Seletividade do aleloquímico Piplartina para a cultura da soja

Abstract

Soybean is the most prominent commodity in Brazil, with very significant increases in productivity in recent years. The higher yields involves phytosanitary threats, among which a complex scenario of growing infestations of weeds, stands out herbicide resistant and tolerant weed biotypes,. Allelopathy appears as a promising option in the search for new molecules of natural origin, whose potential can be used in programs for the management of weeds that are difficult to control. Derivatives of Piper tuberculatum, including piplartine, have already demonstrated efficiency in controlling weeds of great agricultural importance. In this study, experiments were carried out to determine the influence of piplartine on germination and development of soybean plants, cultivar TMG 2757 IPRO, as well as the selectivity of this allelochemical in pre- and post-emergence applications on the same cultivar. In the germination experiment, the speed index and mean time of germination, radicle and hypocotyl length, as well as the percentage of normal, abnormal and dead seedlings were determined. In the pre-emergence experiment, the percentage of emergence, the speed index and the average emergence time were determined. Both in pre and post-emergence experiments were evaluated plant height, shoot length, number of leaves, phytotoxicity and fresh and dry matter of shoots and roots. In the germination bioassay, there was no negative influence of piplartine on the germination and development of soybean seeds. In pre-emergence, the negative results were practically null, being the only variable affected the fresh mass of the root, however not differing from the control. In post-emergence, the interference of piplartine on soybean development was very low, as the decrease caused by some doses did not differ from the control without piplartine application. Therefore, the selectivity results of piplartine for the soybean crop were very promising.