Identification and QTL mapping of resistance to Turnip yellows virus (TuYV) in oilseed rape, Brassica napus

Dieter Hackenberg, Elvis Asare-Bediako, Adam Baker, Peter Walley, Carol Jenner, Shannon Greer, Lawrence Bramham, Jacqueline Batley, David Edwards, Regine Delourme, Guy Barker, Graham Teakle & John Walsh

Theoretical and Applied Genetics volume 133, pages 383–393(2020)

Key message

Partially dominant resistance to Turnip yellows virus associated with one major QTL was identified in the natural allotetraploid oilseed rape cultivar Yudal.

Abstract

Turnip yellows virus (TuYV) is transmitted by the peach-potato aphid (Myzus persicae) and causes severe yield losses in commercial oilseed rape crops (Brassica napus). There is currently only one genetic resource for resistance to TuYV available in brassica, which was identified in the re-synthesised B. napus line ‘R54’. In our study, 27 mostly homozygous B. napus accessions, either doubled-haploid (DH) or inbred lines, representing a diverse subset of the B. napus genepool, were screened for TuYV resistance/susceptibility. Partial resistance to TuYV was identified in the Korean spring oilseed rape, B. napus variety Yudal, whilst the dwarf French winter oilseed rape line Darmor-bzh was susceptible. QTL mapping using the established Darmor-bzh × Yudal DH mapping population (DYDH) revealed one major QTL explaining 36% and 18% of the phenotypic variation in two independent experiments. A DYDH line was crossed to Yudal, and reciprocal backcross (BC₁) populations from the F₁ with either the susceptible or resistant parent revealed the dominant inheritance of the TuYV resistance. The QTL on ChrA04 was verified in the segregating BC₁ population. A second minor QTL on ChrC05 was identified in one of the two DYDH experiments, and it was not observed in the BC₁ population. The TuYV resistance QTL in ‘R54’ is within the QTL interval on Chr A04 of Yudal; however, the markers co-segregating with the ‘R54’ resistance are not conserved in Yudal, suggesting an independent origin of the TuYV resistances. This is the first report of the QTL mapping of TuYV resistance in natural B. napus.

See https://link.springer.com/article/10.1007/s00122-019-03469-z

Figure 4: Genetic linkage maps of ChrA04 from DYDH and BC₁ experiments and physical position of Turnip yellows virus (TuYV) resistance QTL on ChrA04 using the Brassica rapa genome assembly GCA_000309985.2 v3.0