Abstract

Rice is one of the main food crops in Burkina Faso, but its production is seriously threatened by rice bacterial leaf blight, a disease responsible for yield losses of over 50% in 1998 and 2004. The aim of this study was to evaluate the phenotypic response of new rice lines to this disease caused by Xanthomonas oryzae pv. oryzae. A trial was carried out under semi-controlled conditions with 12 rice lines, five of which were derived from crosses between various parental varieties, and two elite local varieties included as controls. The BAI3 strain of Xanthomonas oryzae pv. oryzae, identified as the most virulent in Burkina Faso, was used for inoculation. Analysis of variance revealed significant differences in susceptibility between the lines, their parents and the controls. Lines AR19L025-F4-117 and AR19L018-F4-22, as well as their respective parents IRBB60 and CT21376-F3-9-1, showed strong resistance, with leaf lesions of less than 10 cm. Conversely, the FKR64 and ARICA3 lines suffered a total loss of yield, with complete wilting 45 days after inoculation. Correlation analysis revealed a significant negative relationship between disease severity and several yield components. For example, the average sterility rate was 28.47% in inoculated plants, compared with 18.57% in unifected plants. The average number of panicles per plant fell from seven (07) to five (05) after inoculation. The AR19L018-F4-22 and AR19L025-F4-117 lines, combining productivity and resistance, showed promise, with the confirmed presence of the Xa4 and xa5 resistance genes. Further research is needed to assess their ecological adaptation in endemic areas.