The lesion type, neck blast percentage and AUDPC data suggest that Radha 7, Radha 9, Radha 11 and
Masuli are susceptible genotypes. Under field conditions, all the advanced breeding lines possess higher
level of resistance to leaf and neck blast. The genotypes having higher rating of leaf blast scored higher
percentage of neck blast too; suggesting that compatible inoculum from leaf blast could serve for neck
blast infection. A similar finding was reported by Hwang et al (1987). However, there was an exception
that statistically, Radha 7 had the highest neck infection, although it had significantly less leaf blast than
that of Masuli. This indicates that resistance to neck blast may be expressed in some genotypes of rice
independently of that to leaf blast. Gangopadhyay and Padmanabhan (1987) and Chaudhary (1995)
reported the similar results. Hence, evaluation of genotypes for both leaf and neck blast is required in
field condition before recommendation for release.
Greenhouse assays
The rice genotypes differed for lesion type within and between isolates (Table 3). The lesion type varied
from 0.0 to 5.0 in rice seedlings inoculated with different isolates. Isolate K59-1L produced sporulating
lesions on 18 rice genotypes, N 22-1L on 13 and Kanto 51-11R on 11.