Resistance to barley scald (Rhynchosporium secalis) in the Ethiopian donor lines ‘Steudelli’ and ‘Jet’, analyzed by partial least squares regression and interval mapping uri icon

abstract

  • Results have been analysed using partial least squares regression (PLSR) and interval mapping. In PLSR the major covariance structures or `latent variables' between X (markers) and Y (isolates, tests) are modelled as principal components and their optimal number determined by cross-validation. In `Steudelli' two QTL were detected, one on each of chromosomes 3H and 7H, in 4 out of 5 tests, while in `Jet' only one (different) allele at the 3H locus was found. The validated R-2 varied between 11.0% and 64.9% in the replicated tests with `4004'. With isolate `WRS1872' the 7H locus and another 3H locus were detected. By interval mapping the QTL detected were less stable and generally gave lower R-2 values than PLSR. PLSR does not depend on maps, but interval mapping based on values predicted by PLSR had R-2 around 90%. It is suggested that PLSR may be a useful tool in QTL analysis.
  • The resistance of barley (Hordeum vulgare L.) to Rhynchosporium secalis (scald) has been investigated in two crosses between the susceptible cv. `Ingrid' and two resistant Ethiopian landraces, `Steudelli' and `Jet'. Doubled haploids were inoculated in replicated tests using two isolates of R. secalis, `4004' and `WRS1872'. Expression of resistance differed widely between replicated tests. AFLP, SSR and RFLP markers were used to develop chromosome maps.

publication date

  • 2004
  • 2004