50 MASS. EXPERIMENT STATION BULLETIN 293 



nurseries actually examined and there can be no doubt that the number of mis- 

 named trees sold has l)een greatly reduced. 



The Genetic Composition of Peaches. (J. S. Bailey and A. P. French.) 

 Evidence has been obtained that in peaches there is Hnkage between the gene 

 controlling stone adhesion and the gene controlling flesh toughness, with about 

 8 per cent crossing over. The Champion variety has an albino lethal character 

 which acts as a simple Mendelian recessive. Among certain seedlings a new 

 combination of leaf characters has appeared. Some individuals have very wavy 

 leaves, deeply serrate margins, and globose glands. A paper on "The inheritance 

 of certain characters in the peach" which is to appear in the 1932 Report oj the 

 American Society for Horticultural Science, will discuss these observations in more 

 detail. 



The breeding work was continued in the spring of 1932. This work was planned 

 so as to give further information concerning the linkage relations between stone 

 adhesion and toughness of flesh. Favorable weather conditions prevailed during 

 the breeding season and a good crop of pits was obtained. 



The two orchards of seedling peaches planted in 1928 had to be removed in the 

 fall of 1932 because of a severe infection of peach yellows. 



As a result of the peach breeding work in 1931, about 300 seedling peach trees 

 are in the nursery ready to be set in the orchard in the spring of 1933. 



Testing Methods of Pruning. (J. K. Shaw.) One of the orchards involved 

 in this work has passed into the hands of a commercial grower for reasons pre- 

 viously mentioned. Some observation on the orchard may still be made. Work 

 in the other orchard is still continued with no change in the trend of results. 



Effect of Pruning Bearing Apple Trees. (J. K. Shaw and O. C. Roberts.) 

 This experiment in an old bearing orchard has continued as in earlier years, 

 comparison being made between heavy, light, and no pruning. Sizing and grad- 

 ing tests show in some cases better color and larger size in the apples from pruned 

 trees and occasionally less insect infestation and disease, but the difTerences 

 continue to be less than most fruit growers would expect. 



Observations have been extended to include certain Rhode Island Greening, 

 Wealthy, Ben Davis, and Mcintosh trees, 35 years old, some of which are 

 moderately pruned while others are left unpruned. 



Comparison of Cultivation and Sod in a Bearing Orchard. (J. K. 



Shaw.) The amount of nitrate of soda applied to the sod plots was increased 

 in the Spring of 1932 from 300 to 400 pounds per acre. There is some evidence 

 that this may have resulted in yields larger than they would have been w'ithout 

 this increase. Yet the plot in cultivation with nitrate continued to make a better 

 showing; this gives further evidence that the sod-nitrogen program will not, over 

 a period of years give maximum yields. The Mcintosh trees on the cultivated 

 nitrate-potash plot continue to yield better than those on the similar plot receiving 

 nitrate alone, while the Baklwin trees do not. The increase in Mcintosh is about 

 70 per cent, while the Baldwin trees have shown little or no increase. Further 

 evidence is needed before it is safe to conclude that Mcintosh has more definitely 

 a potash requirement than Baldwin ; yet it may be true. 



The younger orchard included in this project has passed out of our control as 

 previously stated. 



Comparison of Clover Sod and Grass in a Sod Mulch Orchard. (J. K. 



Shaw.) The fertilizer treatments were continued as in previous years. The 

 grass has been allowed to grow and the white clover has almost disappeared from 



