Identification of loci on chromosome 5A of wheat involved in control of cold hardiness, vernalization, leaf length, rosette growth habit, and height of hardened plants

The offspring from crosses of 'Cadet' by 'Cadet – Rescue 5A' and 'Winalta' by 'Winalta – Rescue 5A' were studied to obtain information on the inheritance of cold hardiness, winter–spring growth habit, rosette growth habit, height of cold-hardened plants, and length of leaves of hardened plants. The results indicate that a minimum of two loci on chromosome 5A are involved with cold hardening. One locus controls hardiness in part and is tightly linked to the one that controls in part the length of leaves of hardened plants. The other locus is, or it tightly linked to, Vrn1, a winter-spring growth habit locus. This locus may also control part of rosette growth habit. It is postulated that Vrn1 is involved in sensing temperature and in part triggering vernalization, cold hardening, and the development of the rosette growth habit. If so, Vrn1 could code for production of a temperature-sensitive protein, which undergoes conformational changes with changes in temperature.Key words: Triticum aestivum L., cold hardiness, vernalization, rosette growth habit, plant height, leaf length, temperature sensing.