Gene resources of Oryza rufipogon Griff. play a crucial role in rice breeding, and hence to study their conservation is of utter importance. The authors describe a method for preparation of DNA from mini_amount of the silica_gel_dried leaves of Oryza rufipogon . The high molecular weight DNAs of 1?168 individuals representing 44 populations have been obtained with high yields, which could be used for RAPD PCR and construction of total DNA bank of this species. The template DNA from silica_gel_dried leaves stored for one year at room temperature gave the same RAPD results as that from the newly prepared silica_gel_dried leaves. The optional template DNA concentrations for amplification ranged from 3.1 ng to 50 ng. In addition, the quality and quantity of the template DNAs that affect RAPD results are also discussed.
The genus Oryza consists of two cultivated species (O. sativa L. and O. glaberrima Steud.) and approximately 20 wild relative species widely distributed in the pan-tropics. These species have been classified into four complexes following the Vaughan's taxonomic system([1]). The O. officinalis complex is the largest complex in the genus, which includes ten species, having BE, CC, on, and EE genomes in the diploids as well as BBCC and CCDD genomes in the tetraploids. The relationships among the BE, CC, and EE genomes still remain unclear, although previous studies have indicated certain affinities of these genomes([2-4]). Genomic in situ hybridization (GISH) is a powerful technique to detect the relationships among the related genomes at chromosome and DNA levels. The objective of the present study was to investigate the relationships among the BE, CC and EE genomes in the genus Oryza by the two-probe GISH.
