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GrainGenes Reference Report: TAG-92-552

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Reference
TAG-92-552
Title
Genetics of seedling and adult plant resistance to net blotch (Pyrenophora teres f teres) and spot blotch (Cochliobolus sativus) in barley
Journal
Theoretical and Applied Genetics
Year
1996
Volume
92
Pages
552-558
Author
Steffenson B
Hayes P
Kleinhofs A
Abstract
Net blotch (caused by Pyrenophora teres f teres) and spot blotch (Cochliobolus sativus) are important foliar diseases of barley in the midwestern region of the USA To determine the number and chromosomal location of Mendelian and quantitative trait loci (QTL) controlling resistance to these diseases, a doubled haploid population ('Steptoe'/'Morex') was evaluated to the pathogens at the seedling stage in the greenhouse and at the adult plant stage in the field. Alleles at two or three unlinked loci were found to confer resistance to the net blotch pathogen at the seedling stage depending on how progeny exhibiting an intermediate infection response were classified. This result was corroborated in the quantitative analysis of the raw infection response data as 2 major QTL were identified on chromosomes 4 and 6M. A third QTL was also identified on chromosome 6P. Seven QTL were identified for net blotch resistance at the adult plant stage and mapped to chromosomes 1P, 2P, 3P, 3M, 4, 6P, and 7P. The 7 QTL collectively accounted for 67.6% of the phenotypic variance under a multiple QTL model. Resistance to the spot blotch pathogen was conferred by a single gene at the seedling stage. This gene was mapped to the distal region of chromosome 1P on the basis of both qualitative and quantitative data analyses. Two QTL were identified for spot blotch resistance at the adult plant stage: the largest QTL effect mapped to chromosome 5P and the other mapped to chromosome 1P near the seedling resistance locus. Together, the 2 QTL explained 70.1% of the phenotypic variance under a multiple QTL model. On the basis of the chromosomal locations of resistance alleles detected in this. study, it should be feasible to combine high levels of resistance to both P. terres f. terres and C. sativus in barley cultivars.
Probe
dRcs5
QTL
QSb.StMo-1H
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Keyword
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adult-stage
alleles
chromosome
chromosome-maps
cochliobolus-sativus
crop-growth-stage
disease resistance
fungal-diseases
gene-location
gene-mapping
genes
hordeum vulgare
linkage-groups
loci
molecular-mapping
phenotypic-variance
pyrenophora-teres
quantitative genetics
quantitative-traits
seedling-stage
variance