Morphological and biochemical resistance traits of tomato cultivars against thrips and bud necrosis virus disease

Abstract

Thrips are emerging pest and vector of Groundnut bud necrosis virus (GBNV) disease in tomato (Solanum lycopersicum Mill.) in India. The objective of this study was to identify and categorize resistant sources of tomato cultivars (genotypes/ varieties) against thrips and associated GBNV disease. Among the 20 cultivars screened, four cultivars found moderately resistant, five cultivars found susceptible, and remaining eleven cultivars found highly susceptible to thrips and GBNV disease. The trichome density and leaf thickness showed highly significant negative correlation with thrips (r=-0.831 and r=-0.747) and per cent disease incidence (r=-0.857 and r=-0.748). Similarly, phenol content of tomato cultivars exhibited highly significant negative correlation with thrips (r=-0.874) and GBNV disease (r = − 0.907). Total sugars content of tomato cultivars found a highly significant positive correlation with thrips (r = 0.875) and GBNV disease (r = 0.911).Two principal components (PCs) were extracted which explained a cumulative variation of 86.51 % in thrips and GBNV disease incidence. PC1 explaining 73.97 % of the variation while PC2 explained 12.5 % of the variation. PC1 had the loadings for trichome density (0.42), leaf thickness (0.37), phenol (0.42), and total sugars (0.39). Tannin (0.92) was loaded in PC2. Morphological traits (trichome density and leaf thickness) and biochemical traits (phenol and tannin content) of tomato cultivars were linked to resistance of tomato cultivars against thrips and GBNV disease and; therefore, could be used as indicator traits in resistance breeding programs to select resistant cultivars.