Profiling of monosporidial populations of Tilletia barclayana causing kernel smut of rice

Abstract

Kernel smut of rice caused by Tilletia barclayana has become a notable constraint in hybrid seed production of rice in many rice producing countries worldwide. The disease is reported to cause 20–50 per cent yield and quality losses in parental lines of hybrid rice. No commercial cultivar has been reported to possess complete resistance against the pathogen. Teliospore germination studies in laboratory and pathogenic variability studies in field indicated that the virulence of different isolates of T. barclayana are correlated with the sporidial production index of various isolates. On the basis of pathogenicity data of 14 different isolates of T. barclayana, the isolates were grouped into 2 major clusters at 40% level of similarity index. Tb-24 was the most virulent isolate which emerged as a separate lineage from all the other isolates. A total of 10 URPs were used to study the variability among T. barclyana isolates at genetic level. High range of variability (95.6% polymorphism) was obtained with all the primers used for amplification of fourteen monosporidial isolates. Isolate Tb-24 had a distinctive banding pattern with unique bands of approximately 3 kb and 500 bp indicating its genetic difference from all other isolates of T. barclayana.