164 



Promising plants which have been isolated for testing in separate culture 

 are pulled up by the roots and divided in the manner indicated. All divisions 

 (sister plants) from the one mother plant may be planted in a plot by them- 

 selves, sufficient room being allowed between each to permit of their proper 

 development. The location of this plot should be such as to safe-guard the 

 plants from cross-fertilization by other sorts. 



Photo, bv L. H. N. 



FIG. LII. View from tower of main building Svalof, showing pedigree grass plots. 



During the following summer the material may be further increased by 

 continuing the splitting of the year-old plants, or if there already be sufficient 

 material, this may be subjected at once to a critical examination for varia- 

 tions. The seed produced from each of the plants on the above plot will be 

 the result of self-fertilization, providing the isolation from other sorts has 

 been adequate, since each plant came originally from the same root. The 

 progeny of this seed in two or three successive generations is likely however, 

 to show more or less variation just as in cereals which have been artificially 

 cross-fertilized. 



Where the variation is negligible and the strain as a whole has shown 

 itself superior, it may be multiplied for the trade. Where the variation is too 

 great on the other hand it is necessary to begin again from one of the single 

 plants and repeat the above process of root-splitting until sufficient constancy 

 is finally obtained. 



