Enzyme Identification of Austrian X Japanese Red Pine Hybrids in Seed From Mixed Pollen Controlled Crosses
Mixed pollen samples with 10:90, 50:50, and 90:10 percent of Pinus densiflora and P . nigra pollen respectively were used to control pollinate P . nigra seed trees. The test was undertaken to determine if hybrids were produced in proportion to P . densiflora pollens in the mixes. Offspring embryos were electrophoresed and hybrid offspring were identified using alcohol dehydrogenase alleles that differed between the two species. In all three pollen-mix treatments, hybrid production was significantly reduced over that expected from the ratio of P . densiflora species pollen in the mix. With low and moderate concentrations of P . densiflora low frequencies of hybrids are produced. The pollen mix had to contain high concentrations of P . densiflora pollen before significantly large proportions of hybrids were produced. The data supports the hypothesis that native embryos are highly favored over hybrid embryos as judged by the proportion of hybrids in the resulting seed, The results are discussed briefly with reference to the suggestion that hybrids can be mass produced by natural fertilization of mixed plantings of P . nigra and P . densiflora trees.
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Author(s): James J. Tobolski, M. Thompson Conkle
Publication: Tree Improvement and Genetics - Central States Forest Tree Improvement Conference - 1976