THE PHYSICAL LOCATION OF 14 RFLP MARKERS IN RICE (ORYZA-SATIVA L)

A biotin-labeled in situ hybridization technique was used in order to physically map RFLP markers to the chromosomes of rice (Oryza sativa L .). Fourteen RFLP markers, associated with the ends of the linkage gro ups on rice chromosomes 7, 8, 11, 12, were physically mapped onto spec ific regions of the chromosomes. The average detection rate of in situ hybridization was 5.91%. The markers were located on seven different chromosome arms. Ten of the fourteen markers were distributed near the chromosome ends. This demonstrated that the RFLP linkage groups invol ved covered a wide physical distance and that the centromeric region w as bisected by all but one linkage group. Two markers covered a short genetic distance but were physically distant, while two covering a lon ger genetic distance were physically closer together. This indicates t hat considerable variation can, and does, exist between genetic and ph ysical maps.