Cytomorphological Characterization of the Backcross Progeny of Synthetic Amphiploid Rice (AABB) and Tetraploid Oryza sativa (AAAA)

摘要

DCW008, a synthetic allopolyploid rice (2n = 4X = 48, AABB), was obtained from chromosome doubling of interspecific hybrids between Oryza sativa (2n = 24, AA) and O. punctata (2n = 24, BB). The F 1 and backcross (BC 1 ) hybrids were produced by crossing DCW008 as a female parent with a high seed set tetraploid rice Sg99012 - 4X (2n = 4X = 48, AAAA). BC 1 F 1 and BC 1 F 2 overcame many of the wild-type traits of DCW008; they had yellow-hulled grains, seed set ranged from 0% to 71.31% and the grain morphology was similar to that of cultivated rice. Variable numbers of chromosomes were observed in pollen mother cells (PMCs) from the BC 1 plant. Genomic in situ hybridization (GISH) revealed that the majority of somatic cells and PMCs contained six chromosomes of O. punctata with fragment recombination observed in two of them. The backcross selection method employed in this study to generate allopolyploid progeny provides a reliable way of transferring useful genes from wild species into cultivated rice.