One Seed Source of Jeffrey Pine Shows Resistance to Dwarf Mistletoe

摘要

Four seed sources of jeffrey pine (Pinus jeffreyi) were selected for testingthrough controlled inoculation for resistance to dwarf mistletoe (Arceuthobium). The pines were 7 years old and part of a progeny test planting established by the USDA Forest Services's Institute of Forest Genetics, Placerville, California. One of the seed sources (Foresthill) was considered from previous studies to be highly resistant. It was also found to be resistant in the study. Test trees were inoculated in 1980 and 1981 with about 13,5000 seeds of dwarf mistletoe. A high proportion of the seeds were lost before germination, but branches covered with bird-proof and insect-proof mesh lost significantly fewer seeds. Mean percentage infection based on remaining seeds was significantly lower on trees from the Foresthill seed source than any of the other sources.