Inheritance of scald resistance from barley lines 4176/10/n/3/2/6 and 145L2

Singh, A. K., Rossnagel B. G., Scoles, G. J. and Pickering, R. A. 2003. Inheritance of scald resistance from barley lines 4176/10/n/3/2/6 and 1451-2. Can. J. Plant Sci. 83: 417-422. Scald incited by Rhynchosporium secalis (Oud.) J.J. Davis is an important fungal foliar disease of barley (Hordeum vulgare L.) that can cause significant yield and quality losses. While application of fungicides and/or cultural practices are possible control methods, the use of genetic resistance is a very desirable control strategy. Two New Zealand barley lines, 4176/10/n/3/2/6 and 1451-2, derived from interspecific crosses, were evaluated in scald nurseries at Lacombe and Edmonton, AB, in 1998 and exhibited a high level of resistance. The objectives of this study were to further evaluate the level of resistance in these lines under western Canadian conditions and to study the inheritance of that resistance. Lines 4176/10/n/3/2/6 and 1451-2 were each crossed with the scald susceptible cultivars CDC McGwire and RFLP Harrington. A scald screening nursery at Lacombe, AB, was utilized for disease testing in 1999 and nurseries at Lacombe and Edmonton, AB, were used in 2000. The F-1 and F-2 generations of all resistant/susceptible crosses were evaluated in 1999. One hundred F-4:5 recombinant inbred lines from each cross were evaluated in replicated trials in 2000. Lines 4176/10/n/3/2/6 and 1451-2 were resistant in all trials and resistant/susceptible populations segregated for single gene control of resistance in the F-2 and F-4:5 generations. Chi square analysis indicated that they possess a single dominant gene for resistance. These two lines should provide simply inherited sources of scald resistance for western Canada.