Effect Of Several Pruning Practices On Photosynthesis, Growth And Fruiting In Red Fuji Apple High-Density Orchards

This experiment has studied the effects of four pruning practices with 10 years old Fuji apple / M26 in Shaanxi province. The results showed that all the four main measures can improve leaf photosynthetic activity,leaf and fruit quality.1. The result shows that all the pruning practices have improved apple leaf photosyn- thetic characteristics and the leaf quality in the middle or below canopy. The measures of combine increasing tree trunk and reducing tree height done well in all the practices,and LevelⅪis the most marked practices.2. The practice of reducing orchard density is able to increase flower-buds polarization and the number of long and middle shoot. In the increasing trunk height measures, flower-buds polarization reduced clearly while the trunk height more than 1.2 m. In the reducing tree height measures,flower-buds polarization reduced with the tree height lower. Only the branches number decease obviously when the tree trunk height is 1.2～1.3 m. Reducing orchard density and reducing tree height effected new shoots bourgeon little, when the trunk height is more than 0.9 m,new shoots bourgeon and its long shoot number is small. The long shoot proportion in the measures of combine increasing tree trunk and reducing tree height took the most part in all shoot.3. The gap fraction in the measure of increasing trunk height is high. The tree canopy openness increased ,when increase trunk height more than 0.9 m or it be combined with reducing tree height measure to the tree height under 2.8 m. The measure of reducing orchard density increase the LAI,but increasing trunk height and reducing tree height measures put the LAI down. So almost all the management practices improve the index of DTFN,PPFD and Total Site Factor.4. The measure of reducing orchard density increase the grain yield per tree. In the measure of increasing trunk height,with the trunk height increase the grain yield becoming lower. It has not obvious difference in grain yield to the measure of reducing tree height. Almost all the management practices improve the index of fruit color,hardness,main fruit weight,anthocyanidin, content soluble solids and titratable acidity. The result illustrated that the best measure of managing apple is keeping the orchard density about 840 Trees per ha.,trunk height between 0.9-1.0 m and tree height between 2.2-2.4 m.