STUDY ON INCIDENCE AND SEVERITY OF BLAST, BACTERIAL LEAF BLIGHT AND SHEATH BLIGHT IN SELECTED INDIGENOUS RICE VARIETIES

Abstract

The study was conducted to assess the performance of six indigenous rice varieties (Binni Pakri, Uknimodhu, Sanla, Bolder, Zetha Katari, and Jira Katari) against three major diseases (blast, bacterial leaf blight and sheath blight) during the Aman season of 2023 at the research farm of Hajee Mohammad Danesh Science and Technology University in Bangladesh. The study focused on disease incidence and severity at six different growth stages, as well as the impact of these diseases on yield and related characteristics. During the experiment, Sanla exhibited the highest incidence and severity of leaf blast at 25.68% and 10.32% at 40 DAT, respectively, while Binni Pakri demonstrated the lowest values at 0.32% and 0.05% at 80 DAT. For neck blast, Sanla again recorded the maximum incidence and severity at 29.54% and 13.93% in 90 DAT, with Binni Pakri showing the minimum values at 0.00% in 80 DAT respectively. Regarding bacterial leaf blight (BLB), Binni Pakri had the highest incidence (5.57%) and severity (1.90%) at 80 DAT, while Uknimodhu had the minimum incidence at 0.47% in 40 DAT, and Bolder had the minimum severity at 0.08% in 40 DAT. In the case of sheath blight, Uknimodhu had the maximum incidence and severity at 15.20% and 3.45% in 80 DAT, respectively, while Sanla exhibited the minimum incidence at 0.77% in 40 DAT, and Zetha Katari showed the minimum severity with 0.14% at 50 DAT. The organisms responsible for the three diseases, namely Pyricularia oryzae, Xanthomonas oryzae pv. oryzae and Rhizoctonia solani, were successfully isolated from the leaves that were infected. These organisms were then identified through a detailed examination of their cultural characteristics and the morphology of their conidia. Among the factors influencing yield, Binni Pakri exhibited the greatest panicle length and the highest number of grains per panicle. In terms of overall yield, Binni Pakri stood out with the highest production 3.67 tons per hectare. The superior yield of Binni Pakri can be attributed to its minimum incidence and severity of blast, as it was recorded with the lowest values in this regard.