Effectiveness of Biopriming Using Dark Septate Endophytes in Improving Seed Viability and Early Seedling Growth of Gmelina arborea Roxb. ex Sm.

Gmelina arborea is a fast-growing tree species widely cultivated in plantations and community forests, but the low quality of seeds and seedlings often hampers its cultivation. One way to improve the vigor and viability of declining seeds is through priming. This study aimed to assess the effectiveness of dark septate endophyte (DSE) priming treatment in improving seed germination and seedling growth of G. arborea. Eight priming treatments (control, soaking seeds in Cladosporium teunissimum, Exophiala pisciphila, Cladophialophora nyingchiensis, Diaporthe pandanicola, Cylindroccarpon sp., DSE-consortium, and GA3) were set in a completely randomized design. The treatments significantly (p-value ≤ 0.05) affected germination capacity, germination speed, mean germination time, vigor index, shoot (hypocotyl) length, seedling height, diameter, and sturdiness quotient, but not radicle length or germination value. Soaking seeds in C. teunissimum gave the highest germination capacity (87.25%), followed by soaking in E. pisciphila (85.25%) and DSE-consortium (81.25%). Soaking in C. teunissimum resulted in the highest seedling height with an increase in control of 7.6%, while the DSE consortium produced the highest diameter with an increase in control of 10.7%. These findings support the application of DSE-based seed treatments as a promising, sustainable approach to improving seed quality and establishing plantations and community forests.