Hydropriming and substrates affect the emergence and production of Calendula officinalis L. seedlings.

In order to establish protocols that can contribute to the propagation of medicinal plants, this study evaluated the effect of hydropriming and substrates on the emergence and production of Calendula officinalis L. seedlings. Seeds were submitted or not to hydropriming for 24 hours, and subsequent sowing in four substrates: S1) 100% Dystroferric Red Latosol -- DRL, S2) DRL + coarse sand (1:1 v/v), S3) DRL + Tropstrato® commercial substrate (1:1 v/v) and S4) 100% Tropstrato®, and kept in greenhouse with 50% shading. Higher emergence percentage in substrates with the presence of DRL was observed. Seed hydropriming impaired seedling emergence, but contributed to root growth, biomass production and seedling quality. The 100% Tropstrato® substrate favored higher dry mass production and seedling quality. Positive linear correlation (≥ 0.70) was observed between shoot and root growth characteristics with biomass production and Dickson's quality index. Principal component analysis explained 78.95% of the experimental variance, excluding the first count and the shoot/root ratio with low representativeness. In the cluster analysis of Euclidean distances, seedlings with the greatest similarity were those produced with 100% DRL and DRL + Tropstrato® with and without hydropriming, respectively. Dystroferric Red Latosol is recommended pure or combined with Tropstrato® for the production of C. officinalis L seedlings, and the hydropriming impaired seedling emergence characteristics. [ABSTRACT FROM AUTHOR]