REDCORT: A SUPERIOR STRAIN OF CORTLAND 



Wesley R. Autio 



Department of Plant and Soil Sciences 



University of Massachusetts 



Apple growers are always looking for strains which have superior color 

 to the standard strains. Redcort (sold by Hilltop Orchard and Nurseries, 

 Inc., Hartford, Michigan) is one such Cortland strain. It was selected as a 

 branch mutation on a standard Cortland tree in Marlboro, NY. 



Redcort and Cortland trees on M7A rootstocks were planted in I98O at 

 the Horticultural Research Center, Belchertown, MA. In I985 fruit were har- 

 vested on September I6 and September 23 for evaluation. Measurement of the 

 internal ethylene concentration was used to determine differences with 

 respect to the time of ripening. As apples ripen the ethylene concentration 

 in the core rises sharply, providing a means of pinpointing the time of 

 ripening. Both the internal concentration at harvest and the number of days 

 after harvest required for the core ethylene concentration to reach 1 ppm 

 are reported in Table 1. As the fruit matures the number of days required 

 for the internal ethylene concentration to reach 1 ppm declines, so a more 

 mature fruit would have a higher internal concentration at harvest and would 

 require fewer days to reach 1 ppm. There were no differences between 

 Redcort and Cortland in these two measurements for the two harvests, so our 

 data suggest that Redcort and Cortland fruit ripen at the same time. 



Table 1. Ripening of Redcort and Cortland fruit in I985. 



*Within columns, means not followed by the same letter are significantly 

 different at the S% level. 



On September 23 fruit weight, diameter, firmness, and soluble solids 

 were also measured (Table 2), but no differences existed between the two 

 strains for any of these parameters. The percentage of the surface of the 

 fruit which was red also was assessed on September 23, and Redcort fruit 

 were significantly redder the Cortland fruit. Redcort fruit averaged 86% 

 red, whereas Cortland fruit averaged only 58^ red. Fruit from these trees 

 were placed in air and CA storage for evaluation of storability. 



