Plant-breeding; comments on the experiments of Nilsson and Burbank . d, it is almost sureto be exclusively self-fertilized and its progeny will at onceyield a pure and uniform race. In corn, however, a selected ear will almost always bepartly cross-fertilized, and probably by the pollen of morethan one of its neighbors. If we could eliminate these hybridkernels and sow only the self-poUinated seeds, we might ex-pect to get at once a pure and uniform race, which would needonly careful protection against foreign pollen during the firstyear of its multipUcation. There can be hardly any doubtthat
Plant-breeding; comments on the experiments of Nilsson and Burbank . d, it is almost sureto be exclusively self-fertilized and its progeny will at onceyield a pure and uniform race. In corn, however, a selected ear will almost always bepartly cross-fertilized, and probably by the pollen of morethan one of its neighbors. If we could eliminate these hybridkernels and sow only the self-poUinated seeds, we might ex-pect to get at once a pure and uniform race, which would needonly careful protection against foreign pollen during the firstyear of its multipUcation. There can be hardly any doubtthat this conclusion, drawn from the other cereals, wouldhold good for corn also. At present, however, it is impos-sible to distinguish the cross-fcrtiUzed kernels of an ear fromthe self-polHnated seeds, except in such extreme cases as wehave just alluded to. The only way is to sow all the seeds,and to judge the plants when growing. In some instancesthe hybrids may be recognized and thrown out before tassel-ing, but ordinarily they will have to stand in the field until. 125 126 PLANT-BREEDING the time of husking. Part of their pollen will be carried tothe true representatives of the chosen race, and repeat the mixture of the charac-ters of the paternal and •maternal strains. It is easily seen thatin the ordinary processof selection, the result ofthis open fertiHzing con-dition must be that thechoice is partly initialand partly repeated orcontinuous. The initialchoice is the main one onwhich almost all furthersuccess depends, but therepeated choice gradual-ly eliminates the Ijadeffects of the una^•oidablecross-fertilization of the^^??iiiMt^m ? iTffc ^fiillrt>i fir^t chosen ear. The >.^«/-i^^^.? ??.iJi^ :fla^B?l initial choice corresponds to the Svalof method butthe subsequent repeatedchoice can be comparedwith the German meth-od, as described in myprevious to put it in other words, the pedigree on the femaleside is pure and fully known, but on the male side it i
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