Prospects of resistance of some Sudanese tomato accessions to tomato fruit borer (Tuta absoluta )(Meyrick,1917) (Lepidoptera: Gelechiidae) and its mechanism

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Abstract A field experiment was conducted at Kassala and Gash Research Station farm, Kassala, Sudan for three consecutive seasons to evaluate resistance of 16 tomato entries to tomato fruit borer Tuta absoluta (Meyrick,1917) (Lepidoptera: Gelechiidae). The entries consisted of 12 Sudanese local tomato accessions compared to 4 hybrids widely cultivated in Sudan. The experiment was arranged in a randomized complete block design with three replicates following the cultural practices recommended by the Agricultural Research Corporation of Sudan. Parameters of interaction of the pest with plant included number of active mines/plant, percentage of infested plants/ plot, percentage of infested fruits (%) were assessed and used as indicators for resistance to tomato fruit borer while plant characters including days to 50 % flowering, fruit diameter (cm), total soluble solids (TSS), density of trichomes/cm2 (DT), chemical constituents and yield (ton/ ha) were assessed and their role in resistance was determined and discussed using Pearson correlation. The interaction of the pest with tomato entries revealed high significant differences between entries (pr > f < 0001) in the percentage of infested plants/plot, number of active mines/plot, percentage of infested fruits/plot for the three consecutive seasons. Regarding plant parameters, the results of this study revealed high significant differences between entries on fruit diameter (cm), TSS, number of trichomes/cm2 of leaf, yield of tomato (Ton/Ha) and content of Lycopene, Tannin, Carotene and Ascorbic acid. Tomato accessions HSD11429, HSD6071 and HSD14358 recorded the least percentage of infested leaves/plot, least number of active mines/plot and least percentage of infested fruits/plot while the same accessions were obtained the highest fruit diameters (cm), highest density of trichomes/cm2 of leaves, highest TSS as well as highest yield (Ton/Ha). Accession HSD14358 obtained the highest content of Tannin followed by HSD11429 and HSD6069. Highly negative correlation was observed between the number of trichomes in cm2 of leaves and the percentage of infested plants/plot (-0.8749, < .0001) and also with the mean number of mines/plot (-0.8242, < .0001). TSS was found correlated highly negative with the percentage of infested leaves/plot (-0.82977, < .0001), number of mines/plot (-0.84764, < .0001) and percentage of infested fruits (-0.81465, < .0001) while it correlated highly positive with yield (0.64773, < .0001). Tannin was found correlated moderately negative (-0.5409, < .0001) with the percentage of infested plants/plot. The three elite accessions; HSD6071, HSD11429 and HSD14358, are potent to resist infestation of T. absoluta as well as obtained highest yield among other entries. The mechanism of resistance can be attributed to the density of trichomes, high content of TSS and appropriate percentage of Tannin. According to their resistance characters and yield performance authors would like to recommend the use of the three elite accessions as source of resistance to T. absoluta.

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