Introgression of White Mold Resistance From the Secondary Gene Pool

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Introgression of White Mold Resistance From the
Secondary Gene Pool of Common Bean


Henry Terán-Santofimio
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Outline

• ? Importance of Dry Bean
• ? Dry Bean White Mold
• ? Objectives
• ? Breeding Strategy
• ? Greenhouse and Field Screening
• ? Results
• ? Future studies

APS Diseases of Legumes
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Importance of dry bean

• According to 2002 census, there were 1,691,775
  acres of dry bean planted in the U.S.
• Idaho ranked 6th after ND, MI, NE, MN, and CO.
• Among all counties in the U.S., Twin Falls ranked
  3rd.
• 60 of beans grown in Idaho belong to the market
  class Pinto

http//www.nass.usda.gov/id
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Main goals of breeding programs

• Seed yield
• Quality of seed
• End use and cooking
  traits
• Wide adaptation
• Resistance to diseases
• Fungal (Rust, Anthracnose, White mold, etc.)
• Bacterial (CBB, HBB, etc.)
• Viral (BCMV, BGMV, Curly Top)

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Dry Bean White Mold

? Devastating disease across the USA in cool
humid regions ? Caused by Sclerotinia
sclerotiorum ? Wide host range of 400 species ?
Fungus is endemic ? Seed transmitted ? Yield
loss 40, 90

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Courtesy H. Schwartz, CSU
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Dry Bean White Mold

• ? Inadequate resistance to white mold
• ? Low levels in dry bean, high levels in
  secondary gene pool
• ? Two mechanisms of resistance
• ? Avoidance Upright architecture and
  open canopy
• ? Physiological Quantitatively inherited
• ? 12 Qtls
• ? Small effects

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White Mold Resistance in Pinto Cultivars Released
from 1944 to 1999.



YR Year of Release
Rating scale, 1No WM symptoms and 9severely
diseased
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Why Slow Improvement of Resistance?

1. Low Heritability h2 0.01-0.67 2. Large
Environmental Influence 3. Inadequate Screening
Methods 4. Inadequate Breeding Methods 5. Low
Level of Resistance in Dry Beans

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Research Objectives

• Introgress white mold resistance genes from the
  secondary gene pool using crosses between ICA
  Pijao with P. coccineus, P. costaricensis, and P.
  polyanthus.
• Compare the level of resistance obtained with
  known resistant sources of white mold.

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Gene Pools (GP) of Phaseolus cultivated species
P. coccineus P. costarricensis
P. lunatus
GP4
GP1
GP2
GP3
Phaseolus vulgaris Wild and cultivated
P. Polyanthus
P. acutifolius
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Phaseolus Species in the Secondary Gene Pool
P. coccineus
P. polyanthus
P. costaricensis
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Breeding Strategy

1. Introgression of Genes from the Secondary Gene
Pool ? P. coccineus G35171, G35172 ?
P.costaricensis S33720 ? P. polyanthus
G35877 2. Reliable Screening Methodology 3.
Greenhouse and Field Evaluation

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G35171
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G35172
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Source CIAT-URG
G35877
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S33720
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Ica Pijao
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Development of Interspecific Breeding Lines


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Making Crosses
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Problems of interspecific crosses

• Rapid return to Phaseolus. vulgaris
• Distorted segregation
• Sterility
• Instability of expression of white mold
  resistance
• Presence of highly deleterious genes
• Delayed maturity

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P. vulgaris x P. coccineus
F3
F2
F2
F4
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Greenhouse screening
Temperature 80F-85F/60F-65F Photoperiod
11 hd/13hn Relative humidity 95-100
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Greenhouse screening Inoculum

Use fresh (
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Resistant (1-3)


Susceptible (7-9)
Intermediate (4-6)
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Greenhouse screening 423 IBL

• Fort Collins, Colorado from 2002-2006 straw
  test, using 6 pots, 2 plants/pot.
• Kimberly, Idaho from 2004-2006 Petiole and cut
  branch test, 3 pots, 2 plants/pot.
• Selection of plants with intermediate and
  resistant reaction.
• Complete randomized block design in Colorado (12
  plants) and Idaho (6 plants), 2006. (2 replicates)

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Field screening in Idaho
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Field screening, Idaho

• Fields (Kimberly-Parma) were heavily fertilized
  with nitrogen.
• Sclerotias were broadcast in the fields in late
  fall or early spring.
• The nursery was inoculated at the beginning-,
  mid- and late flowering stage with ascospores
  (2003), ascosporesmycelial (2004) and mycelial
  (2005-06).
• Plots were irrigated weekly by gravity
  irrigation.

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Sprinkler irrigation system
R. Henson 2005
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Field screening, Idaho

• 2002-2003 single rows, 3.5 m long, spaced 0.56m
• 2004-2005 4 rows of 3.5 m, 2 replications.
• 2006 4 rows of 3.5 m, 3 replications.
• Randomized complete block design.
• Reaction to white mold was recorded using a 1
• to 9 scale, where
• 9 severely diseased or dead plants.
• 1 no visible symptoms on stems and pods.

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Results

Sequential white mold screening

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Results

Mean white mold score of selected IBL
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Comparison with known resistant sources

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Small seed upright architecture late maturity,
but different flower and seed coat color
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Summary

• First successful introgression of white mold
  resistance from P. costaricensis and P.
  polyanthus into common bean.
• Three of five IBL were developed using the
  congruity backcross method between ICA Pijao and
  P. coccineus.
• The use of congruity backcrosses to introgress
  white mold resistance from related species
  resulted in the most resistance phenotypes
  compared to other types of crosses.

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Future Studies

• Determine the effectiveness of IBL for
  controlling WM without chemicals and management
  practices across different environments.
• Study the inheritance with molecular mapping of
  WM resistance in these IBL.
• Transfer the highest levels of introgressed WM
  resistance into pinto and great northern bean
  cultivars for Idaho bean producers.

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Acknowledgments

• This research was funded by the USDA Sclerotinia
• Initiative since 2002.
• Dr. S. Singh, University of Idaho
• Dr. B. Zemetra, Univesity of idaho
• Dr. C. Mohan, Univesity of idaho
• Dr. H. Schwartz, Colorado State University
• Dr. P. Miklas USDA-ARS-Prosser, Washington
• Dr. M. Lema, visiting scientist, Spain
• R. Hayes, manager, Kimberly RE Center
• C. Robinson, manager, Parma RE Center
• Julia Piaskowski, and Karen Laitala

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Questions?