Cold Hardiness in Hexaploid Triticale.
A.E. Limin, J. Dvorak and D.B. Fowler

ABSTRACT

The excellent cold hardiness of rye (Secale cereale L.) makes it a potential source of genetic variabilny for the improvement of this character in related species. However, when rye is combined with common wheat (Triticum aestivum L.) to produce octaploid triticale (X Triticosecale Wittmaek, ABDR genornes), the superior rye cold hardiness is not expressed. To determine if the D genome of hexaploid wheat might be responsible forth is lack of expression, hexaploid triticales (ABR genomes) were produced and evaluated for cold hardiness. All hexaploid triticales had cold hardiness levels similar to their tetraploid wheat parents. Small gains in cold hardiness of less than 2°C were found when very non-hardy wheats were used as parents. This similarity in expression of cold hardiness in both octaploid and hexaploid triticales indicates that the D genome of wheat is not solely, if at all, responsible for the suppression of rye cold hardiness genes. There appears to be either a suppressor(s) of the rye cold hardiness genes on the AB genomes of wheat, or the expression of diploid rye genes is reduced to a uniform level by polyploidy in triticale. The suppression or lack of expression, of rye cold hardiness genes in a wheat background make it imperative that cold-hardy wheats be selected as parents for the production of hardy triticales.

Keywords

Triticale, Secale , winter wheat, cold hardiness, gene expression

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