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.

Lucerne varieties are categorised into three main groups: semi winter dormant (5), winter active (6-7) and highly winter active (8-10).

Activity/dormancy groups

Semi winter dormant (5): Stamina^® GT5

Persistent stands with slow winter growth. In comparison to winter active types (6-7), semi winter dormant (5) varieties are well suited to grazing and quality hay production due to a lower crown and a semi-prostrate but denser growth than winter active types (6-7).

Winter active (6-7): Warrego GT6 and Titan 7

Tend to have smaller crowns with an erect growth that provides some winter growth (providing suitable temperatures). Although a multi purpose stand that provides quality hay production and grazing opportunities, strict rotational grazing management is required as winter active (6-7) lucerne varieties are comparatively less tolerant to grazing than semi winter dormant (5) varieties.

Highly winter active (8-10): Torrens GT8 and Titan 9

Good winter growth with an upright growth habit. Vigorous at establishment and fast recovery from cutting or grazing. High production for at least three years, making them a great option in cropping rotations. Strict rotational grazing management is required as highly winter active (8-10) lucerne varieties are comparatively less tolerant to grazing than semi winter dormant (5) and winter active (6-7) lucerne.

Torrens GT8 however provides growers with increased persistence compared to traditional highly winter active varieties due to its grazing tolerance and below ground budding trait.