. Cyclopedia of farm crops. Farm produce; Agriculture. SOME OF THE PRINCIPLES OF PLANT-BREEDING 63. in other characteristics, namely, quality, disease- resistance, drought-resistance and the lilie, and that we see that all of the good qualities of the variety are retained. To do this properly necessi- tates the use of a score-card, on which each char- acter of the plant which is im- portant is given its relative weight or grade. By the use of such a score-card the breeder can judge each character separately, and by the adding up of the scor- ing get the rank of different plants in a comparativ
. Cyclopedia of farm crops. Farm produce; Agriculture. SOME OF THE PRINCIPLES OF PLANT-BREEDING 63. in other characteristics, namely, quality, disease- resistance, drought-resistance and the lilie, and that we see that all of the good qualities of the variety are retained. To do this properly necessi- tates the use of a score-card, on which each char- acter of the plant which is im- portant is given its relative weight or grade. By the use of such a score-card the breeder can judge each character separately, and by the adding up of the scor- ing get the rank of different plants in a comparative way (Fig. 83). Test of transmitting power. A factor of primary impor- tance in all breeding work is the testing of what is termed the transmitting or centgener power. It is for us to know that a certain plant, which, for , gives a heavy yield, has the faculty of transmitting this tendency of producing heavy yield to its progeny (Fig. 84). It is frequently found that two select plants that are equally good so far as their yield is con- cerned will give progeny which, as a whole, differ greatly in this respect. In the progeny of one almost every plant may have in- herited the desired quality, while in the progeny of the other only a few of the plants may show in any noticeable degree the inheri- tance of the quality. To determine the prepotency or transmitting power, it is necessary to grade carefully the progeny of each individual; and this is the primary reason for planting the progeny of different individuals in separate rows or separate plats, so that they may be examined easily. (Fig. 85.) It would seem to be an easy matter, when we plant the progeny of different plants in rows or small plats by themselves, to get the comparative yield, for example, of 100 plants, and from this to figure up the average percentage of the transmitting or centgener power. This matter, hovvfever, is very difficult in many cases. In corn, for example, cer- tain individuals ma
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