Molecular assessment of selected rice genotypes to study their reaction to brown planthopper and underlying resistance mechanisms

Abstract

Six promising rice genotypes (IET 23993, GSR 234, RNR 23079, Bobhu Kongbu, HHZ 25-DT-1-DT-1 with HHZ 25 SAL DT 1-DT-1) quality yield attributes were identified as moderately resistant to brown planthopper after preliminary studies based on Standard Seed box screening test (SSST). These six genotypes were further investigated to determine the kind of host plant resistance mechanism(s) operating in them along with two resistant checks viz., PTB33 and BM71 and one susceptible check i.e., TN1. IET 23993 was found to possess all three types of resistance mechanisms viz., antixenosis, antibiosis and tolerance while the genotype GSR 234 exhibited only two types of mechanisms i.e., antixenosis and tolerance. The other four genotypes viz., RNR 23079, HHZ 25-DT-1-DT-1, HHZ 25 SAL DT 1-DT-1, and Bobhu Kongbu exhibited moderate level of either antibiosis or antixenosis mechanisms. Molecular analysis using specific SSR markers could able to assess the reason for exhibition of all three types of resistance mechanisms was due to likely presence of five Bph resistance genes in IET 23993.