Agronomic performance of AR37-infected ryegrass in northern New Zealand

Abstract

The agronomic merits of a perennial ryegrass (Lolium perenne) cultivar infected with a new endophyte (Neotyphodium lolii), AR37, were compared with the same cultivar infected with currently available endophytes (AR1, Standard) at two sites in northern New Zealand for at least 3 years. AR37-infected ryegrass was the highest yielding treatment at both sites (11 080 kg DM/ ha/yr) producing more dry matter than either AR1 or Standard-infected ryegrass which yielded similar amounts (8870 kg DM/ha/yr). Yield advantages of AR37-infected ryegrass were greater at Kerikeri (36%) than Hamilton (17%), with differences increasing over successive years at both sites. At Hamilton, tiller populations were lowest in AR37-infected ryegrass in Year 2, and lowest in AR1- infected ryegrass 3 and 5 years after sowing. At both sites AR37-infected ryegrass had the lowest infestation scores for root aphid. At Hamilton in Year 4, more damage by African black beetle larvae occurred to AR1-infected plants than to AR37 and Standard-infected plants. These pests are likely to have contributed to the differences in agronomic performance observed. These agronomic results suggest AR37-infected ryegrass cultivars will be a useful choice for farmers in northern New Zealand. Keywords: endophyte, Neotyphodium lolii, perennial ryegrass, Lolium perenne, dry matter yields, plant persistence, root aphid, Aploneura lentisci, African black beetle, Heteronychus arator