Powdery Mildew Resistance Genes in Single-Plant Progenies Derived from Accessions of a Winter Barley Core Collection

Abstract

The main problems of crop gene banks comprise heterogeneity of accessions, resulting from mechanical admixtures or out-crossing during their multiplication, and especially the mislabeling of accessions. These discrepancies can adversely affect the results of many expensive research and breeding projects that are based on the use of gene bank resources. To tackle these problems, 860 single-plant progenies (SPPs) of 172 accessions of the Czech winter barley core collection were grown and tested with a set of 53 isolates representing the global virulence/avirulence diversity of powdery mildew. Seventy-one resistance phenotypes encompassed the diversity of known specific resistances and their combinations. Based on testing groups of five SPPs, 94 accessions had one phenotype found in all five SPPs (homogeneous accessions), whereas in 78 accessions (45.3%) more than one phenotype was identified (heterogeneous accessions). In three varieties, specific resistances against the whole set of isolates were detected, but due to high adaptability of the pathogen, they are not recommended for breeding resistant cultivars. Selected SPPs were integrated in the gene bank and are now a reliable source of genotypically pure seed with defined powdery mildew resistance genes that can be used by breeders and researchers. The results obtained can be used to verify authenticity of accession genotype and pedigree, particularly for older varieties for which no other original criteria are available.

Unlocking the genetic diversity and population structure of the newly introduced two-row spring European HerItage Barley collecTion (ExHIBiT)

“…A small number of the accessions in the collection that were labelled as two-row in their passport data, upon planting were identified as six-row barley. Mislabelling and duplication are the most frequent problems within genebanks, this is due to the large number of accessions maintained ( Mascher et al., 2019 ; Dreiseitl and Nesvadba, 2021 ). Although the 16 six-row accessions were considered as part of the ExHIBiT collection, they were not considered for inclusion in the core collection.…”

“…For instance , the International Barley Core Collection (BCC) was established in 1989 ( van Hintum, 1994 ; van Treuren et al., 2006 ) to reflect the diversity of barley worldwide, and since its inception, it has been used to better understand barley‘s diversity and evolution ( Liu et al., 1999 , 2000 , 2001 , 2002 ). The Spanish Core Collection was assembled to show the diversity of barley found within the Spanish Germplasm Bank ( Igartua et al., 1998 ), and the Czech winter barley collection ( Dreiseitl, 2021 ; Dreiseitl and Nesvadba, 2021 ) has been recently established to screen for disease resistance.…”

Postulation of Specific Disease Resistance Genes in Cereals: A Widely Used Method and Its Detailed Description

“…For tests of accessions in which heterogeneity of resistance was found, samples are individually sown, plant progenies are separately harvested and from each of them (usually five), one segment is tested. In such a case, there are usually 16 pentads on the dishes, i.e., 80 segments, plus four segments of a susceptible control [ 29 ]. When testing wheat with narrower leaves than barley, 26 pentads can be placed on the dish [ 18 ].…”