S03 - Session O1 - Timing and rate strategies for seed priming on parsley transplant production

Authors: Andre da Silva *, Zachary Jones, Wheeler Foshee, Juliano Resende

Seed priming is commonly used to improve parsley seedlings production. The objectives of this study were to characterize the imbibition curve of parsley seeds, to evaluate the effect of priming agents on seedling, to identify priming strategies that improve emergence and vigor of seedlings. A laboratorial experiment characterized the imbibition curve of parsley seeds. Subsequently, three greenhouse experiments were conducted with two cultivars (Krausa and Titan) seeds treated with three priming agents: water (seeds imbibed for 24, 48, 72, and 96 h), polyethylene-glycol 6000 (PEG6000); (seeds imbibed at -0.5, -1.0, -1.5, and -2.0 MPa for 29, 58, 87, and 116 h), and gibberellic acid (GA); (seeds imbibed at 0.5, 1.0, 1.5, and 2.0 g a.i. L -1 of solution for 15, 30, 45 and 60 min). Each priming agent treatment was considered a single experiment, and all experiments were randomized in a complete block design. Seedlings were evaluated for emergence speed index (ESI), total emergence (TE), leaf number (LN), seedling height (SH), root length (RL), aboveground dry biomass (AGB), and root dry biomass (RB). The imbibition curve indicated that phases I, II, and III of germination occurred after 15, 117, and 165 h of seed imbibition. In experiment one, increasing water imbibition timing (IT) reduced ESI on both cultivars; but ESI was higher for Krausa (6.9) compared to Titan (5.4) for water IT of 24 h. TE quadratically reduced with the increase of water IT. In experiment two, TE linearly increased with the increase of IT for cultivar Krausa but not for cultivar Titan, and Krausa (75.5%) had higher TE than Titan (62.75%). In experiment three, ESI and TE increased with the increase of GA concentration. TE and ESI maximized at 5.15% and 72.1%. Strategies for the analysis of best priming were water at 24h IT, PEG6000 at -2.0 MPa at 116h IT, and GA at 2.0 g a.i. L -1 of solution at 15min IT. Once compared to an untreated treatment, seeds had higher ESI for 24 h water IT and PEG6000 at -2.0 MPa for 116 h. There was no significant difference on TE among priming strategies and untreated control.