HOWARD AND HOWARD. 43 



characters of which have been studied adequately. In the present 

 state of knowledge, this is undoubtedly the best material available 

 for the purpose and, consequently, the preservation of the pure lines 

 for the benefit of future workers becomes an important matter. 

 This is particularly so in countries like India where reliable seed 

 merchants do not exist, and where it is practically impossible to pro- 

 cure varieties of crops even botanically pure. Before hybridization 

 work can be begun in India, it is necessary to make surveys of the 

 particular crops studied and to separate them not only into botanical 

 varieties and finally into pure lines but also to determine with 

 precision all the characters of the pure lines themselves. All this 

 preliminary work necessarily involves the expenditure of considerable 

 time and money. As hybridization work proceeds more and more, 

 pure lines of known gametic constitution will become, as it were, 

 accumulated at the various stations, and the proper preservation of 

 this material is an important matter, and becomes a valuable asset 

 of the xlgricultural Department concerned. It is important that 

 it should not be lost and that it should be readily available 

 for future workers in a manner somewhat similar to the way in 

 which, at research centres, libraries of books are handed down to 

 posterity. 



The preservation and exchange of pure lines, the gametic 

 constitution of which has been proved, might easily become of very 

 general importance. There is little doubt that hybridization work 

 will, in the future, become in each country more and more restricted 

 to a few centres, and it is very probable that the material of one 

 country may be of use to the workers at centres in other countries. 

 Thus there may very easily be useful exchanges of pure lines in 

 Northern Europe and again in North America. The whole subject 

 of the best means of preserving pure lines of economic plants of 

 known gametic constitution is one which might well be taken 

 up by the next International Conference on Genetics or by the 

 International Association of Botanists. 



II. Plant Breeding Stations. 



The complexity of such apparently simple characters in wheat 



