II. 



THE DISCOVERY OF THE ELEMENTARY 



SPECIES OF AGRICULTURAL PLANTS 



BY HJALMAR NILSSON. 



A. DIFFERENT PRINCIPLES IN THE BREEDING OF 



CEREALS. 



From the beginning of civilization, the cereals have taken 

 a prominent place in human culture. No industry has been 

 so intimately connected with the interests of mankind, and 

 upon no other agricultural crop has progress been so largely 

 dependent. Long before the time of the ancient Egyptian 

 kings, of the Romans and of the lake-dwellings of central 

 Europe, the cereals yielded the principal nourishment in all 

 the countries of the world where civilization developed itself. 

 Solms-Laubach has pointed out that China and Egypt have 

 cultivated mainly the same species and sub-species of grains, 

 and that on this ground it must be conceded that their cul- 

 tures have had a common starting-point. Three or four 

 thousand years before Christ, the principal varieties must 

 have been known to mankind, and it may even be assumed 

 that the very first beginning of this culture is much older. 

 Its probable origin is the central part of Asia, since only this 

 region can have been its common source for the Chinese and 

 Egyptians. 



Having so deep a significance, the cereals must have been 

 given more attention and more care than any other crop. 

 According to some verses of Virgil, the Romans knew their 

 cultivated races to be far from pure and uniform. They 

 also knew that care had to be taken in the harvesting of the 

 grains destined for sowing, since otherwise the races would 

 surely deteriorate. Each year the best ears had to be selected 

 in order to keep the varieties pure from an overwhelming 



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