Compositions and methods useful in identifying and counter-selecting maize plants with having enhanced yield-related traits relative to control plants under abiotic stress conditions such as salt stress and/or drought are provided herein. The methods use molecular genetic markers to identify, select and/or construct salt stress tolerant and/or drought tolerant maize plants. Also provided are methods to enhance tolerance to salt stress and/or drought in crop plants by transforming crop plants with the Zea mays antiporter/sodium ion transporter or by introducing favorable allelic variants of the Zea mays antiporter/sodium ion transporter gene via gene editing.