Molecular breeding for the BaMMV/BaYMV resistance gene ym4 in winter barley

Abstract

The aim of this investigation was to develop a procedure for the largescale molecular breeding for ym4, allowing resistance to BaMMV/BaYMV to be fixed in early breeding generations of winter barley. A codominant STS marker derived from the restriction fragment length polymorphism marker MWG838 for the ym4 resistance gene was combined with a new and easy procedure for preparing leaf samples for polymerase chain reaction (PCR), theoretically allowing one person to extract DNA from 5000 samples in a single day. In the procedure for molecular breeding for ym4, all steps, including leaf sampling, DNA extraction, PCR amplification and digestion with restriction enzyme were assembled in microtitre plates allowing multipipetting throughout the procedure, including the loading of gels. The method is amenable to further automation with the aid of a robot arm. Double haploid (DH) lines, as well as F2 and F4 breeding lines were analysed and, based on markers, homozygous and heterozygous BaMMV/BaYMVresistant plants were identified for further breeding. The winter barley breeding programmes were modified to include marker-based selection for BaMMV/BaYMV resistance on DH or on F2 individuals, which had been preselected for mildew and leaf rust resistance.

Molecular markers and doubled haploids in European plant breeding programmes

“…Direct selection of genotypes removes environmental influence when assaying for the presence of desired traits. Selection of BYMV resistance in winter barley with the help of molecular markers Tuvesson et al 1998) and BYDV in spring and winter barley (Ford et al 1998;Paltridge et al 1998) are examples of how a molecular marker approach may replace the classical screen for resistance in the field. Furthermore, by combining molecular markers and DHs it is possible to stack resistance genes on top of each other, so called pyramiding such as demonstrated by Werner et al (2005) and now used by breeders.…”

Potential of SSR markers for plant breeding and variety identification in Australian barley germplasm

“…This will maintain/increase the reputation of barley exporters. It is practicable to screen batches of 100 seeds for the detection of contaminating genotypes at a level as low as 1%, by analysing SSR markers utilising DNA isolated from shoots or seeds using high-throughput DNA extraction methods (Wang et al 1993;Steiner et al 1995;Clancy et al 1996;Tuvesson et al 1998;Saini et al 1999).…”

Automation of DNA marker analysis for molecular breeding in crops: practical experience of a plant breeding company

“…First, marker‐assisted selection (MAS) can both improve selection and the efficiency of field trials by replacing complex and sensitive selection tests, e.g. barley yellow mosaic virus (Tuvesson et al. 1998), phoma in Brassica (Foisset et al.…”

“…phoma in Brassica (Foisset et al. 1998); barley yellow mosaic virus (Tuvesson et al. 1998); (b) e.g.…”