ANNUAL REPORT, 1946-47 43 



milk inspection laboratories in the Commonwealth were visited at least once to 

 check apparatus and general conduct of the work. 



In addition to the regulatory work the Feed and Fertilizer Control laboratories 

 have examined feeds, fertilizers and other agricultural materials for citizens of 

 the Commonwealth without charge whenever the results were considered of 

 interest to the general public or to the Control Services. 



Considerable work has been done on research projects in cooperation with 

 other departments of the University and Experiment Station. The results oi 

 such work are reported by the departments originating the projects. 



DEPARTMENT OF FLORICULTURE 

 Clark L. Thayer in Charge 



Breeding Snapdragons for Variety Improvement and Disease Resistance. 



(Harold E. White, Waltham.) The variety Helen Tobin and a pink-flowered 

 inbred line P-41 intercrossed yielded progenj- that was 90 to 100 percent resistant 

 to rust under field conditions. Hybrid progeny from these crosses was more 

 vigorous than the parent lines and more uniform as to flower colors. The P-41 

 .ctrain is resistant to rust and transmits this character readily to rust-susceptible 

 varieties when crossed with them. 



A number of samples ot seed from the Field Station hybrids have been dis- 

 tributed to local growers. Several growers have reported that the hybrids are 

 an improvement over many of the commercial varieties and that cut blooms from 

 them have brought better monetary returns. 



Six of the Field Station hybrid lines were tested in Cali'o'nia where they did 

 not prove to be resistant to Form 2 of the snapdragon rust, even though they were 

 resistant to Form 1 which is prevalent in Waltham. , 



Strains of snapdragon from Waller Franklin Seed Company, Guadalupe, 

 California, were tested at Waltham and found to be highly resistant to the form 

 of rust present here. However, they are not as free flowering as the Field Station 

 strains. 



Subirrigation Methods of Watering Carnations. (Harold E. White, Waltham.) 

 Three different systems of applying water to subirrigated benches were studied : 

 constant water level with regulation by a float valve, manual injection, and auto- 

 matic injection. 



The automatic injection method was of two types, whereby (1) a solenoid 

 valve was operated through a relay and time clock, and (2) a solenoid valve was 

 controlled through a pneumatic and a pressuretrol control regulated by means of 

 a stoker timer. This pneumatic system was connected to an air pressure thermo- 

 static control unit used to operate the greenhouse heating sj'stem. Soils were 

 watered by manual and automatic injection systems when between 2 and 3 

 pounds vacuum pull in the soil showed on the tensiomete"- vacuum gauge. 



Investigation of the pneumatic system of automatic water injection is being 

 conducted through cooperation with the Minneapolis-Honej'well Regulator Com- 

 pany, Minneapolis, Minnesota. 



Varieties of carnations used in the tests were: Weld, Northland, Tom Knipe, 

 Hercules, Salmon Virginia, and Dark Pink Virginia. The soil, which had been 

 used for carnations the previous year, was sterilized with steam. 



