IDENTIFICATION OF A NEW RESISTANCE GENE TO A CHINESE BLAST FUNGUS ISOLATE IN THE JAPANESE RICE CULTIVAR AICHI-ASAHI

Genetic analysis of the rice cultivar Aichi Asahi and some other Japan ese cultivars for the high resistance ro the blast fungus isolate CHNO S58-3-1 from China was performed. All the Japanese differential cultiv ars were resistant to the isolate except for 'Pi No. 4', which showed moderate resistance. Analysis of the Fz population of a cross of the s usceptible cultivar Reiho and the resistant cultivar Aichi Asahi indic ated that the resistance of 'Aichi Asahi' to the isolate was conferred by one dominant gene. To identify the gene in other Japanese differen tial cultivars, AK lines, which were derived from a cross of 'Aichi As ahi' x 'K59' and assumed to harbor no known genes except for the new o ne, were used for the allelism tests. The new, completely dominant res istance gene was detected in 14 differential cultivars, but not in 'Pi No. 4','Yashira-mochi', and 'K1', and was designated as Pi19(t). Pi19 (t) was allelic or closely linked to Pita(2) on chromosome 12. Pi19(t) was extensively distributed among Japanese traditional local cultivar s.