24 MASS. EXPERIMENT STATION BULLETIN 305 



Weather Observations. (H. J. Franklin.) Further records bearing on frost 

 forecasting were made for the Station by observers at East Wareham, North 

 Harwich, East Gloucester, Carlisle, Fitchburg, Worcester, and Holliston. These 

 records and those of previous years were studied intensively, and the formulae 

 for predicting minimum bog temperatures were carefully revised to accord with 

 them. 



COOPERATIVE CRANBERRY INVESTIGATIONS 



Conducted by the Bureau of Plant Industry, United States Department of Agri- 

 culture, in cooperation with the Massachusetts Agricultural Experiment Station. 

 H. F. Bergman, Senior Pathologist, U. S. D. A., in Charge. 



Development of Strains of Cranberry Resistant to False Blossom. (H. F. 



Bergman, W. E. Truran, and Jos. L. Kelley.) Selected wild vines collected in 

 Maine in 1932 were set out on the State Bog. Most of the vines made good 

 growth and will be ready for propagation in 1934. Seedlings have been grown 

 from seeds of fruit from naturally pollinated flowers of the Early Black, Howes, 

 and McFarlin varieties to determine whether or not variations in the resistance 

 to false blossom will be found in seedlings segregating out in the progeny. Seeds 

 from reciprocal crosses of Early Black and McFarlin made in 1932 were planted, 

 but none of the seeds germinated. 



Oxygen Content of Flooding Water in Relation to Injury to Cranberry Vines. 



(H. F. Bergman and W. E. Truran.) Further experiments were made to deter- 

 mine the effect of the absence of oxygen in winter-flooding water on the develop- 

 ment of terminal and fruiting buds during the following season. They indicate 

 that low oxygen content in the winter-flooding water causes a retardation of 

 development of terminal buds and, when oxygen content approaches complete 

 absence, many of the terminal buds are killed. Flower buds of Early Blacks 

 and Howes on the State Bog and some other nearby bogs were tagged and their 

 development was followed throughout the growing season. Counts of fruit set 

 from these buds indicate, as in last year's counts, that on the basis of the total 

 number of fruits set from the total number of uprights examined, with one ex- 

 ception, more fruits were set from large or medium sized terminal buds than from 

 small ones. The exception was found in one section of Howes on the State Bog 

 where the winter flood was shallow. Here 48.3 per cent of the flower buds from 

 small terminal buds set fruit as against 42.9 per cent for the medium and 41 per 

 cent for flowers from large terminal buds. In deeper water on the same section 

 the fruit set from flowers from large terminal buds was 41 .2 per cent ; from medium, 

 35.8 per cent; and from small ones, 31.8 per cent. These variations have not 

 been correlated with oxygen content of the winter-flooding water. 



Regeneration of False Blossom Bogs. (H. F. Bergman and Jos. L. Kelley.) 

 Commercial weed killer (sodium arsenite) was applied to only one bog during the 

 past season. The weed killer was applied on two plots: on one at the rate of 800 

 gallons per acre; and on the other, 1000 gallons per acre. The higher rates of 

 application appeared to be more satisfactory than lower ones. 



Experiments were started on another bog to determine the effect of heavy 

 sanding, and of heavy sanding plus use of fertilizer, on the reduction of the 

 amount of false blossom. 



Vines of the Howes variety on these experimental plots showed a marked im- 

 provement both with sanding alone and with sanding and subsequent fertiliza- 

 tion, as compared with untreated areas. 



