Enhancing drought resilience in grass pea through arbuscular mycorrhizal fungi and rhizobium symbiosis

Abstract A 2‐year experiment was conducted to evaluate the efficiency of Rhizobium bacteria and arbuscular mycorrhizal fungi in improving the growth and yield‐related traits of grass pea ( Lathyrus sativus L.) under different irrigation regimes (well‐watered, mild water stress, and severe water stress). The results showed that unfertilized and water‐stressed plants had the lowest performance, while plants inoculated with bioinoculants exhibited the best growth and yield. Water limitation led to a reduction in total chlorophyll content (20.3%), leaf area index (20.32%), relative water content (5.5%), seeds/pod (2.9%), pods/plant (20.23%), 1000‐seed weight (2.92%), pod harvest index (0.72%), seed yield (24.5%), and biological yield (17.69%) compared to the well‐watered treatment over 2 years. Rhizobium inoculation enhanced relative water content, seeds/pod, 100‐seed weight, biological yield, and pod harvest index by an average of 9.25%, 4.82%, 4.81%, 16.78%, and 1.36%, respectively. Similarly, arbuscular mycorrhizal fungi inoculation increased relative water content (7.7%), seeds/pod (3.8%), 1000‐seed weight (3.9%), pod harvest index (1.04%), and pod partitioning index (13.9%). These findings suggest that applying a combination of bioinoculants from different microbial groups can be an effective strategy for enhancing the productivity of grass pea under water‐limited conditions.