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.