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al. 1984, Tahvanainen et al. 1985, Clausen et al. 1986, Hansson et al. 1986, Snyder 1992). Although no specific stimulants
have been reported to be involved in differences in palatability between genotypes, the possibility that A4 has some specific
substance(s) that enhance browsing by hares has not been disproved. Our present results only suggest that volatile terpenes
and water-soluble sugars do not have a decisive effect on the differences in the palatability between A4 and other clones.
The A4 clone :isa genotype showing extremely high palatability compared to other plants of the same species. Other
elite clones originating in Atetsu (Atetsu 1, 3, 5, 6) do not show higher palatability than clones from other areas, hence the
palatability of A4 is difficult to attribute to its geographic origin (Kuwahata and Tanbara 1983). Although many studies
describe large palatability variation within a species, A4 still seems exceptional.
SUMMARY
We examined the chemical factors determining the extremely high palatability of a sugi clone, A4, to hares. The
palatability of A4 was fairly stable throughout the year. Although A4 had much less essential oil and dichloromethane
extracts than the other clones, steam distillation (or boiling) and extraction by n-hexane did not reduce the palatability.
Extraction by methanol made A4 unpalatable, whereas it seemed to make other unpalatable clones more palatable. Methanol
extracts of A4 had a stimulating effect on feeding whereas that of N4 had a deterrent effect. A4 might contain specific
feeding stimulants that are insoluble in n-hexane, soluble in methanol, and difficult to dissolve in water.
LITERATURE CITED
BRYANT, J.P. 1981. Phytochemical deterrence of snowshoe hare browsing by adventitious shoots of four Alaskan trees.
Science 213: 889-890.
BRYANT, J.P., WIELAND, G.D., REICHARDT, P.B., LEWIS, V.E., and MCCARTHY, M.C. 1983. Pinosylvin methyl
ether deters snowshoe hare feeding on green alder. Science 222: 1023-1025.
CHtBA, S., OGAWA, A., NAGATA, Y., and TOMAKI, K. 1991. Effects of solvent extracts on resistance of Japanese larch
and Kurile larch to voles. Proc. Hokkaido Branch, Japan Wood Res. Soc. 23:70-72 (in Japanese).
CLAUSEN, T.P., REICHARDT, P.B., and BRYANT, P.B. 1986. Pinosylvin and pinosylvin methyl ether as feeding deterrents
in green alder. J. Chem. Ecol. 12:2117-2131.
DIMOCK, E.J., SILEN, R.E., and ALLEN, V.E. 1976. Genetic resistance in Douglas-fir to damage by snowshoe hare and
black-tailed deer. For. Sci. 22: 106-121.
FARENTINOS, R.C., CAPRETTA, P.J., KEPNER, R.E., and LITTLEFIELD, V.M. 1981. Selective herbivory in tasseleared
squirrels: role of monoterpenes in ponderosa pines chosen as feeding trees. Science 213:1273-1275.
HANSSON, L., GREE R., LUNDREN, L., and THEANDER, O. 1986. Susceptibility to vole attacks due to bark phenols
and terpenes in Pinus contorta provenances introduced into Sweden. J. Chem. Ecol. 12: 1569-1578.
HARA, M. 1973. The variation of hare damage among sugi clones. Proc. Tree Breed. Soc. 63-66 (in Japanese).
HIRAKAWA, H. 1989. Screening of the preferential feeding substance(s) of the Japanese hare (Lepus brachyurus) included
in the Japanese cedar (Sugi, Cryptomeriajaponica). Proc. Kanto Branch, Jap. Soc. For. 41:145-147 (in Japanese).
KUWAHATA, T. and TANBARA, T. 1983. The variation of susceptibility to hare damage among sugi elite clones. Proc.
Kansai Branch, Jap. For. Soc. 34:213-216 (in Japanese)
MATSUURA, T: and MAEDA, M. 1981. Damage from red-backed vole (Clethrionomys rufocanus bedfordiae) to Saghalien
fir (Abies sachalinensis) varies with each strain. For. Tree Breed. Hokkaido 24:15-20 (in Japanese).
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