120 PLANT BREEDING IN SWEDEN 



As has already been remarked, the separated forms were from the beginning 

 constant. The crops before mentioned, wheat, oats, barley, peas and vetches, 

 which at the time of the adoption of the pedigree system had already been in» 

 vestigated, are typical self^fertilizers and the pedigree sorts are therefore pure lines. 

 That this constancy was perfectly permanent was not clear from the beginning. 

 Hoping that they could still be improved, the pedigree sorts of the above men* 

 tioned crops were also subjected to a repeated selection which, however, natu« 

 rally was without result. 



In oats and still more in wheat and seemingly also in vetches spontaneous cross 

 sings occasionally take place. This is also the case with common six^rowed barley 

 (Hordeum tetrasiichum). Even spontaneous variations (mutations) can arise. Accor* 

 ding to NilssonsEhle, for instance, who first observed the fact, wild^oat types 

 often, if not regularly, arise as a result of »loss«mutation» in originally constant 

 pedigree sorts of white oats. And when an originally constant pedigree sort 

 thus for one reason or other becomes ununiform it is naturally necessary to make 

 a new selection in order to regain the original form. 



The constancy of the types warrants that the advances which they represent will 

 be permanent. Thanks to this fact it will also be possible to form a far more accurate 

 opinion as to what conditions the different sorts require, than when dealing with mixed 

 sorts. These sorts can namely be changed hereditarily by external circumstances. Accor* 

 ding as the agricultural conditions change, now one and now another of the mixed 

 parts is favoured and increases in quantity at the cost of other parts. Thanks 

 to their constancy and uniformity the pedigree sorts are also easier to recognize 

 and consequently give greater possibilities for an effective control, a fact which is 

 a necessary condition in order to carry on a real and an honest trade with impro* 

 ved sorts. Nothing is gained by getting an improved sort which can not be 

 recognized but is easily mistaken for less valuable sorts. Both difficult and expen* 

 sive measures would at least have to be taken in this case in order to prevent 

 the latter being launched on the market under false flag. 



It must, as is easily understood, take several years before the first pedigree 

 sorts were ready for sale, but thereafter these were rapidly followed by like sorts, 

 a proof of the value of this method for plant breeding. Many of these sorts, 

 raised by line selection from old sorts are no longer cultivated, they having been 

 superseded by still better sorts, but many of them are still cultivated and success* 

 fully compete with the best sorts, produced during the last years. 



Thus it has been observed that the Segerhavre (Victory Oat, 1908) as well 

 as the Guldregnshavre (Golden Rain Oat, 1903), both white oat sorts and both des* 

 cending from the Milton Oat, a mixed sort of the Probsteier type, which is said to 

 come from America, have been difficult to surpass. (The numbers mentioned in the 

 parenthesis, both here and in the following, name the year, when each sort was put 

 forth on the market.) Of black oat sorts the Stormogulhavre (Great Mogul Oat, 

 1901) still gives the highest yield. This type as well as the Klockhavre (Bell Oat, 

 1901) is bred from the Black Tartarian Plume Oat. On account of its late maturity 

 the Great Mogul Oat has not, however, gained that importance within the black 

 oat districts, which are situated in Middle Sweden especially, which it otherwise 

 would have done. 



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