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3. The use of defective methods of selecting the progeny of crossings, 

 the custom being to select on the basis of morphological characters only. 



As a result of this practice, a relatively small number of the possible 

 combinations were taken into consideration. Since heterozygous and homo- 

 zygous forms are often quite similar in appearance, and since individuals 

 of the same morphological aspect can be very different in physiological 

 characters, and thus be of very different practical value, all promising 

 individuals in the early generations of a crossing must be taken for separate 

 propagation and study. The significance of this method is evident, especially 

 when sorts which resemble each other closely in morphological characters are 

 crossed. When the principle of Mendelism became better understood, it was 

 quickly seen that the system of pedigree selection after artificial crossing is 

 even more necessary than is this method in ordinary line-breeding work 

 where only constant combinations are considered. Indeed, Mendel may be 

 said to be the real founder of the scientific principle of pedigree selection, 

 while Vilmorin was the first to apply it in practice. 



During the early years in which breeders sought to apply the Mendelian 

 principle, certain workers were led to believe that many crosses did not 

 display the Mendelian proportions, a fact which served to prevent the 

 universal acceptation of the law as such. Within more recent years, however, 

 students of heredity seem to have more clearly interpreted the fundamental 

 principles involved and have thus found a satisfactory explanation for many 

 of these apparant irregularities. 



Following the discovery of the numerous distinct and constant forms The necessity 

 which go to make up many of our old races, it was believed that artificial f s y stemaiic 

 crossing work as a means of producing further material would seldom be cr 

 required. Experience, however, seems to have taught otherwise. True, 

 progress has been made and superior sorts have been developed by taking 

 what nature already offered, but in a great many cases some of the most 

 promising of these sorts in regard to certain qualities have been conspicuously 

 weak in others. Thus selections for such specific characters as stiffness of 

 straw, rust resistance, winter-hardiness (in autumn sown crops) early, 

 maturing, high yield, etc., have been made from old varieties on an extensive 

 scale, and while an advance has been made in some cases, yet the problem 

 has not proven an easy one. It has, in fact, been found difficult to obtain 

 in old races, strains which combine the best of all qualities. A good example 

 is afforded in connection with an attempt to obtain a special winter hardy 

 strain of wheat from the Grenadier variety by carefully removing all the 

 weak and damaged plants from this variety after each severe winter. After 

 the hard winter of 1901, a selection was made of plants which had survived 

 the severe conditions of that memorable year. These plants were propagated 

 separately as pedigree cultures where practically all proved hardier than the 

 parent sort. The most promising of these cultures was multiplied and an 

 Elite stock handed over to the Swedish Seed Company in the Spring of 1903 

 for commercial exploitation. The summer of 1903 proved a very bad one for 

 rust, a circumstance which revealed the interesting though disappointing 

 fact that this new winter-hardy sort which previously had proven so promis- 



