16 MASS. EXPERIMENT STATION BULLETIN 400 



A modified dominant type of resistance was produced in progeny from crosses 

 made between susceptible commercial varieties. 



Rust-resistant strains have been developed that have an inherited resistance 

 of 80 to 90 percent. Flower colors range from white to pink, yellow, and orange 

 yellow. These Field Station rust-resistant hybrids have a vigorous habit of 

 growth, are free flowering and suitable for winter bloom under glass. 



No inheritable differences in resistance to verticillium wilt, mildew, or anthrac- 

 nose were observed in the hybrids. 



Fifty-six wild species and strains of Antirrhinum were tested for their reaction 

 to rust. Species noted to be most resistant were: A. Charidemi Lge., A. calyciniini, 

 A. Ihanjezii Pau., A, sicjdum NCZ, and four strains of A. glutinosum. 



Definite progress has been made with the Field Station strains in combining 

 rust resistance with a desirable plant type and a winter flowering habit. Plants 

 propagated from cuttings have been resistant to rust for three seasons in field 

 and greenhouse tests. 



No physiologic races of the rust fungus were observed on the rust-resistant 

 hybrids tested. 



Literature Cited 



\. Blasdale, W. C. On a rust of the cultivated snapdragon. Jour. Mycol. 

 9:81-82. 1903. 



2. Blodgett, C. O., and Mehlquist, G. A. L. Snapdragon rust-resistance trials 



1937-38. Hilgardia 13:569-581. 1941. 



3. Doran, William L. Rust of Antirrhinum. Mass. Agr. Expt. Sta. Bui. 202: 



39-66. 1911. 



4. Emsweller, S. L., and Jones, H. A. The inheritance of resistance to rust in 



the snapdragon. Hilgardia 8:197-211. 1934. 



5. Hurd, Annie Maj-. Hydrogen-ion concentration and varietal resistance of 



wheat to stem rust and other diseases. Jour. Agr. Res. 23:373-386. 1923. 



6. Hursh, C. R. Morphological and physiological studies on the resistance of 



wheat to Puccinia graminis Tritici Erikss. and Henn. Jour. Agr. Res. 

 27:381-412. 1924. 



7. Lepik, E. Spread of snapdragon rust in Europe. Internatl. Bui. Plant 



Protec. (Roma) 15 (1941) :5, 93M, Fig. 1. 



8. Mains, E. B., and Jackson, H. S. Physiologic specialization in leaf rust of 



wheat, Puccini triticini Erikss. Phytopathology 16:89-120. 1926. 



9. Mains, E. B. Rust resistance in Antirrhinum. Phytopathology 25:977-991. 



1935. 



10. Peltier, George L. Snapdragon rust. 111. Agr. Expt. Sta. Bui. 221:535-548. 



1919. 



11. Peterson, R. F. Stomatal behavior in relation to the breeding of wheat for 



resistance in stem rust. Sci. Agr. 12:155-173. illus. N. 1913:3. 



12. Walker, J. C. Disease resistance in vegetable crops. Bot. Rev. 7:458:506. 



1941. 



13. White, Harold E. Preliminary report on breeding rust resistant snap- 



dragons. Proc. Amer. Soc. Hort. Sci. 30 (1933):589-590. 1934. 



14. Yarwood, C. E. Physiologic races of snapdragon rust. Phytopathology 



27:113-115. 1937. 



