■6- 



The data from the multi-state plantings, summarized by 

 Ferree after the first 5-years of study showed that tree losses 

 occurred at all sites except in Illinois and Iowa. The highest 

 tree losses were experienced in Massachusetts and Wisconsin. 

 The losses were attributed to poor tree quality. Trees on the 

 Kentucky site experienced severe frost heaving in 1978. Regard- 

 less of rootstock, the growth on the trees was weak in 1979 and 

 they were removed in 1980. 



Tree size based on cross- sectional area was quite variable 

 among the planting sites. In general, the trees in Illinois, 

 Iowa, Kansas, Missouri and Ohio were larger than those in Massa- 

 chusetts, Michigan, Wisconsin and Indiana. Those on the Indiana 

 site were smallest. 



Compilation of the data from the 9 sites indicated that the 

 trees on MMlll were 15-201 smaller than those on Antonovka seed- 

 ling or Ottawa II. The trunk circumference and branch spread of 



the Empire trees were larger than those of Sturdeespur on com- 

 parable rootstocks. 



The trees were planted with the stempiece 2 inches above 

 the soil line and the development of root suckers had been of 

 concern on all sites. Trees on Ottawa II have tended to pro- 

 duce fewer root suckers than Antonovka or MMlll, particularly in 

 Kansas, Massachusetts and Ohio. Trees in Missouri and Ohio 

 produced nearly twice as many suckers as in other states. Of 

 particular interest in areas where fireblight is of major concern 

 is the fact that several states observed fireblight strikes on 

 Antonovka root suckers in 1981 . 



The trees produced their first crop in 1979 and the Empire 

 trees showed the tendency to bear earlier than Sturdeespur Deli- 

 cious. However, adequate data are yet not available to evaluate 

 the yield efficiency of the various scion/rootstock combinations. 



Ferree summarized the preliminary findings from the multi- 

 state interstem planting by stating "...it is clear that signi- 

 ficant differences exist in root suckering potential of vigorous 

 rootstocks used as root systems for interstem trees. An assoc- 

 iation also appears to exist between increased suckering and 

 vigorous scion growth. We have also confirmed that producing inter- 

 stem trees through double grafting should be avoided because of 

 poor tree quality and general lack of vigor is considered as a 

 major factor contributing to poor early tree performance in 

 several of the test sites". 



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