Screening of upland-rice landraces for resistance to rice blast disease (Magnaporthe oryzae)

Abstract

Rice blast disease (Magnaporthe oryzae) is one of the major biotic factors limiting rice production. An experiment was
conducted in four locations to screen and identify upland rice accessions that are resistant to Magnaporthe oryzae. 25 upland
rice landraces were collected and screened against Magnaporthe oryzae by artificial inoculum under the field condition in four
locations for two cropping seasons. The experiments were laid in a Randomized Complete Block Design with three
replications 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 the
International Rice Research Institute and analyzed with IRRI STAR software. The screening result revealed that none of the 25
prominent upland rice landrace accessions is highly resistant or resistant. Five accessions; Acc. 1, Acc. 2, Acc. 7, Acc. 10, and
Acc. 22 were moderately resistant, 11 accessions were moderately susceptible while eight accessions were susceptible. None
of the accessions screened is highly susceptible to the pathogen. All moderately resistant accessions that gave high grain yield
could be used as a gene pool for Magnaporthe oryzae resistance breeding for cultivar improvement except accession 22 that
recorded a low grain yield. The use of the identified moderately resistant accessions with high yield by farmers is encouraged
pending the time commercial Magnaporthe oryzae resistant cultivars will be readily available and accessible in rainforest and
derived guinea savanna agro-ecological zones of Nigeria. © 2021 Department of Agricultural Sciences, AIOU