Physiological Quality of Carioca Bean Seeds Submitted to the Application of Desiccant Herbicides in Two Periods

C.T Castoldi,L.L Radunz,C.T Forte,L Galon,M.A Scariot,D.O Souza,I Aspiazú

doi:10.1590/s0100-83582019370100154

Abstract

ABSTRACT: The use of herbicides for bean crop desiccation aiming seed production, is an alternative management because it allows harvesting when the seeds present high vigor, germination and dry mass, however this technique can cause damages to the seeds. The objective of this study was to evaluate the physiological quality of bean seeds, of the Carioca type, with the application of desiccant herbicides doses at different periods, aiming at the anticipation of the harvest. The bean plants, Pérola cultivar, were desiccated when the seeds had 42 and 30% water content, with ammonium glufosinate, saflufenacil and diquat at doses of 0, 50, 75 and 100% in relation to the recommended average dose for desiccation, respectively for each of the herbicides. The control treatment without desiccant application was harvested on the same date as desiccation. The additional treatment, also without desiccant application, was harvested only when the seeds had a water content of 18%. The variables analyzed were germination, first germination count, germination speed index, cold test, accelerated aging, seedling and radicle length, and dry mass. The herbicides applied in the first period (42% water), at the highest doses, impair the physiological quality of the seeds, and the seeds with water contents of 30 and 42%, without the use of desiccants, promote high vigor and germination. Satisfactory results were obtained when the saflufenacil herbicide was applied in period 2 (30% water), using 50% of the recommended average dose of this herbicide.

Highlights

Harvesting bean seeds (Phaseolus vulgaris L.) at the right time is one of the factors that most contribute to high yield (Franco et al, 2013)
The research was conducted at the Universidade Federal da Fronteira Sul (UFFS), Campus Erechim
The area used for bean sowing was previously desiccated with the glyphosate herbicide at a dose of 1,440 g ha-1

Summary

Introduction

Harvesting bean seeds (Phaseolus vulgaris L.) at the right time is one of the factors that most contribute to high yield (Franco et al, 2013). To obtain a crop with high productive potential, it is necessary to value quality seed with high vigor and germination and maximum dry mass accumulation (Santos et al, 2005). These characteristics are present, with greater evidence, in the physiological maturity of seeds, which is considered the ideal time for harvesting (Guimarães et al, 2012). According to Silva et al (2009), the physiological maturity corresponds to the stage in which the plants present yellow leaves, with most of the pods dried and the seeds in their maximum development At this stage, bean seeds have high water content and plants still have large numbers of leaves and green branches, making mechanized harvesting difficult (Coelho et al, 2007). Increasing percentages of tegument cracking and wrinkling, easier pathogen penetration, and greater exposure of the embryonic tissue to the environment are factors related to climatic conditions, increasing the deterioration process and compromising its quality (Marcandalli et al, 2011), and may even culminate in total loss

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