Behavior of rice genotypes to Rhiwctonia sp. under controlled inoculation conditions.

Abstract

In order to know the pathogenicity of blight in rice crops, the pathogenicity of Rhizoclonia sp. was studied and rice cultivars with tolerance to Rhizoctonia sp. were identified. To determine pathogenicity, inoculation modalities were studied, which consisted of inoculating seeds in a mycelial water solution of the fungus, incorporating the fungus with rice into the soil, placing two grains of rice with fungal growth on the inner side of the second sheath 30, 50 and 70 days after sowing. It was compared with an absolute control; the Fedearroz - 50 genotype was used. In the genetic reaction test, 10 rice genotypes were evaluated: 1) INIAP 415, 2) INIAP 11, 3) INIAP 12, 4) INIAP 14, 5) INIAP 15, 6) INIAP 16, 7) Fedearroz-50, 8) I001, 9) GO-3815I and IO) G0-38160; these constituted the treatments. A completely randomized design was used. The incubation period of Rhizoclonia sp. under greenhouse conditions varied according to the type of inoculation, as in seed submerged in a water-micellar solution of the fungus was 28 days after inoculation; at 10 days after sowing it was 15 days; when the inoculum was placed on the inner side of the pod, 30 days after sowing, it was 7 days; and 3 days when inoculated at 50 and 70 days in both cases. The critical period for the cultivars studied when inoculated with Rhizoctonia was between 50 and 70 days after sowing.