Growth, yield, and salt tolerance of tomato genotypes as influenced by plant growth regulators under saline-sodic soil conditions in Kano, Nigeria

Abstract

Salinity and sodicity are major constraints limiting tomato production in irrigated semi-arid regions of Nigeria. A field experiment was conducted during the 2020 and 2021 dry seasons at the Kano River Irrigation Scheme to evaluate the response of tomato genotypes to selected plant growth regulators under saline-sodic soil conditions. The treatments consisted of four tomato genotypes (F1 Anaya, F1 Mona, F1 Thorgal, and Roma VF) and four plant growth regulator treatments (control, potassium silicate at 16 g L⁻¹, salicylic acid at 130 mg L⁻¹, and tamarind extract at 8%) arranged in a split plot design with eight replications. Plant growth regulators were assigned to the main plots, while genotypes were allocated to the subplots. Data were collected on growth and yield parameters and subjected to analysis of variance using GenStat and SAS statistical packages. The results revealed significant varietal differences in plant height, leaf area, marketable fruits, and fruit yield during both seasons. Salicylic acid significantly improved fruit yield, producing the highest yields of 5 057 and 14 607 kg ha⁻¹ during the 2020 and 2021 seasons, respectively. Among the genotypes, F1 Mona and F1 Thorgal exhibited superior growth and yield performance under saline-sodic conditions. Significant interaction effects were observed between plant growth regulators and genotypes for marketable fruits, non-marketable fruits, and fruit yield. F1 Thorgal combined with salicylic acid produced the highest fruit yield (17 542 kg ha⁻¹) during the 2021 season. The study concluded that salicylic acid in combination with F1 Mona and F1 Thorgal can effectively enhance tomato productivity under saline-sodic conditions in the Sudan Savanna of Nigeria.

Keywords: abiotic stress tolerance; phytohormones; foliar application; saline-sodic soils; osmotic adjustment; irrigated agriculture