Seed origin and substrate composition affect emergence and early growth of asparagus seedlings

Resumo

The emergence of asparagus seeds is slow and may compromise stand uniformity, being influenced by the physiological quality of the seeds and the composition of the substrate. This study aimed at evaluating the vigor and physiological performance of commercial and locally produced seed lots of Asparagus officinalis, grown in different substrates under greenhouse conditions at the Agricultural Sciences Center, Boa Vista, Roraima, Brazil. In Experiment I, emergence, mean emergence time (MET), and emergence speed index (ESI) of commercial and local seeds were evaluated in a completely randomized design with ten replications. In Experiment II, seedlings obtained from commercial seeds were transplanted into five substrate formulations containing different proportions of Oxisol (Brazilian classification: Yellow Latosol), earthworm humus, and carbonized rice husk. Commercial seeds showed higher final emergence (89.3%) and higher ESI compared to local seeds (68.8%), indicating greater physiological vigor, while MET did not differ between seed sources. The different substrate formulations did not influence root length, number of branches, number of fleshy roots, or number of stems. The initial growth of asparagus seedlings was affected by substrates with balanced proportions between mineral and organic fractions. It is concluded that seed origin directly influences emergence, and that the substrates S₄₀H₄₀CC₂₀, S₃₀H₃₀CC₄₀ and S₂₀H₂₀CC₆₀ favor the initial growth of seedlings.