39 



From the above tables it will be seen that some of the most valuable 

 strains possess only medium sized kernels. This fact at once exposes the 

 danger, when dealing with an ordinary variety which may consist of large, 

 medium and small kernelled strains, of over-sorting or grading, that is re- 

 taining for seeding purposes only the very largest kernels. In such cases a 

 uniform sample of plump, medium sized kernels should be sought for. The 

 use of pure strains of course obviates this difficulty entirely and herein lies 

 one of the many advantages of such strains. 



In .selecting heads of grain by mass-selection from mixed races with a 

 view to increasing the yield the natural tendency is to select the largest. 

 This is shown to be an unsafe practice. As is size of kernel so is size of head 

 a sort-character. Certain pure lines of outstanding value have been found 

 to possess a relatively small head while many inferior strains are characterized 

 by strikingly large ones. In other words there seems to be no definite relation- 

 ship between size of head and yield. A few examples will suffice to show 

 this : In barley, Princess and Chevalier though high yielders, have relatively 

 small heads while Imperial and many other inferior sorts have heads of large 

 dimensions. In wheat, English Stand Up and Tystofte Small which are among 

 the most productive sorts, are noted for the relative smallness of the head. 

 The continued selection of extra large heads from a composite race which 

 happens to contain both large and small headed strains can therefore easily 

 prove an injury rather than a benefit. An excellent illustration is afforded 

 by Vestergaard, in his investigations with the common Prentice barley 

 (I.e. p. 106). Out of this variety there was isolated, among others, a certain 

 group representing 4 6% of the whole and which was characterized by long 

 coarse straw and large heads. A comparison between pure lines from this 

 group and from the mother variety is given below as follows: 



Size of head 

 vrs. yield. 



Dangers 

 associated 

 roith mass- 

 selection. 



A mass selection of heads from the long strawed, long headed group 

 would obviously lead to decreased yield in this case. 



The question of stooling or the developing of ' side shoots ' in cereal grains Stooling in 

 and its relationship to yield and quality has also been investigated. .As grain vrs. 

 most growers know the power to ' stool ' varies more or less with different ^ w and 

 sorts. Under certain circumstances this characteristic may be of consider- yua 

 able practical value. Thus where the stand is thin as a result either of thin 



