154 



Similar experiments at Vesteras, about 70 miles west of Stockholm, were 

 still more in favor of the native sorts. These and other experiments have 

 demonstrated that Silesian clover is the only foreign sort which may be 

 imported into Sweden with safety, and this only in the southern provinces. 



A matter of importance in clover is the production of second growth or 

 "aftermath." The Swedish sorts are from two to three weeks later than 

 the imported sorts and the aftermath is consequently considerably smaller. 

 In total crop, however, the former sorts are found to excel the latter by a 

 substantial margin. Because of their lateness the Swedish sorts are also 

 more suitable for mixing with Timothy as they ripen at about the same time 

 as that crop. The early sorts, on the other hand, are ripe before the Timothy 

 is in best condition for cutting. 



Late Red Clover may be distinguished from the early strains not only 

 by time of ripening but by certain morphological characters. It is taller, 

 more branching, greener in color with a smaller percentage of heads placed 

 near the top of the plant. Late clover is also said to be longer lived than is 

 the Early while on colder, poorer soils which are not too dry it is found to 

 thrive better than the latter. The greater hardiness of Late Clover, as 

 already mentioned, is perhaps its greatest virtue, although it has also shown 

 itself able to resist certain diseases, notably clover-rot (Sclerotinia Trifoliorum, 

 Erikss.) (36, p. 158). 



A good deal of The Swedish clover has become mixed with the more 

 delicate foreign sorts which have been introduced through the trade, and 

 is consequently of inferior value. Witte (81, p. 319) has found for example, 

 clovers of the early smooth (so-called Silesian) type and of the early hairy 

 (so-called American) type among different strains of Late Swedish. Even 

 among stocks which are regarded as being genuine Swedish, types have been 

 distinguished which reveal distinct differences in regard to productive power 

 and other practical qualities. 



In view of the above circumstances the work of the Association at Svalof 

 with clovers has for its object the production of hardy, uniform races of known 

 origin and purity and of approved value for cultivation in the different parts of 

 the country. Sorts which bloom about the same time and which are other- 

 wise suitable for growing together in mixtures are also being sought for. 

 Principles In the clover plant, cross-fertilization is obligatory, that is pollen from 



and Methods one individual i s necessary for the fertilization of another. Pollination is 

 ordinarily effected by bees which travel from plant to plant in search of 

 of Red Clover honey and carry the pollen with them. 



The fact that at least two different plants are required in the production 

 of seed renders it practically impossible to produce sorts which are absolutely 

 constant and uniform in character since each single plant may be said to 

 constitute a distinct strain. Crossings between different strains always give 

 a variable progeny. Experience at Svalof has shown however, that it is 

 possible to attain a sufficiently high degree of purity and constancy in clover 

 to meet all the important requirements of practice. 



In view of the inability to apply the pedigree culture system to this crop, 

 a system of mass-selection is commonly used. Thus in seeking for hardier 

 strains, seed is collected from plants which have come through the winter 



