Identification of blast-resistant varieties from Landrace, improved and wild species of rice

Abstract

An experiment was conducted to identify rice varieties resistant to blast disease. Samples of 311 genetically diversified varieties/accessions comprised of landrace (263), improved (43) and wild (5) rice varieties/accessions were provided by the National Rice Gene Bank of Thailand. The screening for blast at the seedling stage was done using 29 diversified blast isolates. The blast isolates were collected from seven provinces (Phitsanulok, Ubon Ratchathani, Khon Kean, Chiang Rai, Nong Khai, Chaiyaphum and Udon Thani) of Thailand. The results indicated a total of 35 varieties/accessions (25 landrace, 9 improved and 1 wild) were resistant to all tested blast isolates. The 25 resistant landrace varieties were collections from Northern (10), Northeastern (9) and Southern (6) Thailand. Moreover four of the resistant landrace varieties (GS23107, GS19769, GS20874 and GS23774) were highly resistant with no symptom of the disease. From this study, it can be suggested that the resistant landraces from the Southern, Northern and Northeastern regions could be used as sources of resistant varieties in designing future breeding programs aimed at developing disease-resistant genotypes.