Page:Popular Science Monthly Volume 77.djvu/208

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 At the right average of the parents after three generations inbreeding, 61 bushels per acre. At the left crop of first generation cross of the inbred strains, 101 bushels per acre.

them the grower obtains two strains and plants them in alternate rows. At flowering time all of the male flowers or tassels are removed from one of the plants of the varieties before they shed their pollen. All the ears that these plants produce are crossed with the other variety. It is this seed that produces the vigorous plants.

This method might be made the basis for some very valuable work in forestry. It is quite conceivable that many important timber trees might be found where nearly related species or varieties would cross readily. Experiment would show how great an increase in rapidity of growth could be expected., and whether such an increase would pay for the increased expense of hand hybridized seed.