FIELD PERFORMANCE OF FIRE BLIGHT TOLERANT, PYRUS COMMUNIS SELECTIONS IN SOUTH CAROLINA

Six pear cultivars and nine advanced P. communis selections having fire blight tolerance, plus ‘Bartlett’, were planted in 1996, 1997 or 1998 near Clemson, South Carolina. Disease resistance, tree growth, phenology, precocity, fruit maturity and fruit weight and yield were evaluated through 2003. Among the cultivars and selections, almost all exhibited some leaf bronzing, necrosis and partial defoliation by mid-summer in 2001 and 2002. However, selection 78304-057, ‘Harrow Sweet’, and ‘Stark Honeysweet’ had few or no leaf symptoms. ‘Starking Delicious’ was the most vigorous cultivar followed by ‘Potomac’, 76128-009 and ‘Harrow Delight’. Mean full bloom dates among P. communis cultivars and selections varied by 10 days with only 78304-057 blooming later (3 days) than Bartlett. Secondary or rattail flower production was common in most years for selections 76128-009, 66125-035, and ‘Harrow Delight’. Cumulative fruit yields per tree were highest in ‘Potomac’ (138 kg), 76128-009 (131 kg), ‘Starking Delicious’ (120 kg), and 78304-057 (111 kg). The lowest yielding cultivar planted in 1996 was 66131-021 (‘Blake’s Pride’). Largest mean fruit weights were from NY10346 (285 g), 76115-010 (253 g), ‘Bartlett’ (242 g), and 67218-083 (233 g). Average fruit maturity date based on pressure readings among cultivars and selections varied by 38 days. ‘Harrow Sweet’ and NY10346 were the only 2 pears to ripen (~10 days) after ‘Bartlett’. ‘Harrow Delight’, 66170-047, 71655-014, and 76115-010 ripened the earliest, ~ 4 weeks before ‘Bartlett’. No cultivars or selections were significantly injured by fire blight through 2003.