Abstract <p>The aim of this experiment is to investigate the external application of proline in mitigating the adverse effects of drought stress and to select the superior genotype of clover in terms of resistance to this stress. The experiment was conducted over a two-year period during the 2020–2021 and 2021–2022 cropping seasons, utilizing a split-plot randomized complete block design with three replications. Three levels of irrigation, five clover genotypes and three levels of proline were used as the experimental factors. Of the various genotypes investigated, Persian clover (<i>Trifolium resupinatum</i>) demonstrated the highest capacity for fodder yield (4.98 t/ha), chlorophyll <i>a</i> (1.41 mg/g fr wt), chlorophyll <i>b</i> (0.737 mg/g fr wt) under distinct levels of deficit irrigation and proline foliar application. Furthermore, <i>T</i>. <i>hirtum</i> L. evinced the most elevated proline value (8.04 mg/g fr wt) when subjected to the deficit irrigation treatment and 200 mM proline foliar spraying. Of the stress indices evaluated, mean productivity (MP), harmonic mean (HM), geometric mean productivity (GMP), stress tolerance index (STI), and yield index (YI) evinced the strongest correlation with dry matter yield under normal, mild, and severe stress conditions. The findings of this study underscore the potential benefits of proline foliar application for enhancing forage production in arid and semi-arid regions, with clover genotypes exhibiting greater potential for yield improvement when subjected to this treatment.</p>