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Research Note - Original Series, 1930-1962
Title: Pine pollen collections dates - annual and geographic variation
Author: Duffield, J. W.
Source: Res. Note 85. Berkeley, CA: U.S. Department of Agriculture, Forest Service, California Forest and Range Experiment Station. 9 p.
Station ID: RN-PSW-085
Description: Activity in pine breeding has increased throughout the temperate forest regions of the world since the Institute of Forest Genetics issued its first summary of pollen collection dates in 1947. Cooperation between pine breeders has increased at the same time. The information most essential for conducting cooperative breeding operations are the dates of pollen collection (which also approximate the dates at which the bagging of flower buds to control pollination should be done) for various species at various localities. This publication, adding four years' data to the note issued in 1947, covers a period of 14 years. In addition, some data are presented on the relation between temperature and development of catkins and on the effect of altitude on time of pollen collection. These new data, although still fragmentary, should assist workers elsewhere to generalize from the data collected at the Institute of Forest Genetics.
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Duffield, J. W. 1953. Pine pollen collections dates - annual and geographic variation. Res. Note 85. Berkeley, CA: U.S. Department of Agriculture, Forest Service, California Forest and Range Experiment Station. 9 p.