Stability of Bottle Gourd (Lagenaria siceraria (Mol.) Standl.) Genotypes for Growth and Earliness Traits Under Different Nitrogen Environments

Abstract

Aims: The present investigation aimed to evaluate the mean performance and stability of thirteen bottle gourd [Lagenaria siceraria (Mol.) Standl.] genotypes for important vegetative growth and earliness traits under three nitrogen-induced environments. Study Design: Thirteen genotypes were evaluated under three nitrogen levels representing experimental environments. Place and Duration of Study: The experiment was conducted at Haveli Farm, College of Horticulture, Bagalkot, Karnataka, India, during the Rabi season of 2018–19. Methodology: The thirteen genotypes were evaluated under nitrogen levels of 50, 62.5 and 75 kg N ha⁻¹. Observations were recorded for vine length, number of primary branches and number of leaves at different growth stages, together with days to first female flower, node bearing the first female flower and days to first harvest. Genotype × environment interaction and stability parameters were assessed using the regression approach of Eberhart and Russell, involving genotype mean performance, regression coefficient (bᵢ) and deviation from regression (S²dᵢ). Results: Considerable variation was observed among the genotypes for vegetative growth and earliness traits. Bottle G-7 recorded superior mean performance for vine length, number of primary branches and number of leaves at the evaluated growth stages. It also recorded the earliest first female flower (49.25 days) and earliest first harvest (59.67 days). Pusa Naveen recorded the lowest node bearing the first female flower (7.00), indicating early reproductive development for this specific character. The stability analysis demonstrated differential genotype responses across the three nitrogen environments. Bottle G-2, Arka Bahar, Samrat and Kolkatta Local also exhibited favourable performance for selected traits. Conclusion: The study revealed substantial genotypic variation for vegetative growth and earliness under different nitrogen levels. Bottle G-7 emerged as the most promising genotype for the combined improvement of vegetative vigour and early crop development under the conditions evaluated. However, the experimental environments represented nitrogen levels at a single location and during one season; therefore, broader adaptation should be confirmed through additional multi-location and multi-season studies.