Synergistic Influence of Seed Scarification and Biopriming Methods in Indigofera tinctoria L. for Enhancing Vegetative Growth Characteristics

Abstract

Biopriming improves crop productivity and quality by enhancing nutrient utilization efficiency and increasing tolerance to environmental stresses. It serves as an economical and environmentally sustainable alternative to conventional chemical seed treatments. The present study evaluated the combined effect of seed scarification and bacterial biopriming methods on vegetative growth of I. tinctoria. The seeds were subjected to dormancy-breaking treatments such as sand scarification, a boiling water dip for one second, and treatment with concentrated sulphuric acid for four minutes, followed by microbial pre-treatments with B. pumilus, B. amyloliquefaciens, B. velezensis, and a consortium of these three bacterial strains. Seeds that did not undergo scarification or bio-priming were maintained as the control. The results revealed that, seeds dipped in boiling water for one second and pre- treated with B. amyloliquefaciens VLY 24 recorded the highest values for plant height (84.51 ± 1.40 cm), number of branches (17.40 ± 0.85), stem girth (2.63 ± 0.02 cm), fresh weight of leaves (24.83 ± 2.76 g/plant), dry weight of leaves (10.61 ± 1.05 g/plant), fresh weight of shoots (58.85 ± 2.05 g/plant), dry weight of shoots (14.60 ± 1.13 g/plant), root length (72.90 ± 4.67 cm), fresh weight of roots (22.65 ± 0.78 g/plant), dry weight of roots (10.36 ± 0.18 g/plant), moderate number of root nodules (80.20 ± 6.51), effective root nodules (69.80 ± 2.55), fresh weight of root nodules (0.30 ± 0.02 g) and dry weight of root nodules (0.10 ± 0.01 g). Coupling thermal scarification with Bacillus sp. optimizes nutrient uptake and growth performance, establishing a highly efficient and sustainable framework for maximizing the productivity of I. tinctoria.