Breeding for Quality

PLS 664

Spring 2007

End Use Quality - what is it?

SRW Wheat - An ExampleSAMPLE ENTRY MILLING BAKING NO. QUALITYQUALITY

SCORE SCORE * STD = McCORMICK 67.6 C 48.2 E

1401 1 McCormick 67.6 C 48.2 E1402 2 KY00C-2025-01 64.1 C 44.7 E1403 3 KY00C-2025-02 66.3 C 49.5 E1406 7 KY00C-2025-06 73.4 B 56.9 D1414 22 KY00C-2039-03 71.5 B 32.7 F1418 42 KY00C-2053-01 83.2 A 82.9 A1419 43 KY00C-2053-02 75.3 B 72.8 B1420 44 KY00C-2053-03 77.6 B 70.0 B1421 45 KY00C-2053-04 77.7 B 78.8 B1422 47 KY00C-2126-01 62.3 C 55.7 D

Typical Quality Evaluation Scheme

• F4:6 lines from Preliminary Trials - send 100-200 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

Results2005 & 2006 SDS Sedimentation

Source F-Value

Lex05 2006 Lex06 Prn06

Line 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

Results-Regression WM- and Flour- Based Assays

Flour Lactic Acid Retention (%)

70

80

90

100

110

120

130

Wheat Meal SDS Sedimentation Volume (mL)

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Lexington, KY

R2 = .44

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

€

ΔG = Sh2

ΔG = ih 2σ P

Where S = selection differentialand h2 = heritability

Where i = selection intensity

and P = phenotypic standarddeviation

Genetic Progress

€

ΔG = ih 2σ P

Given that h2 and P are parameters ofthe population we are working with, whatcan 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.

Size

40 40

Seln. Intensity 10% 4%

Correlated Traits

• Consider the composite trait T=Y+Q

• Then

• Which means that the total genetic gain consists of both the direct and indirect response to selection for yield and quality.

€

ΔGT = ΔGY + ΔGQ

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

Population Size

Yield

Qua

lity

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?