83 



The object of this particular crossing is to combine the hardiness of 

 Squarehead with the higher yield of Stand-Up. The latter sort being less 

 hardy, combinations may be expected which are incapable of withstanding 

 the rigors of a severe winter. Obviously it would be waste of time to work 

 with cultures which only await specially severe conditions to be entirely 

 destroyed. The method in question allows nature, with the help of man, to 

 gradually weed out the weaker combinations so that after a few generations 

 only tried and constant forms remain. It is now proposed to make line 

 selections on a large scale from the above population. Such selections from 

 a population of known parentage are regarded as much more hopeful than 

 where one must deal with an unknown quantity as in the case of common 

 varieties. In the autumn wheat crossing Grenadier X Cone the severe winter 

 of 1905 performed a selective influence among the hybrids by either entirely 

 destroying the less hardy or by revealing their weaknesses so that a mass- 

 selection of strong hardy individuals could be made. While the above system 

 requires a considerable length of time before any definite results can be 

 reached, yet it requires very little work until the time comes to make selec- 

 tions. Numerous crossings of this kind may therefore be carried forward 

 with the regular work and thus provide a constant source of new material. 



In discussing the present status of the place of cross-breeding in cereal 

 improvement work Fruwirth (12) combines the conclusions of Nilsson-Ehle 

 and Tedin of Svalof with that of Tschermak and others thus : " That this 

 branch shall leave rich returns can no longer be doubted". 



Mass-selection, and the high state of development to which it attained Mass-selec- 

 at Svalof during the early years of the existence of that Institution, has twn - 

 already been explained in detail (See page 18). While this system was 

 doomed to occupy a secondary place in advanced breeding work and while 

 there are doubtless certain dangers associated with such a system, yet there 

 are good scientific as well as practical reasons why this method can still be 

 of service. In the first place a mass-selected stock, containing as it may a 

 number of distinct biotypes of varying potentialities may be able to give 

 higher average returns over a series of years and under a variety of conditions , , 

 than a pedigree sort which constitutes a single biotype, requiring as it may must not ^ e 

 more exact conditions. While the advantages of pedigree sorts cannot be discarded too 

 denied, yet on no account is it advised that such sorts be allowed to displace hastily. 

 a mass-selected sort of recognized value until the two have been carefully 

 compared. 



Mass-selection has proven especially useful both after crossing and in 

 ordinary line-breeding work with autumn sown sorts. In both cases it has 

 served to assist nature in eliminating the delicate and in conserving the 

 hardy. The mass-selected Squarehead wheat sort, Svalof s' Renodlad (Selected) 

 Squarehead, stands as a monument to the usefulness of this system. 



As a forerunner of pedigree selection from old mixed varieties the value Mass-selec- 



of mass-selection is fully recognized. By reason of the inability to test more , , 



J J .... forerunner of 



than a few dozen pedigree cultures at the same time it is important that there pedigree 

 be included among them as few inferior ones as possible. Two or three years selection. 

 of mass-selection as a preparatory work, is believed to be capable of reducing 

 very materially, the chances of selecting many- such types. A good example 



