Reaction of some rice (Oryza sativa L.) varieties to brown spot disease caused by Bipolaris oryzae (Breda de Haan) Shoemaker

Abstract

In Africa, rice is produced and is a source of food energy in most developing countries. But its cultivation faces to brown spot disease, caused by Bipolaris oryzae (Breda de Haan) Shoemaker, which is a serious seed-borne and seed transmitted disease of rice worldwide.The aim of this study was to screen rice varieties for resistance to brown spot disease in field conditions inYaoundé. A completely randomized Fisher block design with three repetitions was used during 2 growing seasons (2015 and 2016). Growth, yields and disease (incidence and severity) parameters were evaluated on four rice varieties (Nerica 3 and 8, White rice and Kamkou). Results show that height of the Nerica 8 variety (86.03cm) and the number of tillers of Kamkou variety (21.66) were significantly highest compared to others varieties (P<0.05) at 59 Days After Sowing (DAS). There was no significant difference on disease incidence for the different rice varieties at the end of rice plant cycle. However disease severity was lower on Nerica 3(2.71%) and Nerica8 (2.05%) varieties and higher on White variety (4.57%). Hence, Nerica 3 and 8 varieties were more tolerant to brown spot disease than others varieties. Overall, Nerica 3 (3.68 t ha-1) and Kamkou (3.51 t ha-1) varieties resulted in higher yields than white rice 28.93 t ha-1.

Field efficacy of aqueous extracts of Artemisia annua, Commelina benghalensis and Euphorbia hirta on rice growth, yield and brown spot disease incidence

“…For decades, the yields have remained low (1-6 t/ha) according to Ministry of Agriculture and Rural Development (2009) and this has been attributed to neglect of the sector by the government, cultural techniques, and pests and diseases (Djomo et al, 2017). In Cameroon, the most severe rice disease is brown spot caused by Bipolaris oryzae which is responsible for yield reductions in the range 15-52% (Kuate et al, 2021). Disease management through the use of chemical has been reported to be effective for most cereal crops (Kongcharoen et al, 2020).…”