ISHS Acta Horticulturae 587: International Symposium on Asian Pears, Commemorating the 100th Anniversary of Nijisseiki Pear
GENETICS OF PLOIDY AND HYBRIDIZED COMBINATION TYPES FOR POLYPLOID BREEDING IN PEAR |
| Authors: | Y. Cao, L. Huang, S. Li, Y. Yang |
| Keywords: | Pyrus, hybridization, combination type, genetics, diploid, triploid, tetraploid, aneuploid |
| DOI: | 10.17660/ActaHortic.2002.587.24 |
| Abstract:
Two tetraploid (2n=4x=68) Pyrus cultivars ‘Dayali’ and ‘Sha 01’; three triploid (2n=3x=51) pear cultivars ‘Anli’, ‘Dashuihe’ and ‘Baipiyang’; and seven diploid (2n=2x=34) pear cultivars ‘Qinsu’, ‘Jinhua 4’, ‘Dananguo’, ‘Kuerlexiang’, ‘Qiubai’, ‘Pingguoli’ and ‘Bartlett’ were chosen as seed or pollen parents to study the genetics of pear ploidy. Eight hybridized combination types were designed and 25 crossings were performed. The chromosome numbers of 725 hybrid seedlings were observed. It was found that 516 seedlings were diploid, and the ratio of diploid was 71.2%; 91 seedlings were triploid, and the ratio of triploid was 12.6%; 74 seedlings were tetraploid, and the ratio of tetraploid was 10.2%; 44 seedlings were aneuploid, and the ratio of aneuploid was 6.0%. We analyzed the efficiency of every hybridized combination type for polyploid pear breeding and found: 1) 4x×4x is the best combination type for tetraploid breeding; 2) 4x×3x, 3x×4x are efficient combination types for polyploid breeding, especially for triploid breeding; 3) 4x×2x is the ideal combination type for triploid breeding; 4) 2x×4x, 3x×3x, 2x×3x, 3x×2x are not good combination types for polyploid breeding. | |
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