CHEMICAL DESICCANTS FOR ANTICIPATION OF HARVEST AND PHYSIOLOGICAL QUALITY OF COWPEA SEEDS

Elizeth Regina Raisse,Miquéias De Oliveira Assis,Roberto Fontes Araujo,Eduardo Fontes Araujo,Francisco Cláudio Lopes De Freitas

doi:10.1590/1983-21252020v33n402rc

Abstract

ABSTRACT Information about the effect of herbicides on cowpea seed quality is scarce. The objective of this work was to evaluate the effect of using chemical desiccants at pre-harvest on the anticipation of harvest and physiological quality of cowpea seeds of the cultivar BRS-Tumucumaque, before and after storage. Two experiments were conducted: experiment 1 was conducted under a randomized block design, with four replications; the treatments consisted of seven herbicides (carfentrazone-ethyl, saflufenacil, glyphosate, paraquat, flumioxazin, glufosinate-ammonium, and diquat) and a control treatment; anticipation of harvest, and seed water content, germination, and vigor were evaluated. The seeds were stored for six months in controlled environment and not-controlled environment rooms and evaluated for water content, germination, and vigor in Experiment 2, which was conducted in a 7^2+1 factorial arrangement, with four replications; the first factor consisted of the seven herbicides, the second factor was the two storage environments, plus a control treatment. The results showed 3 to 9 days of anticipation of harvest relative to the control. The glufosinate -ammonium herbicide negatively affected seed germination and vigor. The glyphosate herbicide decreased seed germination and vigor after storage. The physiological quality of cowpea seeds at the post -harvest period and after six months of storage was not affected by the carfentrazone-ethyl and flumioxazin herbicides. Paraquat and diquat were the most efficient herbicides for the anticipation of harvest (nine days). Glyphosate and glufosinate -ammonium were the most harmful herbicides to seed physiological quality. The controlled environment room was the most adequate environment for seed conservation.

Highlights

Cowpea [Vigna unguiculata (L.) Walp] is a legume species native to West and Central Africa that was introduced to Brazil in the mid-16th century
The use of pre-harvest desiccation enables the anticipation of harvest of cowpea seeds
Flumioxazin, saflufenacil, and glufosinate-ammonium herbicides anticipated the harvest in 6 days

Summary

Introduction

Cowpea [Vigna unguiculata (L.) Walp] is a legume species native to West and Central Africa that was introduced to Brazil in the mid-16th century. Cowpea crops have been expanded to specialized agricultural regions of the country, especially the Central-West, where they started to be grown at large scale in 2006 (FREIRE FILHO et al, 2017). This expansion was due to the development of varieties with early and uniform maturation cycles for mechanized crop systems, and breeding for high grain quality (ROCHA et al, 2017). The expansion of the planting area and the development of technologies for cowpea crops increased the demand for high quality seeds, since it is essential for a successful establishment of the crop in different environmental conditions. Mechanized harvest is technically and economically unviable because cowpea seeds present approximately 54% water content at this point (NOGUEIRA et al, 2014) and are not suitable for mechanized harvesting because of the high number of plants with green leaves and stems

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Conclusion