In vitro-Selection and Regeneration of Hydroxyproline-Resistant Lines of Winter Wheat with Increased Proline Content and Increased Frost Tolerance

Abstract

An embryogenic callus obtained from immature embryos of a Finnish winter wheat ( Triticum aestivum 1. cv. Jo 3063) was used for in vitro -selection of hydroxyproline (Hyp) resistant calli. Calli were plated on solid Gamborg B5 medium containing 10–20mM Hyp and 2mgL −1 2,4-D. From 6018 embryogenic calli exposed to Hyp in the course of three subcultures nine calli proved to be Hyp-resistant and remained viable and embryogenic. These were transferred to a regeneration medium and finally to Gamborg B5 medium before being transplanted to soil. The regenerated plants were grown at 18°C for 6 weeks and then cold hardened at 2°C for 18 weeks. The mean osmotic potential of the Hyp-resistant cold hardened regenerates was significantly lower than that of hardened controls. At the same time their mean proline content and their mean frost tolerance were significantly higher compared with regenerated controls.