| Abstrakt: |
Leafhoppers pose a significant threat to cotton production and leading to substantial losses when susceptible hybrids and improper insecticidal treatments are employed. Developing cotton cultivars with leafhopper resistance is crucial in mitigating this issue. In this study, we evaluated eighteen genotypes, including parental lines, F1 hybrids, and standard checks, during the Kharif 2022. The assessment was conducted in both field and polyhouse environments over a crop period from 30 to 120 days. Our findings revealed that parents, NDLH1938 and Suraksha, and three F1 hybrids TVH002 × Suraksha, NDLH1938 × Suraksha, and TVH002 × NDLH1938 exhibited significant resistance (p ≤ 0.05). They exhibited lower leafhopper populations, injury and susceptibility indexes, and host preference survival rates compared to the other genotypes. Stereo and field emission scanning electron microscopy (FESEM) unveiled the presence of glandular trichomes (GTs) and single-celled non-GTs with 2-8 branches on primary stem leaves. Trichomes rate increased upward on new leaves, establishing a negative correlation (trichome length r = -0.52, density r = -0.72) with leafhopper population. Additionally, morpho-biochemical traits such as reducing sugars, leaf thickness, chlorophyll, amino acids, and proteins were positively associated with pest density. Energy dispersive X-ray (EDS) spectroscopy indicated that high-field resistant hybrids had lower elemental composition. Furthermore, genotypes with higher gossypol and tannin levels experienced lower leafhopper infestations, suggesting that these compounds which may act as feeding deterrents. The study highlighted that a combination of various morpho-biochemical traits governs high-level resistance (R² = 0.98), rather than a single factor. These identified resistant genotypes can play a pivotal role in future breeding programs aimed at enhancing leafhopper resistance in cotton. [ABSTRACT FROM AUTHOR] |
