Heat Stress Response in Chilli Accessions: A Comparative Analysis

Author(s) : Wardah Kainat, Saba Tabasum, Muneeb Munawar, Naeem Akhtar, Ikram-ul-Haq

Digital object identifier:

https://doi.org/10.52587/JAF060107

Abstract:

Chillies are a key commercial crop grown for vegetables, spices, and value-added products. Heat stress, a major challenge for global crop production, is exacerbated by climate change. The optimal growth temperature for chillies is 20 ‒ 30 °C, but during the summer months (March-June), temperatures exceed this range, often rising above 35°C with low humidity (30-45%). To address this, a field trial was conducted with 21 chilli hybrids under heat stress. Significant differences were observed among the hybrids for several traits. Hybrids such as “V-20” excelled in 1000-SM, while “V-13” had better pericarp thickness and capsule count. “V-14” and “V-16” showed better dry capsule mass. “V11” had superior plant height, fruit weight, and leaf area, while “V12” excelled in capsule length. “V21” had the best primary and secondary root lengths, and “V15” performed best in plant spread. Hybrids “V6,” “V12,” and “V17” had the highest fresh biomass, while “V17,” “V16,” and “V18” had the highest dry biomass under heat stress. Heritability estimates for length-based traits ranged from 0.29 to 0.75, while mass-based traits ranged from 0.24 to 0.46. Capsule length had the highest heritability (0.75), followed by capsule width (0.71). The differential hybrid response was attributed to relative tolerance to abiotic stress. Path analysis revealed that internodal distance significantly influenced fresh capsule mass directly (1.25) and indirectly through capsule width (0.70), leaf area (0.46), and primary root length (0.43).