Physiological and Photosynthetic Variability among Tomato (Solanum lycopersicum L.) Genotypes under Pot Culture in Temperate Kashmir

Abstract

The present study was conducted to assess genotypic variability in growth, biomass allocation, photosynthetic pigments and leaf gas-exchange characteristics of twelve tomato genotypes under pot culture conditions in the temperate climate of Kashmir. The experiment was conducted during 2018 and 2019 at Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Shalimar, using a completely randomized design with four replications. Significant differences were observed among genotypes for plant height, shoot and root dry weight, shoot/root ratio, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, net photosynthetic rate, transpiration rate and stomatal conductance. Among the genotypes, 2016/Todvar-9 exhibited the highest plant height (82.13 cm), root dry weight (3.03 g plant⁻¹), chlorophyll a (1.28 mg g⁻¹ FW), chlorophyll b (1.04 mg g⁻¹ FW), total chlorophyll (2.32 mg g⁻¹ FW) and carotenoids (0.32 mg g⁻¹ FW). It also recorded the highest net photosynthetic rate (18.57 µmol CO₂ m⁻² s⁻¹), transpiration rate (2.08 mmol H₂O m⁻² s⁻¹) and stomatal conductance (237.10 µmol H₂O m⁻² s⁻¹). Genotypes 2016/Todvar-7 and 2016/Todvar-10 also exhibited relatively higher physiological activity, whereas 2016/Todvar-2 and 2016/Todvar-3 generally recorded lower values. The results demonstrate substantial genotypic variability in physiological and photosynthetic attributes, with 2016/Todvar-9 showing superior overall physiological performance under the experimental conditions. This genotype warrants further evaluation for yield and adaptation under temperate conditions of Kashmir and for potential use in tomato improvement programmes.