Development of near-isogenic lines for a major QTL on 3BL conferring Fusarium crown rot resistance in hexaploid wheat
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By essentially fixing the genetic background, near-isogenic lines (NILs) are ideal for studies of the function of specific loci. We report in this paper the development of NILs for a major QTL located on the long arm of chromosome 3B conferring Fusarium crown rot (FCR) resistance in hexaploid wheat. These NILs were generated based on the method of the heterogeneous inbred family analysis. 13 heterozygous lines were initially selected from three segregating populations using a single SSR marker linked with the major FCR QTL. The two isolines for each of the putative NILs obtained showed no obvious morphological differences, but differences among the NIL pairs were large. Significant differences in FCR resistance between the isolines were detected for nine of the 13 putative NIL pairs. The presence of the FCR allele from the resistant parent reduced FCR severity by 29.3–63.9% with an average of 45.2% across these NILs. These NILs will be invaluable in further characterising this major FCR locus, in studying the mechanism of FCR resistance and in investigating possible interactions between FCR resistance and other traits of agronomic importance.
KeywordsFusarium crown rot Near-isogenic lines Disease resistance Quantitative trait loci Wheat
The authors are grateful to Dr John Manners for his critical reading of the manuscript. JM is also grateful to the University of Western Australia for financial support through an International Postgraduate Research Scholarship and the University Postgraduate Awards.
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