. Cyclopedia of farm crops. Farm produce; Agriculture. SOIIE OF THE PRINCIPLES OF PLANT-BREEDING 59 The third type of variation which is of impor- tance to the plant - breeder is that produced by hybridization or crossing, and here we probably have the most prolific source of variations, and, therefore, the class of variation of the greatest importance and most consequence to the breedej It has come to be an established policy to combine the good qualities of two races into a single race by hybridization and selection. Iiijiuence of environment.— It is a well-known fact that environment has a
. Cyclopedia of farm crops. Farm produce; Agriculture. SOIIE OF THE PRINCIPLES OF PLANT-BREEDING 59 The third type of variation which is of impor- tance to the plant - breeder is that produced by hybridization or crossing, and here we probably have the most prolific source of variations, and, therefore, the class of variation of the greatest importance and most consequence to the breedej It has come to be an established policy to combine the good qualities of two races into a single race by hybridization and selection. Iiijiuence of environment.— It is a well-known fact that environment has a decided in- fluence on the form and char- acter of the. Fig. 80. Dwarf leafy sport or mutation of com on left, which, when self-pol- linated, reproduced original type. Mother parental types on right. plant. It is by no means cer- tain, however, that these changes are of any value to the plant - breeder. It seems certain that those changes which are the conse- quence of en- vironmcnt purely are not hereditary. It is a well-known fact that if climbing or twining beans or viny cowpeas are transferred from a south- ern to a northern climate or from a lower to a higher altitude, they tend to produce a dwarfed type which will not show the twining or viny habit in such marked degree ; and in order to secure bush types by selection, breeders have sometimes advocated the transferring of types to more northern latitudes or to higher altitudes, where the may be made under conditions that naturally lead to the production of a lower bush type. It is doubtful, however, whether such a transfer would be of material aid. While it is recognized that such variations are produced as an influence of the environment, it is also known that, on the whole, those variations which are produced as an immedi- ate influence of the environment are not hereditary. Individual variations and mutations are of greatest use to the plant-breeder. Without question, if the cowpea or bean were cultivate
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