Vernalisation Response of Some Winter Wheat Cultivars (Triticum aestivum L.)

For 17 cultivars of winter wheat (Triticum aestivum L.) different vernalisation and photoperiod responses were detected. The effect of photoperiod sensitivity was not significantly changed by vernalisation; different vernalisation responses were probably due to the presence of multiple alleles at Vrn loci. The delay in heading depended on the vernalisation deficit exponentially: y = parameter (1) + [y0 – parameter (1)] × EXP [parameter (2) × (x – x0)]. The dependence was shown to be general and significant for the given model in all the studied cultivars. Individual regressions characterised responses of cultivars to a deficit of vernalisation treatment. Cluster analysis according to the characterisation obtained (full vernalisation requirement, minimum vernalisation requirement, insufficient vernalisation and parameters of the dependence) showed the relationships between cultivars and enabled their grouping by similar profiles of vernalisation, and, possibly, of photoperiod response. In individual cultivars, an attempt was made to use the model to predict performance for some agronomic traits.