Vol. 6, Issue 3 (2017)
Seed priming studies for vigour enhancement in onion CO onion (5)
Author(s): N Saranya, J Renugadevi, K Raja, V Rajashree and Hemalatha G
Abstract: Standardization of priming treatment for onion seeds, to improve the seed vigour under various stress conditions revealed that the seeds primed with 0.5 % ZnSO4 for10 h (nutripriming) was found to enhance the speed of germination (9.9), germination (95 %), dry matter production (20.7 mg) and vigour index (1558) than the unprimed, hydroprimed and sand matrix primed seeds. The evaluation on the anatomical changes in the internal structure of nutriprimed seeds in onion through Scanning Electron Microscope (SEM) revealed that enhanced the cell division and cell elongation at the meristematic tissue of radicle as compared with unprimed seeds. The evaluation on performance of primed seeds under moisture stress conditions, (water holding capacities of 20, 40, 60 and 80 %) revealed that the primed seeds performed better at 20, 40 and 60 % water holding capacities (WHC). The evaluation of primed seeds under different salt concentrations (0.25, 0.5, 0.75 and 1.0 %) to determine the salt tolerance of primed seeds revealed that, seeds primed with 0.5 % ZnSO4 for 10 h could able to tolerate the NaCl salt stress up to 0.75 %. The performance of primed seeds under accelerated ageing condition was found superior over the unprimed seeds. The nutriprimed (0.5 % ZnSO4for 10 h) and hormonal primed (0.2 % methionine for 8 h) seeds attained the 50 % reduction in germination on 9 and 10 days after accelerated ageing, respectively. Whereas the unprimed seeds attained 50 % reduction in germination within 7 days after accelerated ageing.