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This article in CS

  1. Vol. 47 No. 1, p. 174-179
    Received: June 22, 2006

    * Corresponding author(s): pmiklas@pars.ars.usda.gov
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QTL Analysis of ICA Bunsi-Derived Resistance to White Mold in a Pinto × Navy Bean Cross

  1. Phillip N. Miklas *a,
  2. Karen M. Larsena,
  3. Karolyn A. Terpstrab,
  4. Darrin C. Haufc,
  5. Kenneth F. Graftond and
  6. James D. Kellyb
  1. a USDA-ARS, Vegetable and Forage Crops Research Unit, 24106 N. Bunn Rd., Prosser, WA 99350
    b Dep. of Crop and Soil Sciences, Michigan State Univ., East Lansing, MI 48824
    c Pioneer Hi-Bred International, Inc., 7250 NW 62nd Ave, Johnston, IA 50131
    d Dep. of Plant Sciences, North Dakota State Univ., Fargo, ND 58105


Breeding for genetic resistance to white mold [Sclerotinia sclerotiorum (Lib.) de Bary] in dry bean (Phaseolus vulgaris L.) is difficult because of low heritability. To facilitate breeding, researchers have sought to identify QTL underpinning genetic resistance to white mold. We identified two QTL conditioning ICA Bunsi-derived resistance to white mold in a pinto × navy bean (Aztec/ND88–106–04) recombinant inbred line (85 RILs) population. ND88–106–04 is a navy breeding line with resistance to white mold derived from ICA Bunsi navy. Aztec pinto is susceptible. The QTL were located to linkage groups B2 and B3 of the core map. The B2 QTL expressed in three of four field environments explaining 24.7, 9.0, and 8.7% of the phenotypic variation for disease severity score. The B3 QTL expressed in two of four environments, explaining 15.7 and 5.3% of the phenotypic variation. The B2 QTL was identified previously in ICA Bunsi × navy and ICA Bunsi × black bean RIL populations. The resistance conferred by the B2 QTL has a physiological basis due to association with stay green stem trait and lack of association with disease avoidance traits. The B3 QTL, undetected in previous studies, was associated with disease avoidance traits (canopy porosity, plant height), stay green stem trait, and maturity. The B2 QTL with stable expression in multiple environments and across genetic backgrounds will be most amenable to manipulation by breeders.

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