Page:Popular Science Monthly Volume 77.djvu/354

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348
THE POPULAR SCIENCE MONTHLY

Fig. 4. Showing Absolute Segregation in Second Hybrid Generation. These red and white ears grew from a single self-pollinated ear of the first hybrid generation of a cross between red and white maize.

A. D. Shamel, of the United States Department of Agriculture, crossed these two types. A new type called the Halladay has been produced with the higher number of leaves of the Cuban parent and the stocky habit of growth and large leaves of the Havana parent. The first interpretation of this result was that an entirely new variation had appeared, for the Cuban type usually has but twenty-two or twenty-three leaves. The writer has been able to show, however, that the actual strain of the Cuban used as the parent of the cross has on the average twenty-six leaves, and data have now been collected that show that the new variety is a simple recombination of the characters possessed by the two parents giving an out-door type averaging thirty per cent, greater yield than the old Havana strain. In a similar way Biffen has produced a rust resistant high-yielding wheat by crossing two varieties each of which possessed but one of these desirable qualities. Orton has combined the edible quality of the watermelon with the wilt resistance of the citron, and Webber has increased the ability of the orange to resist cold by crossing with the hardy trifoliate orange.

Recent accurately controlled investigations in hybridization have shown that many apparently complex results yield to simple explanations

Fig. 5. Red Maize Ear with Pericarp removed, showing segregation of yellow and white endosperm beneath it.