ISHS Acta Horticulturae 367: VI International Symposium on Pear Growing
STUDIES ON CHROMOSOME OF PYRUS IN CHINA |
| Authors: | L. Shenghua, F. Chengquan |
| Keywords: | Pyrus, species, cultivar, chromosome, number, polyploid, China |
| Abstract:
In this paper chromosome numbers of 200 hybrids, 350 cultivars, 11 forms, and 12 species of Pyrus in 22 provinces of China were observed with the wall degradation hypotonic method. The results indicate that the wall degradation hypotonic method of preparing mitotic chromosome samples of Pyrus has the advantages which are easy to sample, easy to operate, and the clear image as compared with a conventional squash method. The observation discovers: Pyrus armeniacaefolia is triploid(2n=3x=51); P.ussuriensis has diploid(2n=2x=34) and triploid(2n=3x=51) cultivars; P.bretschneideri has diploid(2n=2x=34), triploid(2n=3x=51), and tetraploid(2n=4x=68) cultivars; diploid(2n=2x=34) and triploid(2n=3x=51) cultivars of P.pyrifolia exist; diploid(2n=2x=34), triploid(2n=3x=51), and tetraploid(2n=4x=68) cultivars exist in P.sinkiangensis; P.phaeocarpa, P. betulaefolia, P.hopeiensis, P.serrulata, P.pashia, P.xerophilus, and P.calleryana are all diploid(2n=2x=34). The studies show that Pyrus in China produces a change in chromosome number in the evolutional process. It not only has polyploid species but also has polyploid forms and cultivars in a same species. It will enable to enrich the polyploid composition of Pyrus in the world and may be used in the production, the genetics, and the breeding of pear. | |
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