Vol. 9, Issue 7, Part S (2025)

The present investigation entitled “Studies on the Effect of Plant Growth Regulators on Seed Germination and Seedling Growth of Acid Lime (Citrus aurantifolia Swingle)” was carried out during July, 2024 to December, 2024 at the Horticulture Farm, Rajasthan College of Agriculture, MPUAT, Udaipur. The study aimed to evaluate the influence of various plant growth regulators (PGRs) on seed germination behavior, seedling vigour and physiological performance of acid lime, a species known for slow and erratic germination due to its recalcitrant seed nature. The experiment comprised thirteen treatments including combinations of gibberellic acid (GA3), 6-benzyl adenine (BA) and Brassinolide, laid out in a Completely Randomized Design with three replications. Observations were recorded on germination parameters, seedling growth parameters at 60, 90 and 120 days after sowing (DAS) and physiological traits such as chlorophyll content, vigor index and survival percentage. Among the treatments, T₁₃ (GA3 100 ppm + BA 75 ppm + Brassinolide 4 ppm) significantly outperformed all others, recording the minimum days to germination initiation (5.40 days), 50 percent germination (10.00 days) and 100 percent germination (16.30 days), along with the highest germination percentage (88.00%). It also resulted in superior seedling height (15.60 cm), number of leaves (14.00), tap root length (12.00 cm), shoot and root fresh weights (10.00g and 6.40g, respectively), shoot and root dry weights (2.60 g and 1.66 g, respectively), root shoot ratio (0.64) and vigour index I and II (2419.20 and 375.17 g).

Furthermore, the highest chlorophyll content (1.88 mg g-1) and survival percentage (85.40%) were also recorded in this treatment.