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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #190953
Title: QTL MAPPING OF RESISTANCE TO GRAY LEAF SPOT IN RYEGRASS: CONSISTENCY OF QTL BETWEEN TWO MAPPING POPULATIONS

Author
item CURLEY, JOE - UNIV OF WISCONSIN
item SIM, S - UNIV OF WISCONSIN
item Warnke, Scott
item Barker, Reed
item Leong, Sally
item JUNG, G - UNIV OF WISCONSIN

Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/2004
Publication Date: 10/31/2004
Citation: Curley, J., Sim, S.C., Warnke, S.E., Barker, R.E., Leong, S.A., Jung, G. 2004. Qtl mapping of resistance to gray leaf spot in ryegrass: consistency of qtl between two mapping populations. American Society of Agronomy Abstracts. Paper No. 5998.

Interpretive Summary: Gray leaf spot (GLS) is a serious fungal disease found on the important turf and forage species, perennial ryegrass that is caused by the rice blast fungus Magnaporthe grisea. Early reports suggest little resistance is present in perennial ryegrass cultivars. However, greenhouse inoculations in our lab using one ryegrass isolate suggests some resistance is segregating in an annual x perennial ryegrass (MFA x MFB) pseudo-F2 population. A well-saturated genetic linkage map was constructed for this population and the segregation seen allowed quantitative trait locus (QTL) analysis. Potential QTL for resistance to one ryegrass isolate was detected on at least three linkage groups. To confirm that QTL detected in the current population are still detected in the next generation, a resistant segregant from the MFA x MFB population, MF8, was crossed with a susceptible perennial clone, L4B-5, from a different genetic background, to form a new pseudo-F2 mapping population segregating for GLS resistance. Understanding the genetic structure from different populations will facilitate development and utilization of more specific selection criteria in perennial ryegrass breeding programs.

Technical Abstract: Gray leaf spot (GLS) is a serious fungal disease on the important turf and forage species, perennial ryegrass (Lolium perenne) caused by the rice blast fungus Magnaporthe grisea. Early reports suggest little resistance is present in perennial ryegrass cultivars. However, greenhouse inoculations in our lab using one ryegrass isolate suggests some resistance is segregating in an annual x perennial ryegrass (MFA x MFB) pseudo-F2 population. A well-saturated genetic linkage map has been constructed for this population using RFLP, RAPD, AFLP, and SSR markers, and the segregation seen allows quantitative trait locus (QTL) analysis in this population. Potential QTL for resistance to one ryegrass isolate, detected on at least three linkage groups, will be discussed. To confirm that QTL detected in the current population are still detected in the next generation, a resistant segregant from the MFA x MFB population, MF8, has been crossed with a susceptible perennial clone, L4B-5, from a different genetic background, to form a new pseudo-F2 mapping population segregating for GLS resistance. The goal of this study is to perform QTL analysis in the new population, to evaluate the consistency of location, number, and effect of QTL for gray leaf spot resistance between these two mapping populations, and ultimately to understand the genetic architecture of this important trait. Such understanding will facilitate its utilization in perennial ryegrass breeding programs.