ANNUAL REPORT, 1941 67 



DEPARTMENT OF FLORICULTURE 

 Clark L. Thayer in Charge 



Breeding Snapdragons for Varietal Improvement and Disease Resistance. 



(Harold E. White, Waltham.) Plants propagated vegetatively from Field Station 

 rust-resistant strains of commercial hybrid snapdragons have been tested two 

 summers under field conditions and in the greenhouse for two winters. These 

 strains were highly resistant to rust disease; a wide range of flower colors was 

 present, and growth and flowering habit were excellent. Many of these hybrids 

 are still segregating for rust susceptibility and are heterozygous for flower color. 



A few selections from seeded lines look promising as material for developing 

 pure breeding forms for rust resistance and desirable flower colors. In earlier 

 breeding work with Main's hybrids considerable difficulty was experienced in 

 getting rust resistance bred into such selections and at the same time retaining 

 desirable flower colors, growth habits, and blooming period in the same strains. 

 It was anticipated that with the commercial variety hybrids this combination 

 might be more readily developed into desirable pure-bred lines. 



These hybrids are available now, provided florists are interested in growing 

 snapdragons by propagating such strains from cuttings. 



Cultural Requirements of Freesia. (Harold E. White, Waltham.) Records 

 on the pre-curing or drying of freesia corms (% to % inch size), for a period of 

 3 to 11 weeks prior to planting, show that by this treatment in 1939 corms lost 

 from 3 to 24 percent of their weight; in 1940, 3 to 20 percent; and in 1941, 7 to 

 21 percent. Corms of Golden Daffodil (5^ to 5€ inch) in the 1940 treatment 

 failed to sprout unless pre-cured for 3 weeks prior to planting. Corms of this 

 variety received the same pre-curing treatment in 1941 but responded normally, 

 which would indicate that, although the pre-curing treatments of the corms in 

 1940 overcame the growth inhibition factor, this same peculiarity was not present 

 in the 1941 stock. 



Loss in moisture content of freesia corms through pre-curing treatments has 

 not been found to have any significant effect on the blooming or production 

 characteristics of the corms. At a temperature of 48°-50° F., corms grown in 

 benches flowered a week to ten days earlier than those grown in bulb pans. Early 

 and later planted corms in bulb pans, shifted in November from a temperature 

 of 50° F. to 60°F., flowered two weeks earlier on an average than those continued 

 at the cooler temperature. 



Results of tests in pre-curing freesia corms for periods of 2 to 11 weeks prior to 

 forcing indicate that such treatments are not essential for successful forcing 

 of freesias in the greenhouse. It is concluded that seasonal and cultural treat- 

 ments given the freesia corms in the field are more likely to determine their 

 forcing performance. 



The use of well-rotted manure in soil mixtures for freesias has not had any 

 harmful effect on the growth or flowering of the corms. 



Foliage tip-burn of freesia plants may be caused by fumigants and by fluctua- 

 tions in temperature, soil moisture, and humidity. Contrary to general opinion, 

 freesias will take plenty of water when well rooted in properly drained soil and 

 growing normally. 



Elder's Giant White was observed to be a much slower growing type than 

 Purity, Golden W'onder, or Golden Daffodil. 



Soilless Culture of Florists' Crops. (Harold E. White, Waltham.) This system 

 of plant culture has been conducted primarily as a demonstration for growers 

 and to determine how much attention must be given to such a system to obtain 

 crop production comparable to results from soil culture. 



