Combined results from race analysis undertaken at several different labs indicate that five new variants in the Ug99 lineage were detected from samples collected in East Africa during 2013 or 2014. Probably most significant were the two new SrTmp variants (Races TTKTK and TTKTT) previously reported (see “16 April 2015: BGRI report two new Ug99 variants with virulence to SrTmp detected in Kenya” and Patpour et al. 2015). Further analysis has revealed the presence of three additional new Ug99 lineage races. Details of these additional new races are:

• Race TTHST: Similar to race TTKST (Ug99 + Sr24 vir) but avirulent on Detected in Kenya in 2013 (1 isolate). Source lab: USDA-ARS Cereals Disease Lab, USA (Newcomb et al in prep)
• Race TTHSK: Similar to race TTKSK (Ug99) but avirulent on Detected in Kenya in 2014 (2 isolates). Source lab: AAFC Morden Research Centre, Canada (Fetch et al 2016)
• Race PTKTK: Similar to race PTKSK (Ug99 but avir on Sr21) but virulent on SrTmp. Detected in Kenya in 2014 (5 isolates). Source lab: AAFC Morden Research Centre, Canada (Fetch et al 2016)

These latest results bring the total of known variants within the Ug99 lineage to 13, with yet another SrTmp variant being detected in Kenya. All five of the new variants were detected in Kenya, but as previously reported race TTKTK was also detected in Uganda, Rwanda, Eritrea and Egypt in 2014. The results indicate that the Ug99 race group continues to evolve at a rapid rate.