Starking and Starkrimson strains. 



Fruit Shape Alterated by Growth Regulators 



M.W. Williams and E.A. Stahly, in Washington, found that 

 applications of cytokinins and gibberellins , alone and in com- 

 bination, to Delicious apples just after full bloom affected fruit 

 shape by increasing their length. (Effect of cytokinins and 

 gibberellins on shape of 'Delicious' apple fruits. Jour. Amer. Soc. 

 Hort. Sci . 94: 17-19, 1969). Cytokinin-treated fruits were longer 

 than normal with prominent, well-developed calyx lobes, whereas 

 those treated with gibberellins were merely longer. They postulated 

 that the influences of temperature, crop size, and fruit location 

 in the cluster on fruit shape were very likely related to their 

 effects on the levels of gibberellins, cytokinins and other naturally 

 occurring growth regulators in the developing fruits. 



Fruits can become flatter by application of Alar-85*. Because 

 of this undesirable response plus possible fruit size suppression 

 on Delicious we prefer using 2 , 4 , 5 - TP for preharvest crop con- 

 trol rather than Alar-85. Williams in 1975 (Carry over effect of 

 ethephon on fruit shape of 'Delicious' apples. HortScience 10: 523- 

 4) reported that ethephon applied to Delicious apples before harvest 

 to improve fruit quality also can flatten fruit the following year 

 if applied to trees of medium to low vigor. 



Promalin to Lengthen Delicious 



Promalin, a plant growth regulator formulation containing 

 gibberellins and cytokinin, when tried in several areas of the 

 United States, has lengthened Delicious apples, increased their 

 weight, and improved development of the calyx lobes. We have con- 

 ducted limited tests with Promalin because of grower interest 

 in increasing the "typiness" of Delicious and the possibility of 

 increasing yields due to increased volume of the fruit. 



In 1975, 1 pint of Promalin/per 100 gallons of water applied 

 at late petal fall at our Horticultural Research Center did not 

 increase the "typiness" of Richared Delicious apples. We enlarged 

 our trials in 1976 and added surface active agents glyodin and 

 Triton B-1956 to 2 of the treatments (see Table 1 on the next 

 page). 



Fruit set was not influenced by the treatments. However, the 

 length of the Delicious as indicated by the L/D ratio was increased 

 by the 1/2 pint of Promalin when applied with glyodin or Triton B- 

 1956, and also by 1 pint of Promalin; the higher the L/D ratio the 

 longer the apple -- a "typey" Delicious will have a L/D ratio of 

 1.00 or greater. 



It is of interest to note that although Promalin increased the 

 length of the Delicious the difference could not be detected by 

 visual observation before harvest but could be seen on the harvested 



*Trade Name 



