Breeding Switchgrass for Increased Biomass Production

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Breeding Switchgrass for Increased Biomass
Production

• Charles M. Taliaferro
• Roger Fuentes
• Plant Soil Sciences Department
• Oklahoma State University

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Objectives

• Establish a switchgrass breeding program to
  effect sequential long-term improvement in
  biomass yield performance.
• Develop high yielding cultivars for varied
  climatic and edaphic conditions in the south
  central USA.
• Refine breeding procedures to increase
  effectiveness/efficiency.
• Expand the knowledge base on switchgrass breeding
  characteristics and genetic improvement
  potential.
• Collect and characterize germplasm to facilitate
  future progress.

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Available evidence indicates ample heritable
genetic variation for positive response to
selection for biomass yield.
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Narrow-sense Heritability Estimates for Biomass
Yield in Three Switchgrass Populations.
Population Individual plant Half-sib
progeny basis mean basis
------------------- --------------------
SU 95 42 34 NU 95 85 55 SL 93 15 21
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Breeding Strategies

• 1992-96
• Restricted recurrent phenotypic selection in four
  populations
• Developed narrow genetic base synthetic varieties
  with elite plants from breeding populations
• 1997-present
• Phenotypic-genotypic selection
• Development of synthetic varieties including
  2-clone hybrid varieties

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Performance of RRPS Cyclic Populations for
Biomass Yield
Population of C0 Population of C0
SL C1 130 SU C3 116 SL C2 112 SU C2 106 SL
C0 100 SU C1 112 SU C0 100 NL C1 101 NU
C3 119 NL C2 96 NU C2 100 NL C0 100 NU
C1 105 NU C0 100
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Biomass Yields of Lowland Switchgrass
Experimental Synthetics and Standard Cultivars
Test
Cultivar Alamo SL 93-1 93-2 93-3 94-1 Kanlow
NL 93-1 93-2 94-1 LSD
97-4 7.9 6.6 7.8 7.7 6.7 6.8 6.3 6.8
7.7 0.9
97-1 14.3 15.1 13.3 14.6 15.4 14.3 14.6
12.9 15.5 1.7
97-3 12.9 14.2 12.6 13.4 13.4 12.4 1
3.8 11.5 13.4 2.1
98-1 13.9 14.3 13.6 17.5 14.5 12.7 12.6
11.9 13.7 1.6
TX(5-loc) 14.4 16.5 15.8 - 14.8 - 11.
0 - - -
99-1 14.9 19.9 13.3 14.6 15.3 11.8 15.4
14.3 14.5 1.5
------------------------------ Mg ha-1
------------------------------
98-1 Orange, VA 1999-00 99-1 Coffeeville,
MS 2001
97-1 Chickasha, OK 1997-00 97-3 Booneville,
AR 1998-99 97-4 Manhattan, KS 1998-00
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Upland Switchgrass Experimental Synthetics12
Test Environments
Entry Rel. Yld.
Entry Rel. Yld.
Blackwell 100 NU 92-1 121 NU 94-1 117 NU 94-2 119
Caddo 100 SU 92-1 112 SU 94-1 119
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Associated Breeding Research

• Testing effects of yield environment on selection
  response
• Practice GRS on clonal populations grown under
  high and low yield conditions
• Rationale determine if yield environment
  influences selection and ultimately performance
  of cultivars grown under variable yield
  conditions
• Tentative results minimal influence of
  environment on plant selection.

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Associated Breeding Research

• Determining inbreeding effects and potential
  benefits of inbreeding.
• Rationale Selection under inbreeding may
  enhance breeding gains via elimination of
  deleterious genes and fixation of desirable genes
  in homozygous condition.
• Progress 1st inbreeding selection cycle
  completed. S1 plants have variable fertility and
  morphology.

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Associated Breeding Research
Determining heterotic response and potential for
hybrid cultivars.
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Associated Breeding Research

• Collecting and characterizing germplasm.
• Rationale Breeding and genetics research will
  be facilitated by a germplasm collection
  characterized for major descriptors.
• Progress
• 110 accessions evaluated for descriptors.
• Ten groups identified based on cluster analyses.
  
• Isolated intermating blocks established in 2001.

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Associated Breeding Research

• Better define cytogenetic/reproductive
  characteristics.
• Clarify chromosome numbers and ploidy levels.
• Lowlands 4x.
• Uplands mainly 8x, a few 4x and 6x.
• Elucidate polyploid type and mode of inheritance.
• Evidence indicates a diplodized autoploid.
• Establish hybridization potential between
  cytotypes and ecotypes.
• Plants of same ploidy hybridize relatively easily
  regardless of ecotype.
• Plants of different ploidy strongly isolated.

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Summary Conclusions on Breeding

• Ample genetic variation for biomass yield.
• Breeding within the major climatic regions
  required.
• Recurrent breeding procedures can effect
  incremental gains.
• New cultivars with enhanced performance can be
  developed.

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Summary Conclusions on Breeding

• Hybrid cultivars may provide the largest yield
  gains in the near term.
• 1st generation seed from clonally propagated
  parent plants.
• Three-way crosses or double crosses?

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Summary Conclusions on Breeding

• Major limitation
• Reduced efficiency/effectiveness of screen for
  superior genotypes imposed by time and resource
  constraints.
• A selection cycle takes 4 years minimum for our
  GRS procedure when field progeny testing is
  limited to one post-establishment year.
• Land labor resources available for field
  testing are finite.

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Future Needs/Goals to Facilitate Breeding Progress

• More definitive information on selection response
• Measure response to GRS
• Include cyclic RRPS populations
• Better/faster methods of identifying plants with
  highest breeding value
• Marker assisted selection

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Advancing to Commercialization
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BIOMASS ENERGY CONVERSION CENTER

• Oklahoma State University
• University of Oklahoma

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Biomass Energy Conversion Center

• Develop the technology for converting
• low-cost biomass to ethanol

• Feedstock Development
• Biomass Gasification and Syngas Conditioning
• Microbial Catalyst Development
• Syngas Fermentation

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Nine Scientists

• Feedstock development
• R. Huhnke, C. Taliaferro
• Gasification/syngas conditioning
• D. Bellmer, T. Bowser
• Microbial catalyst development
• R. Tanner
• Syngas fermentation
• R. Lewis, A. Johannes
• Economic analysis
• F. Epplin
• Environmental assessment
• B. Barfield

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FEEDSTOCK DEVELOPMENT
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Gasification Process
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Fermentation
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Sources of Initial Support

• Okla. Ag. Expt. Stn.
• V.P. for OSU Research
• Food and Agr. Products Research Center
• College of Engineering, Architecture and
  Technology
• Williams Bio-Energy
• Western Region Biomass Energy Program

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Current Support

• Okla. Agric. Exp. Stn.
• Office V.P. Research
• Williams Bio-Energy
• USDA (CSREES)
• IFAFS
• Federal Initiative with Mississippi State Univ.

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Goal is to develop a pilot plant ASAP and move
the process to commercialization.