Influence of Pre-Sowing Seed Treatments on Vigor and Biochemical Activity in Fresh and Aged Guava (Psidium guajava L.) Seeds

The study titled “Impact of Different Pre-Sowing Seed Treatments on Germination and Seedling Growth of Guava (Psidium guajava L.)” was conducted during 2024–2025 at the Horticulture Laboratory of Shree Guru Gobind Singh Tricentenary University, Gurugram, Haryana, to evaluate the effects of various pre-sowing treatments on germination and seedling growth parameters of fresh and one-year-old guava seeds. Treatments included water soaking (48 hours), hot water soaking (70°C and 80°C for 1 minute), sulphuric acid (10% and 20% quick dip), gibberellic acid (GA₃) at 200 ppm and 400 ppm (24 hours), thiourea at 1000 ppm and 2000 ppm (24 hours), and a control. Parameters assessed included Vigour Index – I and II, speed of germination, accelerated aging test (24, 48, 72, and 96 hours), peroxidase activity, dehydrogenase activity, and electrical conductivity. Results showed that soaking seeds in gibberellic acid (GA₃) at 400 ppm for 24 hours consistently outperformed other treatments, recording the highest Vigour Index – I (205.00 for fresh, 105.67 for aged seeds), Vigour Index – II (11,923.00 for fresh, 7,493.00 for aged), speed of germination (1.88 for fresh, 1.78 for aged), and germination percentages under accelerated aging, alongside the highest peroxidase (710.00 µmol/gm DW for fresh, 640.33 for aged) and dehydrogenase activities (0.23 OD for fresh, 0.18 for aged), and the lowest electrical conductivity (9.43 µS/cm/sample for fresh, 10.08 for aged). The control consistently showed the lowest values across all parameters. Gibberellic acid at 200 ppm and thiourea at 1000 ppm also performed well but were inferior to GA₃ at 400 ppm. These findings demonstrate that pre-sowing treatment with GA₃ at 400 ppm significantly enhances germination, seedling vigour, and seed quality, offering a practical approach for improving guava seedling establishment in nurseries.