Evaluation of Screening Procedures to Identify Peanut Resistance to Peanut Bud Necrosis Virus (PBNV)

Abstract

Abstract Six peanut genotypes (ICGV 86388, IC 34, IC 10, JL 24, Khon Kaen 60-1, and Khon Kaen 4) were evaluated for reaction to peanut bud necrosis virus (PBNV) in the field and in the greenhouse in Thailand in 2000 and 2001. The objectives of this study were to (a) investigate if disease score or the area under the disease progress curve (ADPC) would be effective in identifying peanut genotypes resistant to PBNV, (b) determine the appropriate time for assessing PBNV resistance under field conditions by means of disease incidence, and (c) identify peanut genotypes having stable resistance to PBNV by considering their responses to mechanical inoculation and field infection. Results from natural infection by PBNV indicated that differences among the genotypes could be observed by 40 d, but not 30 d after sowing (DAS). Genotypes ICGV 86388, IC 34, and IC 10 had lower field disease incidence than JL 24, Khon Kaen 60-1, and Khon Kaen 4. The proportion of treatment mean square for disease incidence was highest at 50 or 60 DAS depending on the trial, indicating that assessment of disease incidence at these dates could best differentiate the reaction of these genotypes to PBNV. ADPC was an alternative to disease incidence for comparing genotypes affected by PBND in the field, as resistant and susceptible genotypes were readily identified. Mostly, a scoring based on disease severity did not facilitate identifying PBNV resistance in the genotypes used in this study. Greenhouse tests yielded similar results to field disease incidences, indicating the usefulness of greenhouse tests in identifying PBNV resistance. Genotypes ICGV 86388, IC 34, and IC 10 were identified as potential resistant sources for breeding for resistance to PBNV.