Physiological Quality of Pigeonpea Seed after Application of Desiccant Herbicides

Abstract

The pre-harvest application of herbicides may impair seed quality. This way, this paper was conducted to evaluate the effects of the application of desiccant herbicides on the physiological quality of pigeonpea seeds. Six batches of seeds from plants desiccated with glyphosate were evaluated at doses: 1.125 (B1), 1.5 (B2) and 1.875 L &middot ha ^-1 (B3); and Gramocil (20% Paraquat + 10% Diurom) at doses: 1.5 (B4) and 2 L &middot ha ^-1 (B5), and a control which received no application (B6). Seed viability was assessed through the germination standard test, and vigor through the first germination count, accelerated aging, electrical conductivity, seedling length, seedling dry matter and biomass density tests. The experimental design was the completely randomized, with four replications. Data were submitted to variance analysis, and when significant effects were observed, the Scott- Knott test was carried out at 5% probability using the SISVAR 5.1 software. The results showed that: a) the application of 1.875 L &middot ha ^-1 of glyphosate was harmful to pigeonpea seed viability and vigor, evaluated through the accelerated aging test; b) applications of glyphosate in a 1.875 L &middot ha ^-1 dose and Gramocil in 2 L &middot ha ^-1 resulted in low vigor according to the electrical conductivity test of seeds; and c) the seed vigor measured by the first count, seedling length, seedling dry matter and biomass density test was not influenced by the type of desiccant applied.