Abstract:

Effects of different dwarfing interstocks of SH series on growth，light distribution，yield and fruit quality in‘Fuji’apple trees were in-depth studied to provide the theoretical basis and mentoring programs for the selection of suitable dwarfing interstock. The‘Fuji’apple with different SH dwarf interstocks（SH1，SH3，SH6，SH9 and SH40）planted in spring 2009 was used to investigate the dynamic changes of tree growth，light distribution，yield，single fruit weight and fruit quality in 2016. The spacing is 1.5 m × 5.0 m，spindle pruning. There are big differences in the tree growth，light distribution，yield and fruit sugar and acid constituents between‘Fuji’apple trees with different SH dwarf interstocks. After planting for eight years（2016），there was no significant difference in stem and panicle ratio between‘Fuji’apple trees with different SH dwarf interstocks. The trees with SH1 and SH6 interstocks are the shortest，while the trees with SH40 interstocks are the tallest. The crown of the apple tree with SH40 interstock is the largest. The stem diameter of different dwarf interstocks from big to small is SH40，SH3，SH9，SH6 and SH1. The total number of branches of each interstock tree is more than 1 400 000 per hm2. The ratio of short shoots of the trees with SH6 dwarfing interstock was the highest. The average relative light intensity of each tree canopy was SH3（72.88%），SH6（70.85%），SH9（65.51%），SH1（62.23%）and SH40（61.82%）. The proportion of SH6 tree relative to light intensity less than 30% and 40% is minimum，only 2.08% and 4.17%. The cumulative yield of the tree with SH6 interstock was the highest in four years（2013—2016），and the yield stability was the best. The yield of the tree with SH1 interstock was low，and the yield stability of SH9 tree was bad. The proportion of big fruits from high to low in order is SH40 > SH6 = SH3 > SH9 > SH1. The average fruit weight from high to low in order was SH40 > SH6 > SH9 > SH3 > SH1. The content and ratio of sugars of different interstocks in apple fruit from high to low：fructose，sucrose，glucose and sorbitol. Different sugar content and proportion of fruits of different interstock showed significant difference. There was no significant difference between the total acid content of fruit in different interstocks，content and ratio of different acids of different interstocks from high to low：malic acid，citric acid，oxalic acid，tartaric acid. The content（except oxalic acid）and proportion of different interstock fruit acid had no significant difference. The ratio of sugar to acid in SH6 fruit was the highest，significantly higher than that in SH1，SH3 and SH9. Considering the growth and yield of trees，SH6 as a dwarfing interstock performs better.

Key words: apple, SH dwarf interstock, tree growth, light distribution, yield, single fruit weight, fruit sugar and acid component