GROWTH INHIBITING AND BLEACHING EFFECTS OF STREPTOMYCIN ON RICE (ORYZA SATIVA L.) GENOTYPES

Thirty six rice genotypes of three different maturity groups were treated with 500 ppm of streptomycin (SM) solution for 48 hrs to study the growth inhibiting and bleaching effects on them. Growth inhibiting and bleaching effects were expressed in terms of seedling growth inhibition and bleaching index, respectively. Growth inhibiting effect of streptomycin was the highest on mid-early genotypes followed by mid-late genotypes and the lowest on late maturing genotypes of rice. Bleaching effect was low on mid-early genotypes and higher on those of mid-late and late genotypes. Correlation study and 2 x 2 contingency classification method revealed that most of the rice genotypes having high seedling growth inhibition or high degree of bleaching were found to be high yielder. Results of the present study indicated that high SM-sensitivity of genotypes in terms of seedling growth inhibition index or bleaching index could be used as an indicator of high yield potential in rice.