ARS | Publication request: GENETIC BASIS OF PARTIAL RESISTANCE TO CROWN RUST IN CULTIVATED OAT 'MN841801-1'

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 17, 2000
Publication Date: N/A

Technical Abstract: Quantitative, or adult-plant, partial resistance to leaf rust pathogens may provide durable protection against rust for cereal crop breeding. The use of molecular maps could facilitate dissection and further introgression of the resistance into new high-performance cultivars. The genetic basis of partial resistance of cultivated oat, Avena sativa L., to crown rust (Puccinia coronata f. sp. avenae) was studied in a population of 158 F6- derived recombinant inbred lines from a cross MN841801-1 (resistant, late) x Noble-2 (susceptible, early). Among 201 RFLP and AFLP loci mapped, 152 were used to establish a framework map of 28 linkage groups spanning 1453 cM (Haldane) at average interval length of 11.7 cM. PLABQTL composite interval mapping (CIM) analysis performed across three field environments detected five partial resistance QTLs. Major QTLs on linkage groups 3 and 26 explained 36.3 and 25.6% of phenotypic variance, respectively; each was also revealed in two-year greenhouse tests. A major QTL for heading date explaining 25.1-36.9% of phenotypic variance, depending on test environment, was linked to the major resistance QTL on linkage group 3. That both resistance and lateness alleles were contributed by MN841801-1 might explain in part the observed association between late heading and resistance to crown rust. The consistency of identification of the rust resistance QTLs across field and greenhouse test environments suggests that the markers linked to them would be useful in marker-assisted breeding of oat for partial resistance to crown rust.