Resistance to Infection of Rice Tungro Viruses and Vector Resistance in Wild Species of Rice (Oryza spp.).

Abstract

Fifteen accessions of 8 species of wild rice (Oryza spp.), which were found to be resistant to rice tungro bacilliform virus (RTBV) infection, were reexamined to determine whether resistance was attributed to vector resistance. Of the 15 accessions, 3 of O. rufipogon (IRGC Acc. no. 105909, 105908 and 105910) showed low or moderate level of antibiosis to the major vector Nephotettix virescens; they were resistant to infection of tungro viruses, regardless of vector resistance. Three accessions of O. officinalis (IRGC Acc. no. 105100, 105365 and 105376) showed high levels of antibiosis to N. virescens, but they showed low levels of antibiosis to N. nigropictus. These O. officinalis accessions were not infected with RTBV in the mass inoculation test and showed no or low percentage of RTBV infection in the forced inoculation test by N. nigropictus. One O. ridleyi accession (IRGC Acc. no. 100821) showed a moderate level of antibiosis to N. nigropictus and no infection with RTBV in the mass inoculation test. These results suggest that resistance to RTBV infection of these 7 accessions does not depend on vector resistance. These wild rice accessions can be useful in developing rice cultivars with high resistance to tungro. PU - JAPANESE SOC BREEDING PI - BUNKYO-KU TOKYO PA - UNIV TOKYO FACULTY AGRICULTURE, BUNKYO-KU TOKYO 113, JAPAN