68 MASS. EXPERIMENT STATION BULLETIN 388 



Carnation plants have responded equally well to some four to six nutrient 

 formulas which have been tested. It is apparent, at least with carnations, that a 

 considerable degree of adaptability to nutritional levels exists under soilless 

 culture conditions, which is likewise true for plants grown in soil. 



Root rot and stem diseases of carnations can be just as prevalent and destruc- 

 tive under gravel culture methods as in soil, particularly soon after the plants are 

 set. Much of the danger lies in keeping the plants too wet rather than too dry. 

 Tobacco and naphthalene fumigants can be used on carnations in gravel, follow- 

 ing the same precautions necessary for successful fumigation of plants in soil. 



New England growers have shown little inclination to grow flower crops in 

 gravel, even on a trial basis. One grower, who last year was favorably impressed 

 with the results from 350 square feet of soilless roses, has expanded to 2,500 

 square feet. At Waltham cinders, which for two years were used in growing roses, 

 are now being used for the culture of carnations. 



Liming Carnation Soils. (Harold E. White, Waltham.) Data for two years 

 on the use of lime on carnation soils to determine the importance of soil acidity 

 as related to plant growth and flower production show that carnations have a 

 wide degree of adaptability to changes in soil acidity. The average acidity test 

 of soil used for carnations was pH 5.6; the final acidity readings over a period 

 of two years were 4.7 for unlimed and 6.4 for highly limed soils. While this 

 test does not cover extreme ranges in acidity or alkalinity, it does pertain to normal 

 variations of growers' soils as observed from soil testing records of five years at 

 the Waltham Field Station. 



There were no significant differences in flower production, number of split 

 calyces, or vegetative plant growth between plants in unlimed soil and those in 

 soil receiving applications of lime at the rate of 1 to 3 tons per acre. 



Plants of the variety Ward were used in these tests and the same cultural 

 treatments were given both years. Cultural and seasonal climatic conditions 

 were of greater importance than soil treatments in their effect on crop produc- 

 tion. The greater incidence of split calyces occurred between the months of 

 January and April. During the season of 1940-41 plants produced only 2 percent 

 more split calyces than during the previous season. 



Field-grown plants produced four more flowers per square foot of bench area 

 than greenhouse-grown plants. Since liming of soils had no perceptible effect 

 on prevalence of root or stem rot diseases, the common practice of applying 

 lime to correct or inhibit the spread of these soil organisms may be considered of 

 little value for the purpose. 



Disease Resistance and Heredity of Carnations. (Harold E. White, Waltham.) 

 This work is merely getting under way. Thirty-five varieties have been assembled 

 for study. The selfing of different varieties and experiments in germination of 

 pollen are in progress. 



In some preliminary breeding work in 1939-1940 a cross between the varieties 

 Ward (pink) and Puritan (white) gave a progeny of 45.83 percent white flowers, 

 36.45 percent pink, 2 percent red, and 15.62 percent variegated flowers. The 

 flower types were 8.24 percent singles, 56.70 percent commercial (normal) doubles, 

 and 35.05 percent bursters or split calyx types. Short-calyx flowers were dom- 

 inant over long or intermediate types. Broad-leaved characters of plants were 

 dominant over narrow and medium leaf characters. These observations show, 

 as was expected, that the commercial types of carnations are heterozygous for 

 many of the plant characters to be studied in this project. 



Coffee Chaff as a Soil Amendment. (Harold E. White, Waltham.) Inquiries 

 are frequently received from manufacturing concerns as to the possible use in 



