The development of super-hardy winter wheat cultivars: identifying the pieces of the cold hardiness puzzle
Peer Reviewed StatusNon-Peer Reviewed
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Several years of investigation of the genetics of cold hardiness in wheat, and attempts to improve the cold hardiness of this crop, have identified a number of 'pieces' in the cold hardiness puzzle. The cell cytoplasm does not appear to have any direct effect on cold hardiness, nor on the expression of nuclear genes affecting cold hardiness in wheat or its relatives. Cold hardiness appears to be controlled mainly, although not exclusively, by additive gene action. The most promising source of new genes for the improvement of cold hardiness in wheat appears to be from the rather distantly related wheatgrass group and rye. The chromosome doubled hybrids of rye and crested wheatgrass with wheat exhibited none of the superior cold hardiness found in these donor species. Three explanations were found which help to explain the expression of these alien genes in a wheat background: 1) specific wheat chromosomes were found to affect the expression of rye genes, 2) the species contributing the greatest number of chromosomes in an interspecific cross has the greatest influence on cold hardiness, and 3) increasing the chromosome number, as when the chromosome number is doubled to make an interspecific hybrid fertile (e.g. Triticale), results in an increased cell size which gives the plant less cold tolerance than would be genetically expected. Small cell size was also found to be a factor related to cold hardiness within wheat cultivars. Methods for the improvement of cold hardiness in winter wheat are proposed based on these findings.
Part OfSoils and Crops Workshop
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