Influence of NaCl concentration on the growth performance of landraces of rice from Kebbi State, Nigeria

Abstract

Salinity is a major abiotic stress limiting rice production, particularly in semiarid regions. This study evaluated the effects of NaCl-induced salinity on growth performance and ion homeostasis of nine rice landraces from Kebbi State, Nigeria. The experiment was conducted using a completely randomized design (CRD) with five salinity levels: 0, 50, 100, 150, and 200 mM NaCl. Two-weekold seedlings were exposed to salinity for 21 days, after which plant height, root length, leaf number, and tiller count were assessed. Sodium (Na⁺) and potassium (K⁺) concentrations in shoot tissues were determined using flame photometry, and the Na⁺/K⁺> ratio was used to estimate ionic balance. Salinity significantly (P < 0.05) reduced all vegetative parameters. The Na⁺/K⁺ ratio proved to be an effective indicator of salinity tolerance, with tolerant cultivars maintaining lower ratios. Bakin Iri and Jirani Zawara showed superior tolerance with lower Na⁺/K⁺ ratios (0.8 and 0.9 mol·kg⁻¹) and better growth under high salinity. In contrast, Mai Hijabi and CP Guntuwa recorded higher ratios (1.6 and 1.5 mol·kg⁻¹), indicating greater sensitivity. The findings highlight the importance of Na⁺ exclusion and K⁺ retention in salinity tolerance and provide useful information for rice breeding and cultivar selection in salt-affected environments.