The influence of cold tolerance and flowering time genes on perennial wheat habit

Wheat (Triticum aestivum L.) is either a spring or winter annual, completing its life cycle in one growing season. Perennial plants grow over multiple years, alternating between vegetative and reproductive phases. Perennial wheat would be a valuable innovation in agriculture with economic and environmental advantages. To develop perennial wheat, it is often crossed with a close perennial relative, wheatgrass (Thinopyrum spp.). However, these perennial wheat lines are only weakly perennial, generally dying before the second growing season. We hypothesize that perennial habit is dependent on cycling control between the vegetative and reproductive phases, involving altered gene expression and the development of sufficient cold hardiness to successfully overwinter. To test this hypothesis, expression of cold tolerance and flowering genes were examined and quantified in perennial wheat, annual wheat and wheatgrass lines grown under varying photoperiods and temperatures.