%A S Gopalakrishnan %A S S Dudeja %I Indian Society for Plant Physiology %V 4 %L icrisat5539 %J Indian Journal of Plant Physiology %N 1 %P 6-9 %D 1999 %X Nineteen Rhizobium and Bradyrhizobium strains isolated from pigeonpea and screened for their ability to grow at high temperature in liquid medium showed that the optimum temperature of growth for 7 strains was 30°C and for 5 strains 37°C. Other strains like PP 1008, PH 8866, PH9038 and PP309 were able to grow under a wide range of temperatures up to 42°C. A thermotolerant variant of strain PP2015-1 was able grow up to 44°C, although the optimum temperature remained the same as that of the parent strain. No correlation could be observed between thermotolerance of a strain and its efficiency with the pigeonpea host grown in the range of 35 to 42°C. %T Temperature tolerance and effectiveness of Rhizobium strains infecting pigeonpea (Cajanus cajan L.) host