ANNUAL REPORT, 1930 251 



characteristics and correlations received more attention during the year 

 than any other one line of investigation. It was found that the most 

 desirable varieties, as measured by productiveness and disease resistance., 

 seldom or never develop berries with more than four locules, while berries 

 Mith five or six locules are not uncommon among the fruit of many 

 inferior varieties. As a result of these studies with cranberry varieties, 

 the following conclusions have been reached: 



(1) Disease resistance is a unit. In other words, varieties that resist 

 one disease notably tend to resist other diseases well. 



(2) Disease resistance is an intimate co-function ivith productiveness. 



(3). The significance of the important correlations bearing on produc- 

 tiveness and disease resistance apparently mai/ he expressed by the foUoxcing 

 formula: 



P+R+M==T— AV 

 In tills formula, P is productiveness as measured by the number (not the 

 quantity) of berries produced to a unit of area, R is the amount of disease 

 resistance, M is the minimum of plant structure necessarj' for the fruit pro- 

 duction, T is the total result of the constructive work done by the vital ac- 

 tivities of tiie plants, and AV is the total of the \arietal wastes. The following 

 are the leading wastes so far noted and determined: 



(a) Seeds. Only a few small seeds are necessary. The more numerous 

 and the larger the seeds, the more they tax the plant economy needlessly. 



(b) ]Va.v. A bloom on the fruit is not essential, and its development 

 seems to l)e very costly to the vines. 



(c) Sugar. Much sugar in the berries is not essential. 



(d) Pectin. This has not been studied nuich yet, but it is likely to be 

 one of the wastes. 



(e) Excessive vine groit'th. as indicated by coarseness of the vines or tall- 

 ness of the uprights or both. 



As M in the above formula should be practically the same for all vari- 

 eties, the value of P+R necessarily varies directly with the value of T — W; 

 and since the accumulated records and observations of the actual per- 

 formance of diflPerent varieties indicates that the value of P+R is in- 

 versely and greatly dependent on the value of W, it seems probable that 

 T varies only moderately on the average. As will be seen, when the value 

 of T — W is low, P can have a high value only when the value of R is low 

 and vice versa. 



Through special assistance during the summer months, the photosynthesis 

 of several of the leading varieties was studied. Hydrogen-ion determina- 

 tions were made of the fruit of a large number of varieties and the pH 

 value was found to be about 2.6 with all varieties at all times during the 

 picking and storage season. 



Cultivated Blueberries. (H. J. Franklin). Fairly extensive counts of 

 the seeds of quite a number of cultivated blueberry varieties were made 

 and it was found that the most desirable varieties, as measured by the 

 quantity and size of berries produced, had notably fewer seeds than the 

 otiiers in nearlv all cases. 



