Title: Genetics in relation to agriculture
Identifier: cu31924001155310 (find matches)
Year: 1918 (1910s)
Authors: Babcock, E. B. (Ernest Brown), b. 1877; Clausen, Roy Elwood, 1891-
Subjects: Livestock; Heredity; Variation (Biology); Plant breeding
Publisher: New York, McGraw-Hill; (etc. , etc. )
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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GRAFT-HYBRIDS AND OTHER CHIMERAS 375 first type is termed sectorial and the second periclinal. A third type has been recognized by Winkler in which the vegetative cone is a mosaic of unlike cells. This type he named hyperchimera. Coit has reported the case of a Valencia orange tree which from its consistent instability appears to have been propagated from a mixed bud and hence belongs in this class of chimeras. All of Winkler's Solanum chimeras are periclinal and the degree of resemblance of such a graft-symbiont to the parent whose tissue comprises the inner portion of the shoot seems to depend upon the number of layers of cells from the other parent which envelop it. Thus the form tubigense
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A B Fig. 151.— Winkler's Solanum chimeras. Produced by grafting tomato on nightshade (and vice versa). From left to right, Solanum Gaerinerianum, S. Koelreuterianum, S. proteus, and iS. tubigense. The second resembles the tomato parent most closely; it has a tomato body with nightshade epidermis (a single layer of cells). The fourth is most like the nightshade parent and it has a nightshade body with tomato epidermis. The first has a tomato body covered with 2 layers of nightshade cells and the third, a nightshade body covered with two layers of tomato cells. Such combinations are called periclinal chimeras. (From Journal of Heredity.) (Fig. 151, D) which closely resembles the nightshade has all the inner portion of S. riigrutn, with just an epidermal layer, one cell thick, of S. lycopersicum. But proteus (Fig. 151, C), whose leaves are much more like tomato leaves, has a double layer of tomato cells overlying the nightshade body. Similarly, Kcelreuteriammi (Fig. 151, B) is really a tomato with nightshade epidermis, while GcErtnerianmn has a tomato body covered with two layers of nightshade cells. These graft-hybrids were discovered only after much patient work in the course of which Winkler made 268 grafts which produced more than 3000 shoots. All four were propagated from cuttings and by this method they have been obtained and grown by the New York Botanical Garden. It has not been possible to compare these forms with true sexual hybrids because no one has yet succeeded in crossing the tomato and the Digitized by Microsoft®

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