increasing grain yield and improving bydv tolerance in oat: past, present and future

Increasing grain yield and improving BYDV tolerance in oat:

Past, Present and Future Frederic L. Kolb1 and Jean-Luc Jannink2

1 Dep. of Crop Sci., Univ. of Illinois, 2 USDA-ARS, Cornell Univ.

Outline

• Discuss breeding for increased yield and BYDV tolerance using the Univ. of Illinois program as an example

• Discuss trends in yield and BYDV

tolerance from the UOPN

Outline

• Discuss a snapshot of germplasm exchange in North American oat on the basis of pedigree relatedness analysis

• Initiate discussion of changes to the UOPN to focus germplasm exchange using marker information

• Can oat breeding gains compete with other crops?

Introduction

• Grain yield and BYDV tolerance are important quantitatively inherited traits in oat

• Important breeding objectives

Barley Yellow Dwarf (BYD)

• Most important viral disease of oat

• Causes economically significant yield losses worldwide

• Host plant resistance is the best method for control of BYD

Barley yellow dwarf viruses (BYDVs)

• Five or more species have been described

• Phloem-restricted viruses

• Vectored by aphids

• Wide range of host species

• Symptoms - leaf chlorosis and reddening, stunting, blasting, and reduced root growth

Blasting due to BYDV

Reduced root growth due to BYDV

Trends in BYDV tolerance of breeding lines in Uniform

Nurseries

UEOPN - BYDV Severity Over 40 Years

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

19681970197219741976197819801982198419861988199019921994199619982000200220042006

Year

BYDV Rating (0-9)

Mean Most Tolerant

Top Three Tolerant Linear (Mean)

UMOPN - BYDV Severity Over 40 Years

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

19681970197219741976197819801982198419861988199019921994199619982000200220042006

Year

BYDV Rating (0-9)

Mean Most Tolerant

Top Three Tolerant Linear (Mean)

Progress in BYDV tolerance(1966 – 2007)

• UEOPN ~ 5.4 to 5.0

• UMOPN ~ 6.2 to 4.6

• Best lines tended to be in the 2-3 range

• The average number of IL lines in the top five for BYDV tolerance:

2.5 for UEOPN and 2.2 for UMOPN.

2008 UMOPN Plots – Urbana, IL

Clintland 64 – BYDV susceptible IL98-10145 BYDV tolerant breeding line

University of Illinois procedures for evaluation of BYDV tolerance

• Two or three replications of hills planted with 15 seeds / hill

• Inoculated with aphids carrying BYDV- PAV at Feekes GS 2

• Symptoms rated at Feekes 10.6

• Rating based on chlorosis, stunting, and blasting

• Scale 0 = no symptoms, 9 = severe

Aphid Cultures

Collecting Aphids from cultures

Aphid Dispenser

BYDV Evaluation

Hills

Selection for BYDV Tolerance

• Selection to date has relied on phenotypic evaluation.

• Molecular markers tried but the small number of markers has been a problem.

• The availability of DArT markers and association mapping hold promise for the future.

• Essentially a long-term open recurrent selection breeding program with selection for elite lines embedded within each cycle.

University of Illinois Breeding Procedures

“North American oat breeding is a big recurrent selection program with slow mixing: a communal effort.”

- Brian Rossnagel

• Use modified single seed descent to advance generations rapidly in the greenhouse and cycle new parents into the program quickly.

• Cross (Feb ’08) to selection of panicles from F4 bulks in ~ 18 months (July ’09)

University of Illinois Breeding Procedures

Trends in Yield of Breeding Lines in Uniform Nurseries

UEOPN - Yield Over 42 Years

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

196619681970197219741976197819801982198419861988199019921994199619982000200220042006Year

Bu./Acre

Mean Top Yield

Top Three Yields Linear (Mean)

UMOPN - Yield Over 42 Years

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

1966 1969 1972 1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005Year

Yield (Bu/A)

Mean Top YieldTop Three Yield Linear (Mean)

Average Yields of Uniform Nurseries (1966 – 2007)

• UEOPN ~ 62 bu/A to 118 bu/A = ~ 2222 kg/ha to 4229 kg/ha

- Increase of 1.3 bu/A/yr (48

kg/ha/yr)

• UMOPN ~ 70 bu/A to 119 bu/A = ~ 2509 kg/ha to 4265 kg/ha

- Increase of 1.2 bu/A/yr(43 kg/ha/yr)

Objectives of the Uniform Oat Performance Nurseries

• Test lines for broader adaptation

• Friendly competition! Who’s line will be the best in 2008?

• Identify lines from other programs with potential value as parents in my program

Moving from exchange of genotypes to exchange of “genomic regions”

• Uniform nurseries have provided an important mechanism for oat breeders to exchange genotypes.

• With high density markers and association mapping it may be possible to refine the exchange to introgression of “genomic regions that perform well locally.”

Pedigree Relatedness

• Pedigrees are more difficult to curate than marker data

• => Relatedness in what follows is based on marker data from the new DArT resource

Relatedness between Programs

Saskatchewan and Minnesota

CDC Sol-FiCDC ProFi Sesqui

Leonard

Wabasha& a sib line

Winnipeg and Indiana

Still not completelyunrelated!

Value of “exotic” genomic regions

• Lines from other programs will often be poorly adapted in your target environments

• However, poorly adapted germplasm often carries favorable alleles

– Tanksley, S.D. et al. 1996. Advanced backcross QTL analysis … Theor. Appl. Genet. 92:213-224.

Identification Requirements

• “External genomic regions performing well locally”

• Segregating in the elite UOPN germplasm

• Evaluated locally in your own target environments

• UOPN lines genotyped at high density

Modifications to the UOPN

• In the near future UOPN entries could be genotyped at relatively high density for a modest fee per entry (~ $50 )

• What modifications in the phenotyping and line purification could leverage the most out of this new data?

Can oat breeding gains compete with other crops?

• The short answer – NO.

• Why?

– Resources for research on a species impact the rate of progress.

– Oat is at a huge disadvantage.

• Maize – C4 metabolism and multibillion dollar industry

Summary

• We have made progress!

– Varieties with excellent tolerance to BYDV and enhanced yield potential have been developed.

• New tools including DArT markers, additional SSR markers, and association mapping hold promise for enhancing selection in the future.

Acknowledgments• Quaker Foods and Beverages:

A Division of Pepisco• USDA-ARS• The University of Illinois• USDA-NRI-CSREES

Grant 2007-01682

Personnel:

Norman Smith

Eric Brucker

Who is that in the middle?

Questions?