VERNALIZATION RESPONSES OF A SELECTED GROUP OF SPRING WHEAT (Triticum aestivum L.) CULTIVARS

Abstract

Ten spring wheat (Triticum aestivum L.) cultivars were assessed for the pattern, duration and stability of their response to vernalization and the effect of plant age on receptivity to cold treatment. Cold treatment intervals of 0–6 wk were used to determine the patterns of response. Cajeme 71, Fielder and Pitic 62 were found to have a gradual response with the vernalization requirement satisfied after 4 or 5 wk of cold treatment. Benito, Glenlea, Marquis, and Neepawa had slight but significant responses to longer cold treatments (5–6 wk). Yecora 70, Prelude and Sinton were nonresponsive to the cold treatments. The development of the vernalization responses in Cajeme 71 and Pitic 62 was assessed with cold treatments of 0, 1, 4, 8, 16 and 32 days in a greenhouse study. The pattern of response consisted of a lag period, a period of rapid induction, and finally a plateau when the vernalization requirement was filled. Intermediate temperature treatments of 1–6 days at 15 °C stabilized the vernalization response induced by 2 wk of cold treatment (4 °C) in Fielder and Pitic 62 and by 6 wk of cold treatment in Cajeme 71. Pitic 62 was responsive to cold treatments at ages 0 and 7 days, with the responsiveness decreasing with increasing age. Neepawa, at the ages tested, was relatively non-responsive to the cold treatments.Key words: Wheat (spring), vernalization response, temperature, plant age