Resistance to powdery mildew in one Spanish barley landrace hardly resembles other previously identified wild barley resistances

Abstract

Two major quantitative trait loci (QTLs) associated with resistance to powdery mildew (Blumeria graminis f. sp. hordei) were previously identified on chromosome 7H of the Spanish barley line SBCC097. The two QTLs seemed to share the same chromosomal position as the major genes mlt and Mlf, which were formerly described in Hordeum vulgare ssp. spontaneum-derived lines. In the present work, different lines that carry mlt (RS42-6*O), Mlf (RS137-28*E), or a combination of both (SI-4 and SI-6) were compared with SBCC097 to evaluate their relatedness at the phenotypic, cellular, and genetic levels. The resistance of the lines was characterised by inoculating them with a set of 27 isolates of B. graminis, which displayed a wide range of virulence. It was revealed that SBCC097 possessed a distinctive resistance spectrum. Microscopic assessment of the cytological development of the resistance response showed that SBCC097 clearly formed fewer wellestablished colonies and secondary hyphae than the other lines. This was confirmed by the infection type recorded after visual inspection. Genetic analyses of all five lines, based on markers flanking the QTLs derived from SBCC097 both supported the macroscopic and microscopic data and pointed to the presence of a combination of novel genes or alleles in SBCC097, which may be included in the category of "intermediate-acting" genes, governing resistance mainly at the postpenetration stage.

A Cluster of Nucleotide‐Binding Site–Leucine‐Rich Repeat Genes Resides in a Barley Powdery Mildew Resistance Quantitative Trait Loci on 7HL

“…Such line had two QTL conferring race‐specific resistances on chromosome 7H (Silvar et al, 2010). The mechanism of resistance of this line was classified as consistent with “intermediate‐acting” genes, governing resistance mainly at the postpenetration stage (Silvar et al, 2013a). Genomic approaches allowed the development of new markers to narrow down the QTL intervals (Silvar et al, 2012, 2013b), but were insufficient to definitely locate a manageable physical location or a set of candidate genes for the stronger QTL on 7HL, which is the subject of this work.…”

Significant decrease in yield under future climate conditions: Stability and production of 138 spring barley accessions

“…Nevertheless, introduction of germplasm from exotic accessions can be advantageous in widening the genetic base of crops (Brantestam et al, 2007;Malysheva-Otto et al, 2007;Russell et al, 2000) as traditionally performed in breeding for disease resistance. Here traits have successfully been transferred to elite cultivars to achieve resistance (Colton et al, 2006;Czembor, 2000;Silvar et al, 2013).…”

A novel resistance against powdery mildew found in winter barley cultivars

“…Most European spring barleys carry the mlo gene of non‐specific resistance (Dreiseitl, ), which is fully effective. For breeding winter barley cultivars, an option is pyramiding genes with minor effect (quantitative resistance) (Niks, Xiaoquan, & Marcel, ) derived from cultivars, landraces (Silvar et al, ) and wild barley (Dreiseitl, ). Such a method has proved effective in breeding the resistance to B .…”

“…Directional selection can lead to differences locally and intercontinentally (Dreiseitl, 2014;Jensen, Dreiseitl, Sadiki, & Schoen, 2013;Komínková, Dreiseitl, Malečková, Doležel, & Valárik, 2016) (Dreiseitl, 2017c), which is fully effective. For breeding winter barley cultivars, an option is pyramiding genes with minor effect (quantitative resistance) (Niks, Xiaoquan, & Marcel, 2015) derived from cultivars, landraces (Silvar et al, 2013) and wild barley (Dreiseitl, 2017b). Such a method has proved effective in breeding the resistance to B. graminis f.sp.…”