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Excessive nitrogen application predisposed biometric traits of heat tolerant tomato (solanum lycopersicum) genotypes to environmental interaction

Year: 2025
Type: article
Abstract: This study assesses the effects of Nitorgen (N) application on growth, genetic variability on yield, and environmental interactions in heat-tolerant tomato genotypes in Savannah of Nigeria. Three tomato genotypes; Icrixina, Roma VF, and UC82 were tested across four N levels: 0, 50, 100, and 150 kg ha⁻¹ at two agro-ecologically distinct sites: Bayero University Kano (BUK) and the National Institute for Horticulture, Bagauda Research Station. Analysis of variance (ANOVA) showed significant effects (p < 0.05) of N levels on biometric traits: plant height, leaf area retention, and chlorophyll stability index (CSI) with Icrixina exhibited a 38.10% increase in height growth rate at 150 kg N ha⁻¹ (BUK), while leaf area loss decreased from 198.96 cm² at 0 kg N ha⁻¹ to 48.60 cm² at 150 kg N ha⁻¹ higher than RomaVF that saw a decrease in LA loss from 198.96 to 44.40 and a reduction in senescence rate from 99.50% to 22.20% as N increased from 0 to 150 kg/ha. The UC82B genotype exhibited high flower abortion and senescence rates, with values significantly reducing only at higher N levels. Yield analysis revealed significant genotype-environment (GxE) interactions, with the highest yield of 15,300 kg ha⁻¹ recorded for Icrixina at Bagauda under 150 kg N ha⁻¹ (p < 0.01) while UC82B possessed the least. Genotypic variance (σ²g = 0.2667) and phenotypic variance (σ²p = 0.4) estimates indicate high heritability (H² = 0.67) for yield traits, suggesting strong selection potential for N use efficiency (NUE). Genetic advance as a percentage of mean (GAM) was 17.44% at BUK and 18.31% at Bagauda, underscoring the potential for genetic improvement in NUE and heat resilience. This study highlights Icrixina and Roma VF as high-yielding, N-efficient genotypes suitable for heat-stressed environments, reinforcing the need for breeding programs focused on NUE and heat tolerance to ensure tomato productivity under climate change pressures.
Authors: Zakari, S. A., Aliyu, K. T., Manga, A. A., Nuhu, A. A., Sani, F. K., Galadanci, N. I., Labaran, H. B., Haruna, S. U., Ahmed, A. U., Idris, J. A
Language: English
Subfield: Plant Science
Open Access status: green
OpenAlex ID: W6957853859
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