Resistance to Scald (Rhynchosporium secalis) in Barley (Hordeum vulgare) Studied by Near-Isogenic Lines: I. Markers and Differential Isolates

Abstract

Near-isogenic lines (NILs) with resistance for scald in seventh generation backcross with 'Ingrid' as recurrent parent (RP) were tested with seven differential isolates of Rhynchosporium secalis in Norway and Canada. NILs of 'Turk', 'Brier', 'CI 8162', 'La Mesita', 'Hispont', 'Atlas 46', 'Modoc', 'Hudson', 'Abyssinian', 'Steudelli', and 'CI 2222' also were evaluated for field reactions. The genetic characterization of the NILs (degree of isogeneity with Ingrid) and with each other was carried out. The molecular marker pattern shows that the backcrossing program has resulted in from 86.3 to 100% RP genome in the NILs, depending on the marker system. On an average, 96% RP genome was found in the NILs. There were certain consistent (pairwise) differences between the NILs and RP on chromosomes 3H and 7H. Both chromosomes are known to contain loci conferring resistance to R. secalis, indicating successful introgression from the donors into the NILs. Approximately two-thirds of the observed RP-NIL polymorphisms were linked to the assumed resistance in the NIL. Based on the marker and phenotypic analyses of the NILs, suggestions for a more appropriate and updated terminology of genes for resistance to R. secalis in barley are made. The proposed changes in nomenclature also indicate the differentials that are available as NILs and those lacking.

Combination of seedling and adult plant resistance to leaf scald for stable resistance in barley

“…Rrs1 is a complex locus on the long arm of chromosome 3H with multiple alleles (Graner and Tekauz 1996;Bjornstad et al 2002Bjornstad et al , 2004. Other genes include Rrs13 on chromosome 6H (Abbott et al 1995;Genger et al 2003b), Rrs2, Rrs12 and Rrs15 on chromosome 7H (Abbott et al 1992;Genger et al 2003aGenger et al , b, 2005Schweizer et al 1995), Rrs14 on chromosome 1HS (Garvin et al 1997(Garvin et al , 2000 and Rrs16 on chromosome 4HS (Pickering et al 2006).…”

Genetic mapping of resistance to Rhynchosporium commune and characterisation of early infection in a winter barley mapping population

“…These are predominantly located on chromosomes 2, 3 and 7H (Zhan et al 2008). Several of these resistance loci (effective against rhynchosporium) have been identified in cultivated barley varieties such as Rrs1 alleles in Brier, Turk, and La Mesita (Bjornstad et al 2002). Wider germplasm collections have also been used for the identification of novel resistances such as Rrs13 from Hordeum sponteneum (Abbott et al 1992).…”

Pathogen Populations Evolve to Greater Race Complexity in Agricultural Systems – Evidence from Analysis of Rhynchosporium secalis Virulence Data

“…Race-specific interaction follows the ‘gene-for-gene’ model [21]. Incompatible interactions occur between barley major resistance genes [22], [23] and their corresponding R. secalis avirulence alleles, resulting in a resistant phenotype. Resistant genotype in this case does not necessarily indicate a lack of pathogen invasion and colonization [20].…”