Abstract

This study explored the auxin–cytokinin activity of combined soybean radicle and red shoot extracts to enhance rooting and induce resistance in red dragon fruit (Hylocereus polyrhizus) cuttings. A factorial randomized complete block design was used, involving nine treatment combinations of different extract concentrations. GC–MS profiling confirmed the presence of phytohormones including indole-3-acetic acid (IAA) and zeatin-type cytokinins in both extracts. The treatment combining 100% soybean radicle with 50% red shoot extract (K1P2) showed the highest root number (8.67), while 50% soybean radicle alone (K2P0) resulted in the longest root length (21.85 cm). Root biomass, both fresh and dry, was significantly increased under combined extract treatments, especially K1P2. Root Discoloration Index analysis indicated improved disease resistance, with several treatments reaching the “resistant” category. These results highlight the potential of natural, hormone-rich plant extracts as sustainable biostimulants for improving vegetative propagation and defense response in red dragon fruit cultivation.