OLD TYPES AND NEW 203 



field where there is little crowding, but from situations 

 where the environmental conditions are ordinary or 

 even unfavorable. Individuals making a good showing 

 under such usual, or even adverse, conditions are wor- 

 thy by nature rather than by nurture and are conse- 

 quently most desirable as progenitors of future stock. 

 By this method the attempt is not to keep the progeny 

 of single individuals separate, but to mass together 

 the best as they appear under ordinary normal environ- 

 ment. 



This again is an indirect method of procedure, 

 although the character of the germplasm is more 

 nearly hit upon in this way than by Hallet's method, 

 since the mask of temporary accessory modifications/ 

 is stripped so far as possible from the somatoplasm, \ 

 and the phenotype made to approximate the geno-/ 

 typical constitution. 



B. PEDIGREE BREEDING 



Mass selection, or the choosing of a number of indi- 

 viduals out of a population to be the progenitors of 

 the next generation, is subject to repeated backsliding 

 to mediocrity and consequently the selection must be 

 made over and over again in each generation. A 

 greater degree of success than is possible by this 

 method has followed attempts to isolate single self- 

 fertilizing individuals that manifest the desired quali- 

 ties and to establish pedigrees from this isolated stock. 

 This is Johannsen's method of the pure line and is 

 particularly applicable to self-fertilizing plants, al- 



