Plant Volatile Diversity in Different Tomato Genotypes and its Influence on Parasitization Efficiency of Trichogramma chilonis Ishii on Helicoverpa armigera (Hubner)

Evaluation of 15 tomato genotypes (Varieties/hybrids) for their influence on the parasitization efficiency of Trichogramma chilonis Ishii on Helicoverpa armigera (Hubner) eggs under screen house condition revealed significant differences in terms of per cent parasitization. Least parasitization was recorded on Arka Abha (20%) and highest on Arka Ahuti (50%), followed by Anand-1 (46.66%). Olfactory response of T. chilonis to tomato fruit volatiles did not show significant differences. However, leaf volatiles showed significant differences in their attraction to T. chilonis. The fruit volatiles identified from different genotypes comprised 16 compounds, which include alkane hydrocarbons, monoterpenes, sesquiterpenes, diterpenes and other metabolites. It revealed great fruit volatile diversity in terms of number of compounds (qualitative) and their proportions (quantitative). Maximum compounds were identified from variety Ramya and Pusa Ruby (12 each). The major compound present in the fruit volatiles was Linalool-L and its proportionate concentration varied from 1.79 (Pusa Ruby) to 91.12 per cent (Arka Abha). This was followed by heptadecane (present in all the genotypes) and the proportionate concentration varied from 2.89 (A. Saurabh) to 62.9 per cent varalakshmi. The leaf volatile profiles of the genotypes evaluated include 19 compounds. Except genotype varalakshmi in which a-pinene constituted 69.69 per cent of total volatiles, in all other genotypes heptadecane was the main compound and the concentration varied from 21.72 (in Ramya) to 60.75 per cent (in A. Abha). Some of the compounds identified α-phellandrene, a-pinene, trans-caryophyllene, (Z)-α-farnesenc, trans-α-ocimene and selinene are known for their synomonal activity.