300 GENETICS IN RELATION TO AGRICULTURE 
portant that the most promising forms which exist be secured, if possible, 
at the beginning of such projects. Some of the older collections of living 
plants, such as Arnold Arboretum and the New York, Brooklyn, and 
Missouri botanical gardens, as well as the Government Office of Seed and 
Plant Introduction, have given valuable assistance in supplying new and 
rare material to breeders. The transportation of pollen has also been 
resorted to, especially by the U. 8. Department of Agriculture in its 
breeding of Citrus and it is known that, with proper precautions, some 
kinds of pollen can be sent by mail half-way around the world and still 
be viable. However, certain much desired crosses can be secured only 
after repeated efforts and the trial of various methods. Moreover, the 
response of introduced forms to local conditions is a most important con- 
sideration. All too often a supposedly promising new plant has proven 
entirely unfit for certain localities. These considerations are leading to 
the establishment of large working collections of our more important 
semi-permanent crop plants, especially the tree fruits. For example, the 
University of California Citrus Experiment Station is accumulating a 
collection which will include all the known species and varieties of Citrus 
and allied genera which will endure local conditions. 
Research on Plant Groups—A breeding program such as that con- 
templated by the institution just mentioned involves the necessity of ex- 
tensive botanical investigations. In this particular instance it is fortu- 
nate that extensive work has already been accomplished by the U. 8. 
Department of Agriculture since already a large amount of data on the 
botanical relationships and geographical distribution of the members 
of the Citrus group has been collected. As a result of these studies and 
explorations several new and very promising forms have been introduced 
and have already been utilized in breeding experiments by the Bureau of 
Plant Industry. Similar investigations of the genus Prunus are also 
under way by the Department. The recent explorations of date growing 
countries and studies on the varieties of dates is another illustration of 
the sort of work that is needed, not only among fruits in general but in the 
field crops as well. 
Organization of Plant Breeders—In December, 1903, the American 
Breeders Association was organized under the auspices of the American 
Association of Agricultural Colleges and Experiment Stations. During 
the first seven years of its existence the publications of this organization 
were restricted to the annual reports of its meetings. These reports 
contain the papers which were presented at the meetings either in full or 
by title. In 1910 the Association undertook the publication of a quar- 
terly journal, the American Breeders Magazine, and discontinued the 
publication of annual reports. This magazine in January, 1914, became 
the Journal of Heredity, which is published monthly. At the same time 
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