Rhizoctonia affects rice in Venezuela

In the last years rice (Oriza sativa L.) production in Venezuela has been negatively affected by Rhizoctonia solani causing sheath blight of rice (ShB). In order to investigate the inheritance of resistance to the fungus, two experimental populations were obtained from parents of rice resistant and sensitive. At the beginning of the panicle emergence, four leafs with fungus mycelium were applied within knot of sheath, then being placed in humidity chamber for a week. According to the zone affected by the disease, plants were grouped using the assessment scale. The phenotypic reaction showed both progenies with transgressive inheritance, explaining why the populations did not conform to the laws of Mendelian inheritance; also a ratio of 1 resistant was observed: 1 sensitive. Therefore, R. solani resistance was influenced by several genres, considering that resistance was quantitative.