Pre-Harvest Desiccation in Productivity and Physiological Quality of Cowpea Seeds

摘要

Pre-harvest desiccation is an important strategy to anticipate harvesting, preventing the seed from being left in the field in unfavorable climatic conditions. However, little is known about the use of desiccants and their application times on cowpea (Vigna unguiculata). The objective of this study was to evaluate the effect of desiccant application at different seasons and of desiccant herbicides on productivity and physiological quality of cowpea seeds. Five dessicants were evaluated: paraquat, paraquat sequential application, glufosinate- ammonium, glyphosate with sequential application of paraquat and paraquat + diuron mixture applied in four seasons: 50% of the pods with green coloration and with seeds formed (season I); 70% of the pods in the purple coloration (season II), 90% of the pods in the coloration brown (season III) and 100% of the pods in the coloration brown (season IV), plus a control without the application of desiccants, in which harvesting was performed when 100% of the pods were brown. The number of days of anticipation of harvest, productivity, uniformity test, mass of one hundred seeds, germination and vigor of the seeds were evaluated. None of desiccation strategies affect the physiological seed quality, independent of the application season. The desquaments paraquat, glufosinate-ammonium and the paraquat+diuron mixture, when applied in seasons I and II, provided anticipation of the harvest in up to 13 days and 9 days, respectively, however, the size of the seeds and consequently the productivity were affected.