-17- 



Effects of Rootstock and Stempiece/Rootstock Combinations on Growth, Leaf Mineral 

 Concentrations, Yield and Fruit Quality of 'Empire' Apple Trees! 



W.J. Lord, D.W. Greene, R.A. Damon, Jr. and J.H. Baker 

 University of Massachusetts, Amherst 01003 



A study of 8-year duration was recently completed in which we studied the 

 vegetative growth, leaf mineral concentrations, fruiting and fruit quality responses 

 of 'Empire' apple trees on M26, M9, M27, M9/MM106, M9/MM111, M27/MM106 and 

 M27/MM111. The stempieces were 8 inches (20 cm) in length. Our summary and 

 conclusions from this study are below. 



Growth. It was difficult to train, without temporary support, trees on M26, 9/106, 

 9/111, 27/106 and 27/111 because of leader leaning. Leader leaning appeared associated 

 with the growth characteristic of 'Empire' rather than an excessive crop load. Since 

 this problem also has been encountered with other varieties on M26 or interstems, 

 we concluded that it may be frequently necessary to provide support for the central 

 leader until the trees have obtained the height and volume desired. 



Interstem trees on MMlll produced more root suckers than those with MM106 as 

 the understock. Trees on M27 produced no root suckers. The root suckering was 

 not particularly troublesome on the interstem trees probably because all but 2 inches 

 of the stempiece was planted below ground and maintained by periodic removal or 

 addition of top soil. Costante et al. in Vermont showed that interstem trees planted 

 with most of the stempiece beneath ground had less root suckers and problems 

 associated with burrknots on the stempieces. 



Height and spread of trees on M26, 9/106, 9/111, 27/106 and 27/111 were similar, 

 and they were larger than those on M9 and M27. The data disagreed with the suggestion 

 by nurserymen that a M27 stempiece on either MM106 or MMlll will produce a tree 

 approximately the size of the same cultivar on M9 rootstock. 



M27 appears too dwarfing to be of value under less than extremely favorable 

 growing conditions and a high level of management. However, Tukey in Pennsylvania 

 predicts off bright future for this rootstock as the industry shifts to virus-tested 

 rootstocks which induce high vigor. 



Leaf mineral concentrations. The rootstock and stempiece/rootstock combinations 

 influenced leaf phosphorous, magnesium, boron, manganese, and aluminum in 'Empire' 

 scion foliage but the differences were small except for manganese levels in trees 

 on M27. Manganese level in leaves from trees on M27 was much higher than those 

 for trees on the other rootstock and stempiece/rootstock combinations. 



This study was funded in part by grants from the International Dwarf Fruit Tree 

 Association. 



