OBSERVATIONS OF FRUIT RESEARCH ACTIVITIES IN ENGLAND 



(The following excerpts were taken from an account of ^^ • Jerome 

 Hull, Jr.'s observations made during visits to research centers in 

 southern England and published in the February 1968, issue of Michi- 

 gan State Horticultural Society Newsletter. We believe you will 

 find his observations of interest. — Editors) 



"At the Long Ashton Research Station near Bristol, I visited 

 with Dr. Bould. Bould's correlation studies between leaf nitrogen, 

 phosphorus, and potassium with plant vigor, have revealed leaf an- 

 alysis to be a sound basis for determining the nutrition status of 

 tree fruits and fertilizer needs with little regard to soil type. 

 Bould also found the effect of the nitrogen status at different 

 times of the year ^ery important. He reports that a low nitrogen 

 level in the tree at the time of floral differentiation affects 

 differentiation and that nitrogen shortage later in the season af- 

 fects embryo longevity and pollen tube growth. 



"Dr. Luckwill discussed his studies with growth retardants Alar 

 and cCC. Applications of 2,000 parts per million of Alar restric- 

 ted vegetative growth and promoted flowering of apple trees. How- 

 ever, such treatments are expensive and Luckwill does not consider 

 them practical where dwarfing rootstocks are available. He believes 

 the chemical would have merit for overcoming excessive vegetative 

 growth and inducing flower bud development. Used in such a manner, 

 only one application would be necessary since the cropping effect 

 in subsequent years would be sufficient to maintain the tree in a 

 fruitful condition. 



"Studies with pillar pruning at Long Ashton have not been en- 

 couraging. The extensive pruning or cutting necessary with this 

 system encourages excessive vigor. To be successful, pillar prun- 

 ing probably would be practical only on very poor soils or with 

 very limited rainfall. In general, English growers who have tried 

 pillar pruning have failed because excessive tree vigor has resulted. 



"Apple virus investigations at Long Ashton indicate that the 

 health status of the plant interacts with the nutrient uptake at 

 certain stages of development. Viruses have also been observed to 

 reduce the production of stooled cuttings of dwarfing rootstocks. 

 The fungus disease Phythophora catorium has been observed to inter- 

 act with the viruses killing only infected stock. Likewise, virus- 

 free rootstock has been observed to produce orchards with uniform 

 tree size, while diseased stock did not. 



Grower 



:ry 



the rotation of the 3 differ 

 of the 3-year-old wood, it i 



