The Chromosome Stability of Hordeum Vulgare L.-H. Bulbosum L. Chromosome Substitution Plants Grown at two Temperatures

Abstract

The perennial wild species Hordeum bulbosumis closely related to cultivated barley (H. vulgare) and possesses useful traits such as disease resistance. Introgression of desirable genes into barley has recently been achieved by backcrossing fertile triploid hybrids between H. vulgare (2x) and H. bulbosum (4x) to barley. Single and double monosomic chromosome substitution plants were also developed from similar crosses, but consistent chromosome pairing and stability has been difficult to achieve. Since temperature influences chromosome behaviour in H. vulgare×H. bulbosum hybrids, the effect of two temperatures (15 and 21°C) on dividing somatic ovary wall cells and pollen mother cells was investigated. At 21°C, most of the plants contained higher proportions of cells with less than the full chromosome complement, indicating elimination of the H. bulbosum monosomes. However, at 21°C, homoelogous chromosome pairing tended to be greater than at 15T. To promote high chromosome pairing and stability, optimum temperatures should be further determined to enable genetic recombination to take place.