Description

Interspecific crosses provide a bridge by which the gene pool of rice can be increased. Attempts have been made to visualize the genomic constitution of wide-cross derivatives. Genomic in situ hybridization Oryza australiensis chromosomes and introgressed segment from O. australiensis into the Oryza sativa background have been detected. The genomic relationship between Oryza sativa (2n=24 AA) and Oryza australinesis (2n = 24 EE) these two species was assessed by using three strategies: genomic in situ hybridization (GISH), meiotic chromosome pairing, pollen and spikelet sterility. The chromosome pairing was examined in pollen mother cells of O. brachyantha, O. sativa and the hybrid between O. sativa and O. brachyantha. The hybrid was highly sterile with no pollen stain ability. Both parents showed regular meiosis with normal chromosome pairing. The F1 hybrid exhibited limited chromosome pairing. On an average, 0-2 bivalents and 20-24 univalents were recorded at metaphase-1 and 0- 1 univalent at diakinesis. The most frequent configuration was two bivalents and twenty univalent.