. Cyclopedia of farm crops : a popular survey of crops and crop-making methods in the United States and Canada. Agriculture -- Canada; Agriculture -- United States; Farm produce -- Canada; Farm produce -- United States. G2 SOME OF THE PRIXCirLES OF PLANT-BREEDING selection has been discontinued, and indeed this is practically the only real criterion as to whether a new race has been produced. For example, in the case of the corn mentioned above as selected by De Vries. that in seven years had been increased from 12 to 20 in the number of rows to the ear, De Vries found that it required only ab
. Cyclopedia of farm crops : a popular survey of crops and crop-making methods in the United States and Canada. Agriculture -- Canada; Agriculture -- United States; Farm produce -- Canada; Farm produce -- United States. G2 SOME OF THE PRIXCirLES OF PLANT-BREEDING selection has been discontinued, and indeed this is practically the only real criterion as to whether a new race has been produced. For example, in the case of the corn mentioned above as selected by De Vries. that in seven years had been increased from 12 to 20 in the number of rows to the ear, De Vries found that it required only about three years of cul- tivation without selection to fall again to the original aver- age of 12 to 16 rows. In a case like this it would seem, therefore, that no distinctly new character had been added as a result of selection, but that the average of the race had been increased by the continuous selection under isolation, and that when the different individuals were al- lowed to breed together freely, without selection, the mean of the race, as a whole, was again quickly reestablished. Systematic methods of selection, or pedigree breeding. Two distinct methods of selection are in use, which are termed (1) the nursery method, and (2) the field method. The nursery method, which was used first by Hallet about 1868, so far as the writer is informed, consists in cultivating each plant under the most favorable conditions possible for its best development. By this method, with wheat, for example, Hallet pursued the policy of planting the individuals in squares a foot apart, which would give the plant abundant opportunity. ii^l^^'f"' m^ Fig. 82. Centgeners of flax. Plats ou lijiht bred for seed produptioii. thus short and very fruitful. Plats ou left bred for fiber production, thus tall and less fruitful. (Xotice difference in height is shown by difference in height of man's hand.) for stooling, and also enable the investigator to ^h clearly each individual plant. In
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