Reduction of shoot growth and winter pruning in apple trees treated with prohexadione calcium.

摘要

The mild climate and extended growing season of Brazil results in more shoots growth on semi-dwarfing apple trees than in other apple growing areas of the world. We conducted several experiments from 2005 to 2007 with Prohexadione Ca to evaluate its potential to reduce shoot growth and pruning labor. When Prohexadione Ca was applied twice per season (20 and 50 days after full bloom) at 320 g ha-1, shoot length and shoot number of 'Gala' and 'Fuji' on M.7 rootstock was reduced significantly as well as the number of shoots removed by winter pruning. The reduction in shoot numbers was more pronounced than the reduction in shoot length. Yield after two years of application was also increased by applications of Prohexadione Ca. Prohexadione Ca also effectively reduced growth in a two-year old apple orchard when applied after bloom.