Role of different trichome style in the resistance of various tomato genotypes to tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in greenhouse condition
The tomato leaf miner (TLM), Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is one of the major pests that attacks commercial tomato. TLM is becoming resistant to many of the pesticides used in the tomato fields. A potential alternative method of control is host plant resistance, which may be mediated by glandular and non-glandular trichomes. We studied glandular and non-glandular trichomes potentially related to tomato resistance of nine tomato genotypes (Lycopersicon hirsutum Humb & Bonpl), extensively cultivated in western Iran. The antixenosis and/or antibiosis effect of the genotypes including Mobil, Falat 3, Cal J N3, Dehghan, Super Strain B, Rio grande, King Ston, Early Urbana, and Peto Mech were evaluated under laboratory conditions (25 ± 1°C, 65 ± 5% R.H. and a photoperiod of L16: D8 h). In antixenosis assay, preference was highest on Mobil and lowest on Rio grande and King Ston. In antibiosis assay, TLM elicited the lowest egg-laying response on Peto Mech, Rio grande and King Ston; and the highest one on Falat 3 and Dehghan genotypes. Also King Ston and Mobil genotypes allowed the lowest and highest larvea density on the leaves, respectively. Trichome type and density of the assayed genotypes appeared to be related to TLM population density: the most infested genotype (Mobil and Cal J N3) displayed the lowest style IV and VI trichome ranks of leaf blade, vein and domatia (glandular trichomes). Significant negative relations were found between egg and larvae density with leaf I style trichome; and also larvae and adult density with IV and V style trichome. Finally, current experimental screened preliminary a two of genotypes (Rio grande and King Ston) quite promising for developing resistance programs against TLM.
