Wheat Investigations. 13 



Material and Methods. 



In undertaking the wheat improvement work at Aroostook 

 Farm in 191 5 the question arose as to what material should be 

 used as the source of improved wheat strains. A consideration 

 of the deterioration in the physical characteristics of the north- 

 western wheats under Aroostook conditions, and of the great 

 differences between the environment of Maine and the North- 

 west, at once suggested the advisability of confining the selection 

 work chiefly to the native Aroostook grown wheats or adjoining 

 regions. Since the quality of the wheat crop appears quite 

 susceptible to the influence of climatic factors it was thought 

 that the reaction, if any, of the different varieties and strains in 

 the course of many seasons to the environmental factors has 

 long become established in the form of a greater or less degree 

 of adaptation. Selection work on these varieties would result 

 in the isolation of the best adapted varieties or strains and in 

 the elimination of the poorly adapted ones, the degree of adap- 

 tation being measured by the maximum quality of any given 

 strain. 



The methods used in the wheat improvement work at 

 Aroostook are based on the principles of pure line selection and 

 hybridization. The present paper deals only with the results 

 of the selection work. For a detailed account of the method 

 of pure line selection and of the field technic as applied to small 

 grains by this Station the reader may be referred to a previous 

 paper. 18 We may only consider here a few features not men- 

 tioned in the paper just cited, which are peculiar to wheat. In 

 selecting wheat strains for quality a certain procedure of diag- 

 nostic value is required by means of which the relative quality 

 of the different individual plants may be determined. The yield 

 of grain from a single spike is obviously too small to be used 

 for a nitrogen analysis or even for a gluten determination by 

 the chewing test without interfering with the propagation of 

 the seed. The estimation of the quality of the grain from the 

 individual spikes following their isolation from commercial vari- 

 eties was based in this work upon the hardness, color, size and 



18 Frank M. Surface and Jacob Zinn. Studies on Oat Breeding IV. 

 Pure Line Varieties. Maine Agric. Exp. Station, Ann. Rept. 1916, pp. 

 97-148 (Bulletin No. 250). 



