-18- 



Effects of rootstock on nutrient uptake and movement may vary among locations 

 due to orchard conditions, tree age, variety and crop load. Nevertheless, appropriate 

 preventative measures may be necessary before planting trees on M27 rootstocks 

 where manganese has been associated with internal bark necrosis on Delicious apple 

 trees. 



Fruitfulness and fruit size. No rootstock or stempiece/rootstock combination 

 consistently influenced bloom or fruit set although it is well known that M9 rootstock 

 can induce early precocity and limited data show that rootstocks can influence fruit 

 set. The trees fruited in their 3rd growing season but yields were low until the 6th 

 growing season. After 8 growing seasons it was found that trees on M26, 9/106 and 

 27/106 were more productive than those on 9/111, 1V19 and M27. However, when 

 fruitfulness was related to trunk girth, production efficiency did not differ among 

 the trees on the various rootstock and stempiece/rootstock combinations. There 

 was no consistent influence of rootstock or stempiece/rootstock combinations on 

 fruit size of 'Empire' in this study. 



Individual trees within the rootstock and stempiece/rootstocks combinations became 

 somewhat biennial. Heavy cropping during the 7th or 8th growing seasons combined 

 with the tendency of 'Empire' to produce small fruit, indicated the need to chemically 

 thin this variety to enhance fruit size and to prevent biennial bearing. 



Fruit maturity. Fruit from trees on 27/111 ripened later than those from trees on 

 the other rootstock and stempiece/rootstock combinations. However, the delay in 

 ripening was small and probably of no commercial importance. 



Data cited above indicated that IV127 and M9 were equally suitable as stempieces. 

 No interstem combination showed an advantage over the lower-priced singly-worked 

 trees on M26 although MMlll is reported to be adapted to a greater variety of soils 

 than M26. We concluded that interstem trees will require a higher level of management 

 that is usually given trees on more vigorous size-controlling rootstocks in northeastern 

 United States. 



