Oryza sativa and O. latifolia belong to the AA and CCDD genomes of Oryza, respectively. In this study, interspecific hybrids of these species were obtained using the embryo rescue technique. Hybrid panicle traits, such as long awns, small grain, exoteric large purple stigma, grain shattering and dispersed panicles, resemble that of the paternal parent, O. latifolia, whereas there is obvious heterosis in such respects as plant height, tillering ability and vegetative vigor. Chromosome pairing and the genomic components of the hybrid were subsequently investigated using genomic in situ hybridization (GISH) and fluorescent in situ hybridization (FISH) analysis. Based on the mitotic metaphase chromosome numbers of the root tips investigated, the hybrid is a triploid with 36 chromosomes. The genomic constitution of the hybrid is ACD. In the meiotic metaphase I of the hybrid pollen mother cell, poor chro- mosome pairing was identified and most of the chromosomes were univalent, which resulted in com- plete male sterility in the hybrid.
YI ChuanDeng TANG ShuZhu ZHOU Yong LIANG GuoHua GONG ZhiYun GU MingHong
将亚洲栽培稻(Oryza sativa,染色体组型为AA)与宽叶野生稻(O. latifolia,染色体组型为CCDD)进行杂交,结合胚拯救手段,获得了这两个种的种间杂交种.杂种F1在株高、分蘖力、生长繁茂性等方面表现明显的杂种优势,穗部性状明显偏向于父本宽叶野生稻的特征,表现为长芒、小粒、大而外露的紫色柱头极易落粒.根尖细胞染色体鉴定证明杂种染色体数为2n=36.进一步利用基因组原位杂交(genomic in situ hybridization,GISH)和荧光原位杂交(fluorescent in situ hybridization,FISH)技术,鉴定了杂种F1的染色体组成及其在减数分裂中的配对行为.结果表明,杂种染色体的组成为ACD,在减数分裂中,绝大部分染色体以单价体形式存在,很少有配对现象发生,因而杂种表现完全雄性不育。
