Bivariate analysis of barley scald resistance with relative maturity reveals a new major QTL on chromosome 3H

Abstract

The disease scald of barley is caused by the pathogen Rhynchosporium commune and can cause up to 30–40% yield loss in susceptible cultivars. In this study, the Australian barley cultivar ‘Yerong’ was demonstrated to have resistance that differed from Turk (Rrs1 (Rh3 type)) based on seedling tests with 11 R. commune isolates. A doubled haploid population with 177 lines derived from a cross between ‘Yerong’ and the susceptible Australian cultivar ‘Franklin’ was used to identify quantitative trait loci (QTL) for scald resistance. A QTL on chromosome 3H was identified with large effect, consistent with a major gene conferring scald resistance at the seedling stage. Under field conditions, a bivariate analysis was used to model scald percentage of infected leaf area and relative maturity, the residuals from the regression were used as our phenotype for QTL analysis. This analysis identified one major QTL on chromosome 3H, which mapped to the same position as the QTL at seedling stage. The identified QTL on 3H is proposed to be different from the Rrs1 on the basis of seedling resistance against different R. commune isolates and physical map position. This study increases the current understanding of scald resistance and identifies genetic material possessing QTLs useful for the marker-assisted selection of scald resistance in barley breeding programs.

Genome-Wide Association Study for Resistance to Rhynchosporium in a Diverse Collection of Spring Barley Germplasm

“…The QTL-7H-1 allele associated with resistance was the minor allele in the collection, with a frequency of 0.22. The QTL-7H-2 is a QTL with the highest P-value and colocalises with QTL mapped in an Australian cultivar [47]. QTL-3H-1, QTL-7H-3, and QTL-7H-4 are also in areas where QTL were previously identified based on bi-parental population studies [10,19,22,[48][49][50][51].…”

“…It is not clear which genes could be putative candidate genes for QTL-7H-1 overlapping with Rrs2 and QTL-7H-4 overlapping with Rrs15 as the genome annotation for these regions does not contain any kinases. QTL-7H-2 overlapping with QTLSR-7H-2017 [47] is likely to contain a quantitative resistance gene that does not have to be a RLK or RLP. While there are only three annotated genes within this interval, none of them represent an obvious candidate for a quantitative resistance gene.…”

Improved breeding forFusarium pseudograminarium(Fusarium crown rot) using qPCR measurement of infection in multi-species winter cereal experiments

“…The linear relationships between each of the four traits was determined from the trait: genotype covariance modelling using methods detailed in Zhang et al (2019) as follows: …”

Wild barley (Hordeum spontaneum) and landraces (Hordeum vulgare) from Turkey contain an abundance of novel Rhynchosporium commune resistance loci

“…The novel loci QRrs-2H.1 and QRrs-4H.2 were identi ed on chromosomes 2H and 4H at positions 567,016,838 (SSM 12_30724) and 27,327,299 (SSM 12_10860), respectively (Table 2). The previously identi ed locus QRrs-3H.2 was also identi ed using the isolate E4 on chromosome 3H at position 493,556,092 (SSM 12_30829), approximately 6.1 Mb distal of qC174_3 (Coulter et al 2019) and 9.9 Mb proximal of QTLSR-3H-2015 (Zhang et al 2019), and embedded within the Qsc_3H_2 locus (Hautsalo et al 2021).…”

“…The locus QRrs-5H.6 was identi ed on chromosome 5H at location 640,002,824 (SSM SCRI_RS_155322) and is within the Qsc_5H_1 locus(Hautsalo et al 2021). The locus QRrs-7H.2 was identi ed on chromosome 7H at position 66,021,760 (SSM 12_30181) located approximately 3.9 Mb proximal to QTLSR-7H-2017(Zhang et al 2019).…”