (mL)
15
16
17
18
Genetic Progress over Time
• Was found that progress in winter wheat
over time was much greater than in
spring wheat
• Can attribute this difference to very
strict quality requirements of spring
wheat varieties
• Canadian spring wheats show the least
progress
Recommended malting
barleys
• Growers are encouraged to contact their local elevator, grain handler or
processor to gauge market demand for any variety grown in their
region prior to seeding. 2006 crop plantings by variety are included at
the end of this announcement.
• Changes from 2006: The two-rows, CDC Copeland, Conrad, and Craft
have been added to the list.
• Recommended Six-Row Malting Barley Varieties
• Variety Year* Variety Year*
• Drummond 2002 Robust 1984
• Excel 1990 Stander 1995
• Foster 1997 Stellar-ND 2006
• Lacey 2000 Tradition 2004
• Legacy 2001
HRW Quality: Decline over
Time?
• Cox et al., 1989
• Perception and grumbling among
bakers mainly, that “quality isn’t what it
used to be”
• “Old Timer” study conducted
• 40 HRW wheats released over 70 years
evaluated for quality traits
HRW Quality
• Regression coefficients show:
– Flour protein increased more rapidly in
recent years
– Quality index increased more rapidly in
recent years
– Flour yield varied according to environment
HRW Quality
• Regression coefficients show:
– Quality index increased more rapidly over
time than did grain yield (p.630, paragraph
2)
– This was in contrast to the conventional
wisdom of millers and bakers that quality
had declined because breeders were
selecting only for yield
HRW Quality
• “This parallel improvement is not a
contradiction of the general crop breeding
axiom that yield and quality, especially as
indicated by protein concentration, are
negatively related. If breeders had selected
for only yield or only for quality, it is likely that
either trait could have been improved more
rapidly. But they selected for both and
improved both.”
Genetic Progress
G  Sh
2
Where S = selection differential
and h2 = heritability
G  ih  P
2
Where i = selection intensity
and P = phenotypic standard
deviation
Genetic Progress
G  ih  P
2
Given that h2 and P are parameters of
the population we are working with, what
can we do to increase progress?
We must increase selection intensity.
Increasing Selection Intensity
Family Seln.
Mass Seln.
Popn. Size
200
1000
No. Selected
20
40
Effective Popn. 40
Size
Seln. Intensity 10%
40
4%
Correlated Traits
• Consider the composite trait T=Y+Q
• Then GT  GY  GQ
• Which means that the total genetic gain
consists
of both the direct and indirect

response to selection for yield and
quality.
Direct and Indirect Response
• It is intuitively reasonable that if we are
dealing with two “must have” traits like
yield and quality, then we do NOT want
to limit genetic variation for either trait
• Therefore we must evaluate bigger
populations
Quality
Population Size
Yield
Farmers vs. End Users
• Farmers - want premiums
• End users - think in terms of discounts
• Where is the happy medium
Farmers vs. End Users
• Industry benefits from cooperation
• Advantages of contract growing
• Identity preserved system
Scab Resistance - A Quality
Trait
• Millers call it their top quality trait
• Will they pay for it?
• Will farmers give up some yield for it?