Study on root architecture of tropical chili peppers (Capsicum frutescens) inoculated with arbuscular mycorrhizal fungi

<h2>Abstract</h2> The increasing biotic and abiotic stress on crop growth and development adversely affects crop productivity. Arbuscular Mycorrhizal Fungi (AMF) have garnered significant attention as an eco-friendly management technique, demonstrating multifaceted capabilities for enhancing crop growth and yield by facilitating essential nutrients and improving root structure. However, AMF colonization is influenced by the root characteristics of the host plant and its responsiveness to AMF. Here, we investigated the potential correlation between AMF colonization and seedling root anatomy and their effects on the root architecture of 50 tropical chili pepper genotypes at the mature stage. Root anatomy was observed in 30-day-old seedlings, while AMF colonization, growth response, root morphology, and architecture were assessed in 10-week-old plants post-transplantation. Our results revealed significant positive relationships between the width of the seedling root cortex and the percentage of AMF colonization (P < 0.001), as well as genotype responsiveness to AMF (P < 0.005). The width of the root cortex ranged from 111.96 to 213.50 μm in the responsive genotypes and from 29.40 to 95.93 μm in the unresponsive genotypes. Higher AMF colonization was observed in genotypes with a thicker root cortex. The morphology and architecture of roots improved significantly due to AMF symbiosis, with more pronounced improvements in the responsive chili pepper genotypes. These findings highlight the significance of root anatomy in promoting AMF colonization and underscore it as a key target in plant breeding and improvement for environmentally friendly tropical chili pepper cultivation. The potential for AMF to mitigate the effects of biotic and abiotic stress on crop sustained growth and productivity.