. 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. 58 SOME OF THE PRINCIPLES OF PLANT-BREEDING that ordinarily like bocjets like, but it is also true that Uko fre<iuently crives rise to unlike. There are thus apparently two contlictinj; principles in plant- breeding. On the one hand, the breeder seeks to 1<. 4 % i Fig. 78. Individuality in cotton bolls. Smooth seeds above ami fuzzj- ones below, from four boUs of one hybri
. 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. 58 SOME OF THE PRINCIPLES OF PLANT-BREEDING that ordinarily like bocjets like, but it is also true that Uko fre<iuently crives rise to unlike. There are thus apparently two contlictinj; principles in plant- breeding. On the one hand, the breeder seeks to 1<. 4 % i Fig. 78. Individuality in cotton bolls. Smooth seeds above ami fuzzj- ones below, from four boUs of one hybrid plant. produce variations in order to get new types as the foundations for improvement. On the other hand, when such a variation from or improvement on the normal type is secured, he then reverses the pro- cess and tries to establish heredity and reduce the amount of variation, so that the aphorism, "like begets like," will hold true. In pedigree or grade breeding, and in breeding to produce new varieties, the importance of hereditary strength, prepotency or transmitting power, cannot be overestimated, as it is only by rendering this power very great that any new form can be brought to what is called a fixed type. Vnity of individual.—The unity of the individual is also an important factor in plant-breeding. If, for instance, the breeder is attempting to produce a seedless fruit, it is important that he discover the tendency to seedlessness in the entire individual. It would not be the correct policy for a breeder to select simply a single fruit which might acciden- tally be nearly seedless. He should examine a large number of fruits of different individual plants, and find a plant on which he can discover a general tendency toward seedlessness showing in all of the fruits produced. By selecting seed from such indi- viduals, he may be able to find in time one such individual that would transmit to its progeny this tendency to produce few seeds. While this is certa
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