155 



and spring with least damage. This seed is sown on an isolated plot en-masse 

 and the progeny carefully studied. If the latter proves promising, a seed 

 crop is taken, part of the seed being preserved in its present state of purity 

 for a possible future use, the remainder being sown on a trial plot adjoining 

 others for comparison. 



In the choice of initial plants great care is exercised in seeing that these 

 are as nearly alike as possible in all important particulars. Were plants of 

 widely different character chosen as " mothers " the resulting progeny would 

 present a motley collection of types. Obviously, the fewer the number of 

 mother plants considered the more quickly will constancy be approached. 



When a sort has been carefully tested in comparative trial plots and in 

 the laboratory for a sufficient number of years and has shown itself worthy . , 

 of distribution, a multiplication is made of the original seed which has been SU p er ior 

 preserved during the intervening period. The necessity of using such seed types. 

 will be apparent when the dangers from crossing between plots which 

 adjoin each other are taken into consideration. 



Very little grass seed is grown in Sweden. Even Timothy seed which Grasses. 

 can be produced with comparative ease, is imported in large quantities (1^ 

 million pounds yearly) , a good deal of this seed coming from North America. 



Seed of Orchard Grass, Rye Grass and Tall Oat Grass is procured chiefly 

 from France, England, Australia and America. Meadow Fescue is obtained 

 for the most part, from North America although this seed is produced in a 



small way in many places throughout Denmark. 



^P 



In experiments at Svalof, Swedish-grown Timothy seed produced 15% 

 higher yield than that from North America despite the fact that the Swedish 

 material used in this comparison had not been specially selected. 



Orchard Grass seed imported from Denmark has been found to give 

 better results than that from Germany and especially that from Australia 

 while Meadow Fescue seed from Denmark has also proven superior to that 

 from other foreign sources. The differences in seed from different countries 

 is striking and demonstrates the need of special care when importing seed. 



In the prosecution of improvement work with grasses the principles to 



be observed are somewhat different from those recognized in the case of 



.... and Methods 

 clovers or of cereal grains. In the latter case each plant fertilizes itself, with 



comparatively rare exceptions. In grasses, on the other hand, the flowers grasses. 

 open before fertilization takes place, thus allowing the pollen to be carried 

 by the wind from flower to flower and from plant to plant. The result of 

 this peculiar arrangement is that while cross-fertilization is not obligatory 

 as in clover, yet a large proportion of the flowers become cross-fertilized and 

 consequently produce seed of hybrid character. Such seed when sown, 

 necessarily gives 'a mixed and variable progeny. Some plants of this progeny 

 may, if fertilized with their own pollen, breed true; others, (heterozygous 

 forms) will " split up " in any case. By reason of this fact there is to be found 



