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Abstract

Rice blast disease (Magnaporthe oryzae) is one of the major biotic factors limiting rice production. An experiment wasconducted in four locations to screen and identify upland rice accessions that are resistant to Magnaporthe oryzae. 25 uplandrice landraces were collected and screened against Magnaporthe oryzae by artificial inoculum under the field condition in fourlocations for two cropping seasons. The experiments were laid in a Randomized Complete Block Design with threereplications across the locations. Data were collected on grain yield, the weight of 1000 seeds, numbers of tiller per plant,panicle weight, grains per panicle, and plant height. Disease scoring was done using the Standard Evaluation System of theInternational Rice Research Institute and analyzed with IRRI STAR software. The screening result revealed that none of the 25prominent upland rice landrace accessions is highly resistant or resistant. Five accessions; Acc. 1, Acc. 2, Acc. 7, Acc. 10, andAcc. 22 were moderately resistant, 11 accessions were moderately susceptible while eight accessions were susceptible. Noneof the accessions screened is highly susceptible to the pathogen. All moderately resistant accessions that gave high grain yieldcould be used as a gene pool for Magnaporthe oryzae resistance breeding for cultivar improvement except accession 22 thatrecorded a low grain yield. The use of the identified moderately resistant accessions with high yield by farmers is encouragedpending the time commercial Magnaporthe oryzae resistant cultivars will be readily available and accessible in rainforest andderived guinea savanna agro-ecological zones of Nigeria. © 2021 Department of Agricultural Sciences, AIOU