ANNUAL REPORT, 1933 41 



Agricultural lime products. ... 9 Manures, pulverized 3 



Ashes, cotton hull and inciner- Manufacturers' by-products 1 1 



ator 4 Miscellaneous 3 



Complete fertilizers 32 Peat products 14 



Fertilizer chemicals and un- Stomach contents for min- 



mixed materials 14 eral poisons 3 



Insecticides and fungicides. ... 4 Soils 52 



As in the past, contact and cooperation have been maintained with the Asso- 

 ciation of Official Agricultural Chemists of North America. 



DEPARTMENT OF FLORICULTURE 



Clark L. Thayer in Charge 



Breeding Snapdragons for Varietal Improvement and Disease Resistance. 



(Harold E. White, Waltham.) The stud>- of rust resistance in snapdragons has 

 progressed to the F3 generation. Succeeding generations have resulted in re- 

 duction in hybrid vigor due to continued inbreeding. This has been manifested 

 by a decrease in size of individual flowers and height of plants. Resistance to 

 rust in the different strains in the F3 generation has varied from 75 to 90 per 

 cent, and in one strain to 100 per cent. In most strains yellow and white colors 

 have bred 100 per cent pure in the F3 generation. Resistant plants from the F^ 

 generation ha\"e maintained their resistance, even under field conditions, for 

 three years. 



Resistance in all cases observed appears to be complete, with practically no 

 partial resistance. It would appear from data collected that resistance may 

 be linked to some factor since there is a tendency for resistance and white color to . 

 stay together a greater number of times than resistance with yellow. Further 

 study will be necessary to prove definitely any color linkage for resistance. A 

 brief paper on this work was presented at the meetings of the American Society 

 for Horticultural Science in 1933. 



Study of the Effect of Plant Nutrients on Carnations Under Glass. (Harold 

 E. White, Waltham.) When calurea, Cal-Nitro, ammonium sulfate, urea, 

 calcium nitrate, and sodium nitrate were used as nitrogen sources, using a 4-12-4 

 as a basic fertilizer, the calurea and Cal-Nitro plots ranked first in production 

 over the other materials. This rating has been observed for two years on ex- 

 perimental plots. Such results under experimental conditions would indicate 

 that a combination of ammonia and nitrate nitrogen is preferable to straight 

 nitrate sources. 



Plots receiving no phosphorus produced six less flowers per square foot, whereas 

 those receiving no potash produced eight less flowers per square foot. Plots 

 receiving all the fertilizer elements as a complete fertilizer produced only two 

 flowers less per square foot than plots receiving all the potash and phosphate 

 prior to planting. Experimentally the difference is not great, but from a com- 

 mercial standpoint it might be significant. 



W'hen bone meal was used as a source of phosphorus in comparison with super- 

 phosphate, the production was lowered six flowers per square foot. Nitrophoska, 

 used as a partial source of phosphorus in combination with superphosphate, 

 resulted in no great difference. 



Fertilizer studies with roses have been discontinued due to lack of greenhouse 

 space in which to grow this crop properly. 



