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Promalin Studies in 1978 and Comments on Trial Use in 1979 



Duane W. Greene and William J. Lord 

 Department of Plant and Soil Sciences 



Promalin* is a plant growth regulator containing gibberellin 

 A. 7 and a cytokinin, 6-benzyladenine , in equal amounts. Its pri- 

 mary use at this time is to increase the length (^/D ratio or typi- 

 ness)l of Delicious apples, thereby making them more attractive to 

 the consumer. 



Last year we discussed factors affecting shape of apples and 

 our preliminary studies with Promalin ( Fruit Notes 43 (3): 4-7). 

 In this article we report our 1978 findings with Promalin and include 

 comments to consider when using it in 1979. 



1978 Studies 



Coverage Growth regulators commonly used in fruit production have 

 limited translocation from the site of contact with the plant. The 

 data in Table 1 indicate that the absorption and/or translocation of 

 Promalin also may be limited. 



Table 1. The effect of site of Promalin application to'Richared 

 Delicious' apple flowers on the L/d ratios of the fruits that 

 developed from these flowers. 



Treatment and microliters 



of solution applied^ L/q Ratio 



Check .93cy 



Petals, 25X .94c 



Petals, 150 .99b 



Receptacle surface, 25 1.03a 



In calyx end, 25 1.03a 



^Solution contained 50 ppm Promalin plus 0.05% X-77. 



^Numbers in a column followed by different letters are significantly 

 different at odds of 19 to 1. 



^A 25 microliter droplet was large enough to wet the receptacle 

 surface with no runoff. 



*Tradename 



: highei , . ^ . 

 apple. A "typey" Delicious will have an L/d ratio of 1.00 or greater 



''^The higher the L/d ratio (length/diameter ratio) the longer the 



