Influence of AMF Inoculation on Germination Dynamics and Seedling Traits of Swietenia macrophylla
Shiran K *
College of Forestry, Kerala Agricultural University, Thrissur, Kerala 680 656, India and ICAR-Central Arid Zone Research Institute, RRS, Jaisalmer, Rajasthan, 345001, India.
Santhoshkumar, A.V.
College of Forestry, Kerala Agricultural University, Thrissur, Kerala 680 656, India.
Binu N Kamalolbhavan
College of Forestry, Kerala Agricultural University, Thrissur, Kerala 680 656, India.
Kunhamu TK
College of Forestry, Kerala Agricultural University, Thrissur, Kerala 680 656, India.
Ashwath M N
College of Forestry, Kerala Agricultural University, Thrissur, Kerala 680 656, India and College of Agriculture, Gangavathi, University of Agricultural Sciences, Raichur, Karnataka -583 227, India.
*Author to whom correspondence should be addressed.
Abstract
Background and Aim: Production of quality planting material (QPM) is a major constraint in forestry, where enhanced germination and early seedling vigor is critical for nursery success. Arbuscular Mycorrhizal Fungi (AMF) are widely recognized for improving nutrient uptake, stress tolerance, and growth in many crops, but their role in tree seedling establishment remains variable. This study evaluated the influence of AMF inoculation on germination and early growth of Swietenia macrophylla (mahogany).
Methodology: Mahogany seeds were sown in a coir pith + farmyard manure (FYM) substrate, either uninoculated (Control) or inoculated with a consortium of Glomus mosseae, G. etunicatum, and G. fasciculatum. Germination parameters were monitored daily for 90 days, and destructive seedling traits (leaf, shoot, root, biomass, and leaf area) were assessed thereafter. Data were analyzed using Welch’s t-tests for germination traits and Student’s t-test for seedling traits, depending on distribution and variance assumptions.
Results: Results showed that AMF did not significantly alter final germination percentage (Control = 0.693; AMF = 0.674; p = 0.756). However, germination kinetics were affected: mean germination time increased (29.6 vs. 32.2 days; p = 0.005), mean germination rate decreased (0.034 vs. 0.031; p = 0.014), and the coefficient of velocity of germination was lower in AMF (3.38 vs. 3.10; p = 0.005), indicating slower and less synchronous emergence. In contrast, seedling growth parameters viz. total leaflets, shoot and root length, stem girth, biomass allocation, root volume, and leaf area—showed no significant differences between treatments (all p > 0.05).
Conclusion: These findings suggest that under coir–FYM substrate, AMF inoculation delayed germination without enhancing early seedling growth, likely due to poor colonization. Results highlight the importance of substrate choice, inoculum placement, and nutrient environment in achieving effective AMF establishment. Inoculation benefits may vary with substrate conditions and techniques, emphasizing the need for optimized methods in forestry nurseries. Thus, in mahogany, AMF benefits may be realized only under refined inoculation protocols or at later developmental stages.
Keywords: Swietenia macrophylla, arbuscular mycorrhizal fungi, context-specific responses, germination kinetics, seedling growth, nursery management