Heritability and phenotypic correlation of resistance to Peanut bud necrosis virus (PBNV) and agronomic traits in peanut

Abstract

Peanut bud necrosis virus (PBNV) is a potential threat to peanut production in Thailand. Therefore, the improvement of peanut lines, which are resistant to PBNV and maintain acceptable agronomic traits, is important. The objective of this study was to estimate broad sense heritability and phenotypic correlation in 16 crosses of the F2 populations derived from cross of four resistant parents with four large-seeded peanut cultivars. A randomized complete block design with four replications was used. Peanut bud necrosis disease (PBND) incidence, PBND score and agronomic data were recorded. Estimates of heritability for PBND score on F2 individual plants were low at 60 days after sowing (DAS) and seemed to be improved at 70 DAS. Estimates of heritability for agronomic traits varied over crosses and traits and were generally low. However, high heritability estimates were observed for 100 seed weight in cross KKU 72-1 × IC 10 and for shelling percentage in crosses KKU 72-1 × IC 34 and Luhua 11 × ICGV 86388. High positive correlation coefficients were found among PBND score, PBND incidence and area under disease progress curve (AUDPC) but all PBNV resistance parameters had low correlation with all agronomic traits. High positive correlation coefficients were found among pod weight per plant, pod number per plant and seed weight per plant. Because of low heritability estimates for PBNV resistance and agronomic traits, selection among individual plants in the F2 generation will be ineffective. Selection should be carried out in advanced generations or on the progeny performance as family mean basis