Physiological quality of bean seeds after application of desiccant herbicides

Abstract

The application of desiccant herbicides in the bean crop is fundamental in the production of quality seeds, since it anticipates the harvesting season, which makes it possible to obtain seeds in the period of physiological maturation, when they are reported with maximum accumulation of dry matter, high vigor levels and germination percentage. However, there is little information about the ideal application time of these products to obtain beans of high physiological quality. Therefore, the objective of this study was to evaluate the physiological quality of bean seeds after application of desiccant herbicides at different times in preharvest. The experimental design was a randomized complete block design in a 2x3+1 factorial scheme, with four replications. Desiccant herbicides paraquat (400g ha-1) and paraquat + diuron (200 + 400g ha-1) were applied in three phenological stages (R8, R8/R9 and R9), plus one control (without herbicide application). Yield (Kg ha-1), mass of one thousand seeds (g), germination (%) and seed vigor were evaluated through tests of accelerated aging, electrical conductivity and primary root length. Application of paraquat molecule at the R8 stage and the paraquat + diuron mixture at the R8/R9 stage reduced the viability and vigor of the bean seeds, and compromised yield. Applications of the paraquat herbicide at the R8/R9 and R9 stages or of the mixture (paraquat + diuron) at the R9 stage preserved the physiological quality of the seeds without;however, affecting yield.

The effectiveness of herbicidal desiccants and application times on seed yield and earliness of soybean

“…Reproductive stage of R7 and later stages produced heavier seed weight (168 g) at application of glyphosate, and diquat at R8 with 168 g. In second year, similar findings were recorded as delayed desiccant application time resulted in increasing seed weight. Toledo et al (2014), Pereira et al (2015), Finoto et al (2017) and Rosado et al (2019) supported the finding that seed weight improved when desiccant application was performed in later growth stages of R6, but significant differences among desiccants. Significant changes in seed yield of soybean were determined according to desiccants and application times.…”

“…The results are in line with the findings of Zagonel (2005), Pereira et al (2015), Finoto et al (2017) and Araújo et al (2018) who found that seed yield was promoted by delayed harvest time and adverse effects of desiccants on the soybean yield were identified. Rosado et al (2019) stated that significant reduction in seed yield of soybean with paraquat application on R8, while Guimarães et al (2012) determined that glyphosate had higher seed yield compared to ammonium glyphosinate and paraquat. Soltani et al (2013) reported that no reduction in dry edible bean yields when desiccants (glyphosate and saflufenacil) were applied at full maturity.…”

Quality of Black Bean Seeds Submitted to Pre-Harvest Desiccation by Different Active Principles and Application Times

“…GERM (Figure 3B) also decreased in later applications, however, for this, a quadratic adjustment was obtained with a minimum technical efficiency point outside the studied range, therefore without an adequate practical explanation. was ceased (MARCOS FILHO, 2005), causing a reduction in yield at the first application time, since 40% of the pods still did not have grains in physiological maturity, characterized as the moment when a seed presents its greatest accumulation of dry matter (ROSADO et al, 2019). Therefore, the results obtained in the present study allow the bean producer to be alerted to a number of aspects that must be taken into account before pre-harvest desiccation is performed.…”

“…Figure1-Length of aerial part, in cm (A) and root length, in cm (B) of the cultivar BRS Esteio, due to the interaction among the desiccants (diquate, glufosinate -ammonium salt, saflufenacil and glyphosate potassic) and desiccation times (60, 70, 80 and 90% of the pods in field maturation), in an experiment conducted in a randomized block design. PatoBranco -PR, 2018/2019 …”

Variability among common bean lines for maximum dry matter accumulation in the grains

“…Other studies have evaluated the use of desiccant herbicides in the common bean crop (Castoldi et al, 2019;Rosado et al, 2019;Silva et al, 2021), but without estimating the percentage of DM accumulation per day until physiological maturation. Moreover, the results do not necessarily provide accurate information on physiological maturation, as the treatment that receives the desiccant herbicide is compared with the control, whose yield will not be affected by the herbicide if the plant has already reached physiological maturity.…”