Understanding Dormancy

Selecting the correct lucerne cultivar for your system will go a long way to determining the success of your stand.

The first step is to match the dormancy type you require to suit your environment and your production system.

Winter activity (also known as winter dormancy or fall dormancy) is determined by the amount of regrowth produced in the autumn-winter months following the final harvest of the spring-summer growing season. It is generally measured on a scale 1 to 10, with a dormancy/activity rating of 1 (equal to “very winter dormant” expressing no winter growth), to 10 (expresses high winter activity with high regrowth potential and classified as “highly winter active”).

This expression of dormancy characteristic is the plant genotype’s response to the environment. For example, shortening day lengths and decreasing temperatures will result in the expression of a winter dormant cultivar’s dormancy period.

The dormancy of a lucerne variety and where it is being grown determines the length of the growing season. Lucerne can grow all year round, with higher growth rates in spring and summer and slower growth rates during the autumn and winter. Lucerne cultivars can vary significantly in their late autumn to winter growth, depending on dormancy classification. This also has a significant influence on what management or requirements a producer has for their lucerne stand.

Highly winter active cultivars are better suited to high yield potential environments, where the winter growth can be successfully utilised. Winter active varieties will stop growing actively later in the autumn and start earlier in the spring than the more dormant cultivars. 

NOTE: Informtation below relates to lucerne in general. As a highly winter active grazing tolerant lucerne, Torrens GT8 has the potential to persist for 5 plus years in comprison to traditional highly winter active lucern's. 

Dormant and semi-dormant cultivars generally persist longer than winter-active cultivars, although there are exceptions to this rule.

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