Quantitative Cephalosporium Stripe Disease Resistance Mapped in the Wheat Genome

The soil-borne fungus Cephalosporium gramineum Nisikado and Ikata causes Cephalosporium stripe disease of winter wheat (Triticum aestivum L.), reducing yields significantly in severe cases. There is no known complete resistance to the disease and resistance mapping efforts in wheat have been few. This study was conducted to discover the genomic locations of disease resistance as a preliminary step in the process of molecular marker development. 'Finch' and 'Eltan' progeny were used for quantitative trait loci (QTL) mapping, and a diversity population of 459 individuals was compiled for the first-ever association mapping of resistance to this disease. These populations were genotyped respectively on emergent 9000 (9K) and 90,000 (90K) single nucleotide polymorphism marker platforms and were phenotyped for disease resistance in a 2-yr field study. Twelve resistance QTL were identified in Finch and Eltan, whereas 68 putative QTL were found in the diversity population. Though no QTL of major effect was found, the accumulation of favorable alleles improved resistance, confirming the quantitative nature of Cephalosporium stripe disease resistance. Further investigation will be needed to refine the loci reported here to develop molecular markers to help incorporate and accumulate favorable resistance alleles in new cultivars. Once developed, genetic resistance to Cephalosporium stripe disease will promote economically and environmentally sustainable winter wheat production on C. gramineum- infested soil.