Cold Hardiness Potential of Triticale and Teraploid Rye1

Abstract

Cold hardiness is the primary factor restricting the area of winter wheat (Triticum aestivum L. em Thell.) production in North America. Related species are potential sources of genetic variability that could be used in the improvement of winter wheat cold hardiness. Among these relatives, rye (Secale cereale L.) has shown the greatest ability to tolerate cold. However, exploitation of this source would be feasible only if the genes for cold hardiness in rye were expressed when in association with the wheat genomes. To determine the level of this expression seven octaploid triticales were produced. These triticales and their parental winter wheat and rye cultivars were then assessed for cold hardiness in artificial freeze tests. In all instances the triticales achieved only the cold hardiness of their parental wheat cultivars. The effect of increasing ploidy level on the expression of cold hardiness in rye was also investigated. The cold hardiness of seven autotetraploid rye populations was compared with the cold hardiness of their parental diploid populations. All autotetraploid populations were not as cold hardy as the corresponding diploid populations, indicating that polyploidy has an adverse effect on the expression of genetic systems controlling cold hardiness in rye. Based on these observations, it appears that rye is an unsuitable source of genes for the improvement of cold hardiness in polyploids such as common wheat.