Advantages of endophyte infection for irrigated pastures of semiarid cold-desert environments

Little research has evaluated possible endophyte benefits to adaptation and production of grasses in the irrigated pastures of the semiarid, cold-desert environments of the western USA. Severe irrigation shortages are common; however, production demands are increasing, necessitating maximizing tall fescue's (Festuca arundinacea Schreb.) productivity when grown in sub-optimal conditions including drought, salinity, and cold temperatures. In a field study under irrigation in the Intermountain Western USA, the yield advantage to Kentucky 31 tall fescue infected with wild-type Neotyphodium over endophyte-free Kentucky 31 was greatest (over 15%) when irrigation was severely limited to natural precipitation. In an evaluation of salinity tolerance there were no significant differences in plant LD50 values due to endophyte infection. In a recent study Jesup MaxQ recovered better from winter injury than Jesup E- when grown in a high-elevation colddesert, irrigated environment. These studies suggest the need for additional research to elucidate the potential advantages of wildtype and novel endophytes for tall fescue production in irrigated environments typical of the semiarid western USA. Keywords: tall fescue, Festuca arundinacea Schreb., Neotyphodium, drought tolerance, salinity tolerance, winterhardiness