Abstract

IBANHES NETO, Helio F. et al. Germination and initial growth of crops and weeds in response to Digitaria insularis aqueous extracts. Rev. de Ciências Agrárias [online]. 2020, vol.43, n.1, pp.32-56.  Epub Mar 01, 2020. ISSN 0871-018X.  https://doi.org/10.19084/rca.18659.

The objective of this study was to evaluate the allelopathy of aqueous Digitaria insularis (sourgrass) extracts on germination and initial growth of cultivated plants and weeds. Three factorial experiments (3x2x3) were carried out, being factor A - the tested plant species: crops - Glycine max (soybean), Zea mays (corn), Phaseolus vulgaris (bean), and weeds - Digitaria horizontalis, Echinochloa crusgalli and Bidens pilosa ; factor B - extracts of roots and shoots of sourgrass and factor C - concentration of the extract - 0, 50 and 100%. Germination percentage and the length of shoots and roots of the tested species were evaluated. Among the crops, there was a reduction in germination only in bean (-12.5%) in response to 50% of the aqueous root extract. The initial development of corn and beans were hampered. No negative effects were observed on soybean. Among the weeds, the most sensitive species was Bidens pilosa, with reductions in germination (-41%), length of shoots (-59%) and root (-84%) when the seeds were exposed to the 100% of the shoot extract of the sourgrass. The other weed species also suffered reductions in at least one of the evaluated variables. Therefore, the allelopathic effect exerted by sourgrass extracts may be related to its great competitiveness with crops, as well as to its dominant character in areas after its introduction.

Keywords : Allelopathy; sourgrass; interference; invasiveness; phytotoxicity..

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