Identification and Comparison of Diploid and Tetraploid Hybrids of Oryza sativa × O.meyeriana

Genomic in situ hybridization(GISH) was used to identify the trueness of diploid and tetraploid hybrids of Oryza sativa and O.meyeriana in this research.To explore the effect of polyploidization on diploid hybrid,compared and analyzed the cause of sterility and the application potency of hybrids,the agronomic traits and meiosis of diploid and tetraploid hybrids.GISH detection proved the trueness of hybrids,since O.meyeriana chromosomes gave off red fluorescence signals,while cultivated rice chromosomes had no signals.Many agronomic traits,such as plant height,flag leaf length,spikelets per panicle,spikelet length,and width of tetraploid hybrid increased much more than those of diploid hybrid,showing obvious predominance of polyploid.The meiosis behaviors of diploid and tetraploid hybrids were also different from each other.The meiosis was disorder in diploid hybrid,but normal in tetraploid hybrid.Doubling of chromosomes improved the meiosis obviously,but tetraploid hybrid was still acarpous which may be related to the nucleo-cytoplasmic incompatibility.The hybrids had the potential to be modified in rice breeding.Their characteristic of non-awn will also play an important part in genetic research and awn improvement in rice.