Abstract
Studies were undertaken to locate the gene Bph 1 on the linkage map of rice. The trisomic lines obtained from Kyushu University were crossed with 'Kanto PL1' or 'Kanto PL4', which were the parental lines of japonica type rice resistant to the brown planthopper, and had Bph 1 derived from 'Mudgo'. Segregation ratios observed in the F2 generation of four crosses with trisomic A, C, G and H proved to be of the disomic type. But segregation ratio in the cross with trisomic E carrying the extra chomosome of 11th did not fit a disomic ratio. The 11th chromosome corresponds to the linkage group II. Among marker genes belonging to the linkage group II, lg and d-11 are independent of Bph 1, and lg and Pl-1 are also independent of bph2(allelic to, or closely linked with Bph 1). However, it was found that bph2 Iinked with d-2 of the linkage group II at the recombination value of 39.4%
