The relationship between frost tolerance and generative induction in winter wheat (Triticum aestivum L.) under field conditions

Abstract

. 2009. The relationship between frost tolerance and generative induction in winter wheat (Triticum aestivum L.) under field conditions. Can. J. Plant Sci. 89: 1031Á1039. The quantitative nature of the vernalization and photoperiod requirements and the interference of plant age with these mechanisms complicate predictions of generative induction and its relation to frost tolerance. This study was designed to dissect further the course of development towards full generative induction and to time the stages in frost tolerance. Two cultivars of winter wheat were regularly sampled from fields at four sites during three winters. The apex stage of development was observed at time of sampling and after 3 subsequent weeks of growth at 188C, under either short or long days. Level of frost tolerance at sampling was also recorded. No visible change in apex appearance was found at time of sampling, but readiness of plants to initiate generative development was enhanced. Vernalization by low temperatures alone was not enough to induce the plants into generative development or initiate loss of frost tolerance. Short day conditions after sampling delayed the appearance of double ridges by 6Á9 wk as compared with long day conditions. The timing of maximum frost tolerance and its subsequent decrease indicated that generative induction under the short day conditions prevailing in field occurred about 1 mo after vernalization saturation.

Allelic variation and differential expression of VRN‐A1 in durum wheat genotypes varying in the vernalization response

“…Flowering time influences the adaptability of wheat plants to a large range of environments. Plants can sense environmental signals and delay flowering under favourable seasonal conditions, thus preventing freezing damage to sensitive reproductive tissues (Bergjord et al 2009). In addition, earliness in flowering is an effective means to avoid high-temperature stress effects during grain filling, particularly in Mediterranean climates.…”

Model prediction of frost tolerance as related to winter survival of wheat in Finnish field trials

“…It has been shown that the induction of generative development may be delayed beyond vernalization saturation by the absence of long photoperiods (Slafer and Rawson 1996, Mahfoozi et al 2001a, 2001b, Danyluk et al 2003). An experiment performed by Bergjord et al (2009) indicated that the induction, and consequently the reduced ability to gain and maintain a high level of frost tolerance, was delayed for about one month after vernalization saturation by the absence of long photoperiods. The amount of available data was, however, too scarce to develop a reliable functional relationship between photoperiod and the timing of generative induction in FROSTOL.…”