Eight-year performance of 19 peach rootstocks at 20 locations in North America

Nineteen Prunus rootstock cultivars and selections budded with 'Redhaven' peach were planted at 20 locations in North America in 1994 as an uniform planting of the NC-140 Cooperative Regional Rootstock Project. The rootstocks included peach seedlings from 'Lovell', 'Nemaguard', 'Bailey', 'Tennessee Natural 281-1', 'Stark's Redleaf', 'GF 305', 'Higama', 'Montclar', 'Rubira', 'Chui Lum Tao', 'Tzim Pee Tao', 'H7338013', 'H7338019', 'BY520-8', and 'Guardian™ BY520-9'. Clonal rootstocks included 'Ishtara', 'Myran', 'S.2729', and 'Ta Tao 5' interstem on 'Lovell'. Data were summarized across the 20 sites in 18 states and provinces over eight years. Tree survival was lowest in the Michigan, Indiana and southeastern Missouri plantings and best in Arkansas, Kansas, Maryland, New York, South Carolina, and Utah. Trunk circumference was largest in southern Illinois, central Tennessee, southeastern Missouri, and central New Jersey. 'Myran' was the most vigorous rootstock followed by 'S.2729' and 'Guardian™ BY520-9', 'Ishtara', 'Tzim Pee Tao', and 'Chui Lum Tao' produced the smallest trees. Full bloom date was significantly advanced (< 1 day) on 'Myran' rootstock and delayed (1-5 days) on the 'Ta Tao 5' interstem. Fruit maturity was advanced <1 day on 'Myran' and 'Tennessee Natural 281-1' and delayed 1-4 days on 'Ta Tao 5' interstems when compared to 'Lovell'. The effect of 'Ta Tao 5' on bloom and ripening delay in days was more prolonged in the South (i.e., Georgia, South Carolina). Fruit weight was significantly influenced by rootstock as 'Redhaven' fruit from 'BY520-8' and 'Ta Tao 5' interstem trees were smaller (∼10 g) and fruit from 'Ishtara' and 'H7338013' were larger (6-7 g) than fruit from trees on 'Lovell'. Cumulative fruit yield (1996-2001) significantly varied among rootstocks, and yield differences were evident between locations as the highest cumulative fruit yields were from Ohio, north central New Jersey, Maryland, and South Carolina. No rootstock yielded significantly more than 'Lovell'. However, 'GF 305', 'Montclar', 'Guardian™ BY520-9' and 'H7338019' yielded equivalent to 'Lovell'. In contrast, 'Ishtara', 'Chui Lum Tao', 'Tzim Pee Tao', 'Bailey', 'Higama', and 'Rubira' and the 'Ta Tao 5' interstem trees often had significantly lower yields than 'Lovell'. Relative ranking of cumulative yields according to rootstocks and geographic locations tended to remain unchanged after the fifth year.