Luan Cutti

Growth, phenology, and seed viability between glyphosate-resistant and glyphosate-susceptible hary fleabane

Glyphosate is the herbicide most used worldwide. In cropping systems that rely on repeated applications of glyphosate or cultivate genetically modified soyabean crop, there are numerous cases of glyphosate resistant weeds, including Conyza bonariensis. Differences among competitive ability of Conyza spp. have been found. However, little information is available on the fitness costs related to glyphosate resistance in Conyza bonariensis. We evaluated growth, phenology, and seed viability of glyphosate-resistant (GR) and glyphosate-susceptible (GS) Conyza bonariensis from Brazil, in 2012 (fall/winter) and 2013 (spring/summer). When grown alone, in pots, C. bonariensis GR biotype developed more rapidly than the GS biotype, as evidenced by their earlier bolting, flowering, and seed set. In 2012, GR biotype showed 221.9 cm of plant height compared to 181.1 cm from GS, at the flowering time. In both years, the seed production per plant was superior for GR biotype, showing germination higher than 80% against 66.5% from the GS biotype. Thus, C. bonariensis GR biotype confirmed no fitness penalty also showing characteristics that allow us to infer in superior competitive with the absence of the herbicide. It is important to point out that the biotypes evaluated here have different genetic background and the differences between them may not be fully attributed to the resistance to glyphosate. However, the GR biotype can persist in the environment and outcompete with GS biotypes regardless of further glyphosate selection of pressure.

Tratamento de sementes de Solanum torvum melhora a germinação de maneira dependente do lote

The Solanum genus is a hyperdiverse taxon. There are around two thousand Solanum species worldwide, distributed primarily in tropical and subtropical areas, with a small portion in temperate zones (Edmonds & Chweya 1997). The Solanum torvum species is native to Latin America. It is shrubby, reproduces by seeds and is dispersed mainly by birds that feed on its berries. It is widely distributed in Pakistan, India, Malaysia, China, Philippines and tropical America (Zakaria & Mohd 1994). The species is used both in the pharmacological and agronomic areas, but is little studied and has no methodological ABSTRACT RESUMO