International Journal of Plant & Soil Science

The study was conducted in the Horticulture Experiment Field, Department of Horticulture, School of Advanced Agricultural Sciences and Technology, Chhatrapati Shahu Ji Maharaj University, Kanpur, during the year 2026. The primary objective was to evaluate the influence of diverse growing media and plant growth regulators (PGRs), particularly Gibberellic Acid (GA₃) and Naphthalene Acetic Acid (NAA), on the germination behaviour and seedling development of papaya under nursery conditions. The experiment included nine treatments with different combinations of PGRs and media: soil alone (control), soil mixed with vermicompost, Perlite and cocopeat in various proportions, and treated with GA₃ or NAA at 50 ppm. The treatments were assessed for their impact on seed germination, imbibition period, speed of emergence, seedling vigour, survival percentage, and morphological growth attributes such as seedling height, number of leaves, leaf area, root number and length, stem girth, fresh biomass and shoot-to-root ratio. Several germination parameters were recorded, including imbibition period, speed of emergence, germination percentage, seedling vigour index, and survival percentage. Seedling growth parameters such as seedling height, number of leaves, leaf area, stem girth, number and length of roots, fresh weight of shoot and root, and shoot-to-root ratio were evaluated at 30 and 45 days after sowing (DAS). The results revealed significant differences among the treatments. Treatment T4 (NAA @ 50 ppm with soil + vermicompost + Perlite in equal proportions) exhibited the shortest imbibition period (9.00 days), the highest speed of emergence (92.63), and the highest germination percentage (73.33%). It also produced the most vigorous seedlings with a seedling vigour index of 795.67 and the highest survival percentage of 95.83%. NAA treatments, particularly T4, consistently outperformed other treatments in terms of early emergence and uniform germination, due to enhanced enzymatic activity and rapid mobilization of seed reserves. On the other hand, Treatment T8 (GA3 @ 50 ppm with the same media composition of soil, vermicompost and Perlite) was particularly effective in promoting vegetative growth and root development. It recorded the maximum seedling height (15.01 cm), number of leaves (9.40), leaf area (34.37 cm²), root length (12.50 cm), number of roots (21.87), fresh shoot weight (4.20 g), fresh root weight (0.92 g), and shoot:root ratio (4.55). This indicates that GA₃ plays a key role in cell division and elongation, particularly enhancing root biomass and overall seedling establishment. The control treatment (T9), which involved only soil and no growth regulator, consistently showed the lowest performance across all parameters, including germination percentage (51.67%), seedling vigour (331.55), and survival percentage (77.58%), confirming the inadequacy of unamended soil and absence of growth-promoting substances for nursery-level papaya production. In conclusion, the study demonstrates that the integrated use of PGRs and a balanced growing medium significantly enhances papaya seed germination and seedling quality. For nursery managers and papaya growers, the combination of NAA @ 50 ppm with the soil + vermicompost + Perlite media mix (T4) is recommended for achieving superior germination and uniformity, while GA3 @ 50 ppm with the same media (T8) is ideal for enhancing root development and seedling vigour. These findings can serve as a practical guideline for improving the efficiency and success rate of papaya seedling production under nursery conditions.