Winter hardiness is a complex plant characteristic that includes resistance to freezing, smothering, waterlogging, frost heaving, and winter desiccation. Unlike frost resistance, which is limited to tolerance of low temperatures, winter hardiness takes into account the entire spectrum of adverse effects that lead to plant death or damage during the cold period.
The winter hardiness of a variety is evaluated using methods of field assessment of crop conditions after winter, employing scoring scales, as well as laboratory studies. The latter include direct freezing of plant monoliths, biochemical analyses of sugar accumulation, verification of the viability of the tillering node, and the use of genetic markers to determine resistance.
The level of winter hardiness depends on the genetic potential of the variety, the plant's ability to harden, agronomic cultivation practices, and the microclimate characteristics of a specific site. When choosing a variety, one should focus on regionalized forms, bearing in mind that the resistance indicator is relative and requires comparison with local standards and growing conditions.