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. S. 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. S. 

 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 



