Relation between shoot vigour and bud necrosis in 'Campbell Early' grapevines

Abstract

This study was carried out to investigate the incidences of main, accessory and axillary bud necrosis in different node position and cane vigour in 'Campbell Early' grapevines. Main bud necrosis of 'Campbell Early' grapevines occurred from 30 days after full bloom, increased sharply during 50 similar to 60 days after full bloom, and increased slowly from 60 to 120 days. Although rate of accessory bud necrosis was lower than main bud necrosis, main and accessory bud had same necroses pattern. Main bud necrosis occurred earlier and higher in the basal buds (1st to 3rd buds) than the more distal buds on a shoot. But as plant grew, main bud necrosis increased in the buds of middle position in shoot (4th to 9th buds) at 50 similar to 60 days after full bloom. At rest stage, the mean incidence of main bud necrosis was 28.6% in weak canes (shoot diameter below 8.0 mm), 58.0-77.6% in moderate canes (8.1 similar to 11.0 mm) and 96.8% in very vigorous canes (above 11.1 mm). Incidences of main bud necrosis in different longitudinal bud sizes were 22.4% in 4.1 similar to 5.0 mm, 49.2% to 53.8% in below 4.0 nun and 60% in above 5.1 mm respectively. As vine age shoot is produced strongly, thus main bud necrosis in the vines showed a tendency of continuous increase with their growth.