About Us | Help Videos | Contact Us | Subscriptions



This article in CS

  1. Vol. 43 No. 6, p. 2234-2239
    Received: Nov 28, 2002

    * Corresponding author(s): Patrick.M.Hayes@orst.edu
Request Permissions


Pyramiding and Validation of Quantitative Trait Locus (QTL) Alleles Determining Resistance to Barley Stripe Rust

  1. Ariel J. Castroa,
  2. Xianming Chenb,
  3. Ann Coreyc,
  4. Tanya Filichkinac,
  5. Patrick M. Hayes *c,
  6. Christopher Mundtd,
  7. Kelley Richardsonc,
  8. Sergio Sandoval-Islase and
  9. Hugo Vivarf
  1. a Departamento de Producción Vegetal, Est. Exp. “Dr. Mario A. Cassinoni”, Facultad de Agronomía, Universidad de la República, Ruta 3 Km.373, Paysandú 60000, Uruguay
    b U.S. Department of Agriculture, Agricultural Research Service, Washington State University, Pullman, WA 99164-6430, USA
    c Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331-3002, USA
    d Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
    e Instituto de Fitosanidad, Colegio de Postgraduados, Chapingo, Mexico
    f ICARDA/CIMMYT, Apdo. 6-641, 06600 Mexico, DF, Mexico


The use of molecular and quantitative trait locus (QTL) analysis tools initially lent support to the idea that relatively few genetic factors were the principal determinants of complex traits, including quantitative resistance (QR) to plant diseases. However, there are concerns regarding bias in QTL estimation and reproducibility of QTL effects in different genetic backgrounds. We are interested in mapping determinants of QR, and pyramiding resistance alleles at QTL loci may lead to durable resistance as well as provide independent validation of QTL effects and estimation of QTL interactions. We used molecular marker information to validate effects of resistance alleles at three QTL conferring QR to barley stripe rust (caused by Puccinia striiformis West. f. sp. hordei). Two of the QTL [one on chromosome 4(4H) and one on chromosome 7(5H)] trace to one parent, while another QTL on chromosome 5(1H) traces to a different parent. The pyramids of these QR alleles provide independent estimates of QTL effects, influence of genetic background on QTL effects, QTL × QTL interaction, and QTL × environment interaction. Our results validate QTL effect estimates, showing that a small number of QTL explained 94% of the genetic variation in trait expression in a new genetic background. Original QTL estimates were quantitatively biased, but that did not preclude the achievement of selection responses. We also confirmed the additive effects of the QTL alleles, as well as the consistent effects of QTL alleles across environments.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © 2003. Crop Science Society of AmericaCrop Science Society of America