Chromosome Location of Mature Plant Leaf Rust Resistance in Chinese Spring Wheat

Athwal and Watson (1957) reported that the wheat cultivar Chinese Spring W1806t possessed a single dominant gene for mature plant resistance to leaf rust (Puccinia recondita Rob. ex Desm.) and that this gene was allelic with one of two factors in Uruguay W1064. The second factor in Uruguay, operative in both seedling and mature plant stages, was located on chromosomes 5D(XVIII) (McIntosh, Baker, and Driscoll 1965). Uurau (1950) presented F2 and Fs data for crosses involving certain Chinese Spring monosomic lines with the susceptible cultivar Federation 41. His results were inconclusive in associating resistance with a specific chromosome. The behaviour of the Chinese Spring resistance with regard to dominance has been found to vary in different investigations. In addition to the report of Athwal and Watson, Unrau found that the segregation pattern in crosses with Federation 41 indicated that resistance was governed by a single, incompletely dominant pair. On the other hand, Macindoe (1948) reported that a recessive gene for resistance was involved.