Exogenous Magnesium Application as a Salinity Mitigator in Cashew Genotypes.

Area of Science:

• Agricultural Science
• Plant Physiology
• Environmental Stress Biology

Background:

• Cashew (Anacardium occidentale L.) is vital economically but threatened by salinity in semiarid regions.
• Salinity negatively impacts cashew growth and physiological functions, limiting cultivation.
• Developing strategies to enhance plant tolerance to salinity is crucial for sustainable agriculture.

Purpose of the Study:

• To investigate the efficacy of foliar magnesium (Mg) application in mitigating salinity stress in cashew seedlings.
• To compare the responses of two cashew genotypes (CCP 76 and AT01) to salinity and Mg treatment.
• To determine the optimal Mg dose for alleviating salinity-induced damage.

Main Methods:

• Greenhouse experiment with two cashew genotypes (CCP 76, AT01).
• Irrigation treatments with two salinity levels (0.5 and 2.5 dS m⁻¹).
• Application of three foliar magnesium (Mg) doses (0, 1, and 2 mL L⁻¹).

Main Results:

• Salinity significantly reduced cashew growth, physiological parameters, and stomatal conductance.
• Foliar Mg application at 1 mL L⁻¹ improved root dry mass, stomatal conductance, CO₂ concentration, and water-use efficiency.
• Genotype AT01 exhibited enhanced tolerance to salinity stress with Mg application, while the 2 mL L⁻¹ Mg dose showed potential toxicity.

Conclusions:

• Foliar magnesium application is an effective strategy to mitigate salinity stress in cashew seedlings.
• The effectiveness of Mg application is dependent on the cashew genotype and the applied dose.
• Genotype AT01 demonstrates superior tolerance to salinity, making it a promising candidate for cultivation in saline areas with Mg supplementation.