Abstract

Rice blast caused by Magnaporthe grisea is an economically important disease which distributed in most rice growing areas of the world. Yield losses up to 100% are attributed to the blast disease in different rice growing regions of Uganda. In order to combat this disease screening of forty-six introduced Korean rice accessions and two checks IR-64 (resistant) and NERICA-1 (susceptible) were done in a 6 by 8 alpha lattice design in two replications under natural infestation in field conditions, and three replications in the screen house at National Crops Resources Research Institute (NaCRRI) of Uganda in 2015, A and B seasons. Final leaf blast severity, lesion size, area under disease progress curve (AUDPC) values, panicle blast and grain yield were highly significant among genotypes. Genotypes SRHB-133, SRHB-93 and SRHB-78 were resistant to rice blast in both field and screenhouse conditions and showed a lower lesion size. Therefore, these genotypes that consistently showed resistance to rice blast disease can be used as a source of resistance gene for rice blast. This leads to conclude that screening in both the field across seasons and confirming their resistance in the screen house helps the breeder to identify the genotypes that are truly resistant for further utilization as resistant sources.

Key words: Rice blast, screening, Magnaporthe grisea, Uganda.