Chicory (Cichorium intybus L.) can beat the heat during summer drought in southeast Australian dairying regions

Perennial ryegrass (Lolium perenne L.) is the major sown pasture species in southeast Australian dairying regions. Ryegrass is not only intolerant of soil moisture deficits, but heat waves, which increasingly present a challenge to summer home-grown feed production. To address this challenge a screening experiment was undertaken to identify temperate perennial forage species better adapted to combined heat wave stress and soil moisture deficits. Responses of ten perennial forages to optimal and heat wave temperature regimes (day/night ambient temperatures of 23/15˚C and 38/26˚C) were evaluated under glasshouse conditions. The effect of moisture availability (optimal watering or no water) and the recovery capacity of plants grown in optimal conditions (day/night ambient temperature regime of 23/16˚C; optimal watering) for 18 d after stress periods ceased were also examined. Chicory (Cichorium intybus L., cv. Grasslands Puna) had a superior tolerance to heat stress and moisture deficit compared with ryegrass cv. Samson. Chicory not only maintained live above-ground tissue after exposure to the combined stress for 18 d, but increased in yield by 46% during the recovery period. In contrast at 12 d, live tissue was not detectable in the ryegrass, with yield measurements indicating plants unable to recover. Results suggest that under dryland conditions chicory may enable a greater level of home-grown feed production to resume following an extended heat wave compared to ryegrass.