Impact of Salinity Stress on Ion Homeostasis of Some Selected Groundnut (Arachis hypogaea L.) Varieties

Abstract

Groundnut (Arachis hypogaea L.) is one of the most important leguminous crops in Africa. Nigeria is the largest groundnut producing country in West Africa. Salinity stress is one of the major abiotic constraints hindering groundnut production. This study was carried out to analyze the impact of salinity stress on ion homeostasis of some selected Groundnut varieties. Ten groundnut varieties (Samnut 22, 23, 24, 25, 27, 28, 29, Bahaushiya, Maibargo and Kwankwasiyya) were collected from Center for Dryland Agriculture (CDA) Bayero University, Kano. The groundnut varieties are planted and irrigated with four different concentrations of salt-water solutions (0 dsm/m², 3.5 dsm/m², 6.5 dsm/m² and 9.5 dsm/m²) for three months. The varieties treated with 9.5 dsm/m² was observed to record significantly higher Na⁺ and lower K⁺ concentrations, while Na⁺/K⁺ ratio was observed to be higher with the increase in salinity concentration. Maibargo consistently exhibited low Na⁺ concentrations across all salinity levels, indicating effective Na⁺ exclusion mechanisms. However, its K⁺ concentration dropped significantly under salinity stress, suggesting that its tolerance is primarily due to Na⁺ exclusion rather than K⁺ retention. Kwankwasiyya maintained high K⁺ concentrations under salinity stress, indicating strong K⁺ retention mechanisms. Samnut 23 and Samnut 29 accumulated high Na⁺ concentrations and showed significant reductions in K⁺ concentrations, indicating poor ion homeostasis. The study demonstrated that salinity stress significantly increased Na⁺ concentration, Na⁺/K⁺ ratio and reduced K⁺ concentration. Varietal differences played a crucial role in determining tolerance to salinity, with Maibargo and Kwankwasiyya showing the most promise for cultivation under saline conditions.