Studies on Heterosis for Pest and Disease Resistance in Spiny Brinjal

Abstract

Aims: The present investigation was undertaken to estimate standard heterosis for resistance to major insect pests and diseases in spiny brinjal (Solanum melongena L.) and to identify promising hybrid combinations that could serve as parental materials for future resistance breeding programmes. Study Design: A five-parent full diallel mating design excluding selfing was evaluated in a randomised block design (RBD) with three replications. Place and Duration of Study: The experiment was conducted at the Horticultural Farm, Department of Horticulture, Pandit Jawaharlal Nehru College of Agriculture and Research Institute (PAJANCOA & RI), Karaikal, Union Territory of Puducherry, India, during 2024–2026. Methodology: Five genetically diverse parents, namely Illavambadi local (P₁), VRM–1 (P₂), Blue spiny brinjal (P₃), Small spiny brinjal (P₄), and Thar Rachit (P₅), were crossed in a full diallel mating design excluding selfing to produce twenty F₁ hybrids, including reciprocal crosses. The parents and hybrids were evaluated under natural field conditions in a randomised block design with three replications. Shoot and fruit borer infestation, bacterial wilt incidence, and phomopsis blight incidence were recorded following the standard procedures described by Mishra et al. (1988), Hussain et al. (2005), and Meah (2007), respectively. Standard heterosis was estimated over the commercial hybrid Sarpan Hybrid-65. Percentage data were analysed by ANOVA following appropriate transformation. Results: Considerable variation was observed among the parents and F₁ hybrids in resistance to shoot and fruit borer, bacterial wilt, and phomopsis blight. Among the hybrids, shoot and fruit borer infestation ranged from 4.30 to 6.30%, bacterial wilt incidence from 0.40 to 1.60 PDI, and phomopsis blight incidence from 4.80 to 6.70 PDI. Small spiny brinjal × Thar Rachit (P₄ × P₅) recorded the lowest shoot and fruit borer infestation (4.30%) and phomopsis blight incidence (4.80 PDI), whereas Illavambadi local × VRM–1 (P₁ × P₂) recorded the lowest bacterial wilt incidence (0.40 PDI) and matched the commercial check for bacterial wilt and phomopsis blight. The commercial check recorded the lowest shoot and fruit borer infestation and was not surpassed for any resistance trait. Therefore, none of the hybrids expressed desirable standard heterosis over the commercial check. Nevertheless, several hybrids recorded lower pest and disease incidence than the remaining experimental hybrids, indicating their potential value as breeding materials. Conclusion: Small spiny brinjal × Thar Rachit, Illavambadi local × VRM–1, Blue spiny brinjal × Thar Rachit, Thar Rachit × Small spiny brinjal, and Blue spiny brinjal × VRM–1 were identified as promising hybrid combinations among the experimental crosses because of their comparatively lower pest or disease incidence. Although these hybrids did not surpass the commercial check, they may serve as valuable parental materials for developing resistant cultivars after validation across seasons and locations.