FACTSHEET Summer dormancy in temperate forage plants

One of the most potent of these drought survival traits is summer dormancy. Plants that give either nil or minimal growth after rainfall or irrigation in summer are expressing summer dormancy. There have been several field experiments conducted over the recent drought periods where grasses with the summer dormancy trait have had much better survival over extended and intensely dry periods than other grasses without the trait. For example, at Barellan, NSW in the late 1990’s Norton et al (2001) demonstrated a significant survival advantage for grasses with this trait, and similar advantages were shown in droughts of the current decade at Barmedman, NSW, Wagga Wagga, NSW and Warrak, Victoria by Hackney et al (2006), Hayes et al (2010) and Nie (2009). In further research Norton et al (2006a; 2006b) quantified the survival advantage given by the summer dormancy trait over long, severe summer droughts and showed in cocksfoot that the dormant cv. Kasbah had 28 % greater survival than non-dormant cv. Medly and in tall fescue the dormant cv. Flecha had 30 % greater survival than the non-dormant cv. Demeter.