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ETHEPHON (ETHREL*) ON McINTOSH: 

 RED COLOR WITHOUT RIPENING 



W.J. Bramlage, M^.J. Lord, and D.W. Greene 

 Department of Plant and Soil Sciences 



Ethephon (Ethrel*) has been used in Washington to increase red 

 color o£ Delicious apples without reducing the storage life of the 

 fruit through its ripening effect. However, most trials with Mcin- 

 tosh have indicated that increased redness from ethephon is accom- 

 panied by stimulated ripening and softening. Nevertheless, the pos- 

 sibility remained that by using very low ethephon concentrations 

 combined with Alar*, red color might be enhanced without significant 



losses of storage life at least for relatively short storage 



times . 



To obtain a clearer picture of the effect of low ethephon con- 

 centrations on Mcintosh, last year a regional experiment was direc- 

 ted by Dr. G.D. Blanpied at Cornell University. The experiment in- 

 cluded orchards in western and central New York (^Br . Blanpied), 

 eastern New York (Dr. C.G. Forshey) , Maine (Dr. W.G. Stiles, and 

 Massachusetts. Ethephon was applied at 75 or 150 ppm (1/4 or 1/2 

 pint/100 gal) 2 weeks before the anticipated middle of the harvest 

 season, in combination with 1000 ppm (1 lb/100 gal) Alar* 2 months 

 before harvest plus a stop-drop spray of either 10 ppm 2,4,5-TP or 

 20 ppm NAA. (The stop-drop is necessary to counteract the dropping 

 action of ethephon.) Harvested fruits were stored in both regular 

 and CA storage and evaluated for both red color and firmness. In 

 addition, taste panels were asked to distinguish preference or ripe- 

 ness among the treatments after they had been at room temperature 

 for a week, to see if the treatments would influence marketability 

 of the apples. 



The results of the experiment showed that ethephon, whether at 

 75 or 150 ppm and whether combined with NAA or 2,4,5-TP, increased 

 the red color of the fruit. Thus, low concentrations of ethephon 

 are capable of improving red color of Mcintosh throughout the North- 

 east. (See also the article on ethephon use in July-August, 1974, 

 Fruit Notes . ) 



Did ethephon at these concentrations stimulate fruit softening? 

 Some small differences were measurable, especially with 150 ppm. 

 Apples that received this dosage were slightly softer than ones that 

 had not received ethephon when they were taken from regular storage 

 in November, and when they were taken from CA in the spring. How- 

 ever, differences were very small. In addition, apples that re- 

 ceived only 75 ppm ethephon plus 20 ppm NAA were slightly softer 

 than apples that received only Alar* when fruit were taken from CA 

 in the spring. 



What effect did the treatments have on marketability? Taste 

 panels had an extremely difficult time trying to determine prefer- 



*Trade name 



