64 MASS. EXPERIMENT STATION BULLETIN 339 



Apple tree leaves 27 Lime compounds 1 



Apple spray residue 32 Miscellaneous 3 



Blueberries 3 Nicotine solutions 4 



"D" deficient diets 7 Poultry manure 41 



Fertilizers 24 Synthetic manures 7 



Field crops 1 60 Sewage sludge 3 



Gardenia stems 2 Turnips 4 



Gardenia leaves 2 Weed exterminators 4 



Insecticide solutions 4 



Total 328 



Other chemical work of the department has included service to community 

 organizations, State institutions, and individuals interested in agriculture. This 

 group includes the following materials: 



Animal tissues for mineral poison. . . 5 Lime products 6 



Apple spray residue 5 Miscellaneous 2 



Ashes of various kinds 3 Peat products 9 



Compost 2 Sheep manure 7 



Fertilizers and fertilizer chemicals . . 26 Sheep manure and wool waste 10 



Insecticides 2 Soils 13 



Industrial by-products 8 



Total 98 



Research work in cooperation with the Association of Official Agricultural 

 Chemists of North America has included methods for the determination of 

 soluble and available magnesium in mixed fertilizers and the determination of 

 the acidity and alkalinity of mixed fertilizers. Services of an executive and 

 advisory nature have also been rendered to this organization as in the past. 



DEPARTMENT OF FLORICULTURE 

 Clark L. Thayer in Charge 



Breeding Snapdragons for Varietal Improvement and Disease Re- 

 sistance. (Harold E. White, Waltham.) Rust-resistant varieties of snap- 

 dragons sold by various seed firms showed a relatively high degree of resistance 

 to rust under greenhouse and field tests at Waltham. The Field Station rust- 

 resistant strains continued to show satisfactory performance under greenhouse 

 and field conditions. The resistant yellow-flowered strain tested by several 

 commercial growers under glass last year proved so satisfactory that requests 

 for more seed were granted to those growers who wished to make further trials. 



Field Station strains crossed with the resistant commercial varieties yielded 

 progeny carrying a high degree of resistance to rust. No physiologic strains 

 of the rust Puccinia antirrhini have been observed at Waltham. Field Station 

 resistant strains were inoculated with cultural rust material obtained from 

 California but there was no evidence of infection whereas commercial varieties, 

 inoculated with the rust, became infected. 



Data on the susceptibility of inbred and hybridized strains to Verticillium 

 wilt in the field indicate that a double type of resistance to rust and wilt may be 

 eventually obtained. Commercial varieties were 100 percent susceptible to wilt 

 as compared to 20 to 80 percent resistance in the case of hybridized strains. 

 Those strains that are most susceptible to rust appear to be less resistant to 

 Verticillium wilt. 



Study of the Effect of Plant Nutrients, Soil Reaction, and Light on 

 Gardenias. (Harold E. White, Waltham.) Chlorosis of gardenias, which 



