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NATURAL AND ARTIFICIAL HYBRIDS OF HELIANTHUS MAXIMILIANI X H. GROSSESERRATUS
Author(s) -
Long Robert W.
Publication year - 1959
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1959.tb07071.x
Subject(s) - hybrid , introgression , biology , backcrossing , herbarium , pollen , botany , helianthus , interspecific hybridization , sunflower , horticulture , genetics , gene
L ong , R obert W. (Ohio Wesleyan U., Delaware.) Natural and artificial hybrids of Helianthus Maximiliani × H. grosseserratus. Amer. Jour. Bot. 46(10): 687–692. Illus. 1959.—An investigation of the occurrence of natural hybridization in two perennial sunflowers, Helianthus Maximiliani and H. grosseserratus , was begun in 1950. Subsequently, artificial F 1 , F 2 , and first and second backcross generations were produced. Fertility and vigor were high in all these plants, but F 1 plants appeared to excel the others in these characteristics. Observations in the experimental garden were supplemented by examination of chromosomes in pollen mother cells, comparisons of herbarium collections, and study of wild populations. Evidence pointed to close genetic relationship of the species and to the occurrence of natural hybridization in areas of distributional overlap. In 1957 and 1958, field work in these areas resulted in the scoring of 18 natural populations, 3 of which consisted of both parental species plus putative F 1 hybrids. Two explanations are offered to account for the seeming absence of introgression. The results support the conclusion that natural hybridization leads to the establishment of F 1 hybrids and that introgression does not occur to any significant extent. Although both species display a high degree of interfertility, they are distinct morphologically. For this reason, it is advisable to maintain them as separate species.