Evaluation of forty‑five rice ( <i>Oryza species</i> ) accessions for resistance to rice blast ( <i>Magnaporthe oryzae</i> ) disease under natural conditions

Abstract

Abstract The experiments were conducted to investigate the resistance levels among forty‑five lowland rice accessions at the Teaching and Research Farm, Federal College of Agriculture, Ishiagu (Latitude 5°56″N and Longitude 7°41″E) Ebonyi State, Nigeria. Forty‑five rice accessions were screened for their resistance to the blast disease in row planting during the 2017 and 2019 cropping seasons using Randomised Complete Block Design (RCBD) and were replicated thrice. The data on disease intensity and agronomic performance were subjected to Analysis of Variance and the significant means were separated with the Tukey HSD test at p &lt; 0.05. Assessment of blast disease showed that the incidence, severity, and resistance levels varied significantly among rice tested. Accession NG / SA / JAN / 023 had the highest disease incidence (59.06 %) while accessions NG / SA / DEC / 07 / 0300, TOG 5453, TOG 6804, FARO‑22 and FARO‑57 had no blast symptoms for the two cropping seasons. The disease severity ranged from 0.00 to 3.43 for the two cropping seasons. Five accessions (NG / SA / DEC / 07 / 0300, TOG‑5453, TOG‑6804, FARO‑22, and FARO‑57) were highly resistant, 10 were resistant, 14 moderately resistant, and 16 were moderately susceptible to the disease. In the 2017 cropping season, the result of the grain yield showed that accession Local Foreign and FARO 26 had the value of 46.77 g apiece while NG / SA / DEC / 07 / 0278 had the least (11.00 g). However, in the 2019 cropping season, the results of the grain yield showed that accession Local Foreign produced the highest yield (56.00 g), FARO 26 had 40.31 g grain yield while NG / SA / DEC / 07 / 0285 (22.0 g) had the lowest grain yield. The study concluded that using the blast‑resistant cultivars is the best option in managing blast disease, and the five highly resistant accessions could be planted out in other agroecological zones for further studies on managing rice blast disease in the field.