References
- Anon. 1980 . Seed Regulations, Amendments . Canada Gazette Part II. , 114 : 2433 – 2435 .
- Anon . 1987 . Council directives 77/93/EEC in respect of seed potatoes originating in Canada , 5680/V1/87-ENRev Brussels, , Belgium : Commission of the European Communities .
- Branch , A. D. , Benenfeld , B. J. , Franck , E. R. , Shaw , J. F. , Varban , M. L. , Willis , K. K. , Rosen , D. L. and Robertson , H. D. 1988 . Interference between coinoculated viroids . Virology , 163 : 538 – 546 .
- van Gelder , W. M. J. and Treur , A. 1982 . Testing of imported potato genotypes for potato spindle tuber viroid with a tomato-intermediate/electrophoresis combined method . EPPO Bull. , 12 : 297 – 305 .
- Grasmick , M. E. and Slack , S. A. 1985 . Symptom expression enhanced and low concentrations of potato spindle tuber viroid amplified in tomato with high light intensity and temperature . Plant Dis. , 69 : 49 – 51 .
- Jones , E. D. 1988 . A current assessment of in vitro culture and other rapid multiplication methods in North America and Europe . Am. Potato J. , 65 : 209 – 220 .
- Khoury , J. , Singh , R. P. , Boucher , A. and Coombs , D. H. 1988 . Concentration and distribution of mild and severe strains of potato spindle tuber viroid in cross-protected tomato plants . Phytopathology , 78 : 1331 – 1336 .
- McDonald , J. G. 1987 . Comparative levels of potato viruses S and Y infection of microplants and tuber propagated plants in the field . Am. Potato J. , 64 : 517 – 521 .
- Ostle , B. 1954 . Statistics in Research , The Iowa State College Press .
- Palukaitis , P. and Symons , R. H. 1980 . Purification and characterization of the circular and linear forms of chrysanthemum stunt viroid . J. Gen. Virol. , 46 : 477 – 489 .
- Palukaitis , P. and Zaitlin , M. 1987 . The nature and biological significance of linear potato spindle tuber viroid molecules . Virology , 157 : 199 – 210 .
- Singh , R. P. “ Occurrence, diagnosis and eradication of the potato spindle tuber viroid from Canada ” . In Viroids of Plants and Their Detection. Intl. Seminar , 1986 37 – 50 . Warsaw, , Poland 1988
- Singh , R. P. and Boucher , A. 1987 . Electrophoretic separation of a severe from mild strains of potato spindle tuber viroid . Phytopathology , 77 : 1588 – 1591 .
- Singh , R. P. and Boucher , A. 1988 . Comparative detection of mild strains of potato spindle tuber viroid from dormant potato tubers by return-polyacrylamide gel electrophoresis and nucleic acid hybridization . Potato Res. , 31 : 159 – 166 .
- Yoshikawa , N. and Takahashi , T. 1982 . Purification of hop stunt viroid . Ann. Phytopath. Soc. Japan , 48 : 182 – 191 .