Field evaluation of late leaf spot and leaf rust resistance and the associated yield losses in Indonesian groundnut genotypes

Abstract

Background and Objective: Groundnut is the second most important pulse crop in Indonesia and the most important one in the semi-arid region of East Nusa Tenggara province. Productivity of this crop in the farmer level is low due to many factors. Late leaf spot and leaf rust are the most significant diseases of groundnut that can cause considerable yield losses. Information on disease resistance and associated yield losses in Indonesian groundnut genotypes is lacking. The present study aimed at elucidating late leaf spot and leaf rust resistance levels of Indonesian groundnut genotypes and assessing yield losses caused by the diseases. Materials and Methods: Five groundnut genotypes were evaluated in three environmental sets, i.e., protected, late leaf spot and leaf rust plots. Observed variables included incubation period, disease severity, AUDPC, defoliation (%), number of pustules and pod yields. All data, except for disease severity score were subjected to variance analysis, followed by DMRT post hoc test and correlation analysis. The disease severity score was analyzed using Kruskal Wallis procedure followed by Mann Whitney U-test. Results: Research results showed significant variations in observed variables of leaf spot and leaf rust diseases and the associated yield losses in the tested groundnut genotypes. Local Rote was ‘moderately resistant' while the Indonesian released varieties were ‘susceptible' and ‘highly susceptible' to late leaf spot. The tested genotypes showed ‘susceptible’ and ‘highly susceptible’ reactions to leaf rust. Pod yield loss caused by late leaf spot and leaf rust diseases ranged from, respectively, 15-57 and 23-57%. Conclusion: Only Local Rote was moderately resistant to late leaf spot and the others were susceptible and none of the genotypes was resistant/moderately resistant to leaf rust. Yield lost caused by late leaf spot was low to high levels while that of leaf rust was moderate to high levels.