Interference of glyphosate-resistant <i>conyza sumatrensis</i> in soybean crops in Central Brazil

Correia, Núbia Maria

doi:10.51694/AdvWeedSci/2023;41:00018

Núbia Maria Correia

Brazilian Agricultural Research Corporation, Embrapa Cerrados, Brasília, Brazil.

http://orcid.org/0000-0002-5045-9798

* Corresponding author: <nubia.correia@embrapa.br>

Conflicts of interest

No conflicts of interest have been declared.

Conflict of Interest: The authors declare that there is no conflict of interest regarding the publication of this manuscript.

Approved by:

Editor in Chief: Carlos Eduardo Schaedler

Associate Editor: Veronica Hoyos

Figures (4)
Tables (4)

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Figure 1
Total weekly precipitation amounts and mean weekly minimum and maximum air temperatures recorded by the meteorological stations of the Embrapa Cerrados from October 01, 2020 to February 28, 2021, and November 01, 2021 to March 31, 2022.

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Figure 2
Adult Sumatran fleabane plants before soybean sowing (a), soybean canopy closure at 60 days after sowing (DAS) (b), and young Sumatran fleabane plants at 60 DAS (c) in the first year.

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Figure 3
Number of adult, dead, and young Sumatran fleabane plants at the end of periods of competition with soybean crops (10, 20, 30, 45, 60, and 116 or 126 days after sowing - DAS), in Experiments 1, 2, and 3, which presented initial Sumatran fleabane population densities of 13, 22 and 23 plants m-2, respectively.

⁽¹⁾ Bars with the same letters, within each competition period, are not significantly different from each other by the Tukey’s test at 5% significance level.

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Figure 4
Dynamics of Sumatran fleabane plants (adult, dead, young) over time at soybean crop in Experiments 1, 2, and 3.

⁽¹⁾ Numbers of adult and dead plants were modeled using the log-logistic equation, and number of young plants using the log-normal function.

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Table 1
Models parameters(1) for prediction of numbers of Sumatran fleabane plants (adult, dead, young) in Experiments 1, 2, and 3

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Table 2
Analysis of variance (F test) for soybean plant population, grain yield per plant, 100-grain weight, total grain yield, weed control, and density of Sumatran fleabane plants at soybean harvest, as a function of periods of competition of soybean with Sumatran fleabane in three experiments with different initial Sumatran fleabane population densities(1)

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Table 3
Analysis of variance (F test) for soybean plant population, grain yield per plant, 100-grain weight, total grain yield, weed control, and density of Sumatran fleabane plants at soybean grain harvest, as a function of treatments (competition periods of soybean crops with Sumatran fleabane plants, and controls) in three experiments with different initial Sumatran fleabane population density(1)

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Table 4
Soybean plant population, grain yield per plant, 100-grain weight, total grain yield, weed control, and Sumatran fleabane plant density at soybean grain harvest as a function of competition periods of soybean crops with Sumatran fleabane plants after the crop sowing and four controls

Experiments	Plant types	Log-Logistic				Log-Normal			Model R²
Experiments	Plant types	Max	Min	b	D₅₀	Mean	Std Dev	Peak Height	Model R²
Experiment 1	Adult	11.48	0	5.34	29.5	-	-	-	0.97**
	Dead	947	0	-1.12	2435	-	-	-	0.99**
	Young	-	-	-	-	3.791	0.307	22.11	0.99**
Experiment 2	Adult	20.83	0	2.22	20.1	-	-	-	0.95**
	Dead	1548	0	-0.73	18293	-	-	-	0.99**
	Young	-	-	-	-	3.657	0.232	23.66	0.99**
Experiment 3	Adult	15.66	0	7.79	45.0	-	-	-	0.79**
	Dead	46714	0	-1.43	11883	-	-	-	0.97**
	Young	-	-	-	-	3.849	0.362	52.90	0.99**

Sources of variation	soybean plant population	Grain production per plant	100-grain weight	Grain yield	Weed control	Weed density
Experiments	0.56	12.18**	4.50*	14.82**	2.50	3.95*
Block (Exp.)	1.47	0.67	0.81	0.23	1.51	0.48
Periods	1.15	0.52	0.89	0.29	0.92	1.78
Exp. x Per.	1.17	0.76	0.76	0.63	0.23	0.68
CV (%)	5.24	11.80	3.61	11.34	2.13	62.59
Experiment	Mean values
Experiment	1,000 plants ha^-1	g	g	kg ha^-1	%	Plants m^-2
First	293.51 a⁽²⁾	11.45 b	16.49 b	3350.58 b	96.46 a	0.61 b
Second	291.74 a	12.76 a	16.99 a	3714.82 a	95.23 a	0.00 a
Third	296.39 a	13.55 a	16.87 ab	4006.68 a	95.44 a	0.45 ab
MSD	10.90	1.01	0.42	292.82	1.42	0.55

Sources of variation	Soybean plant population	Grain production per plant	100-grain weight	Grain yield	Weed control	Weed density
Experiments	0.81	53.33**	11.53**	47.70**	3.63*	4.57*
Treatments	7.58**	21.52**	10.48**	31.34**	192.62**	2.78**
Exp. x Trat.	2.28	3.60	2.66	1.89	1.34	0.99
Block	2.95	2.43	1.31	2.29	1.05	0.53
CV (%)	5.39	11.90	4.87	11.72	12.38	60.90

Competition Periods/Controls⁽¹⁾	Soybean population (1,000 plants ha^-1)	Grain yield per plant (g)	100-grain weight (g)	Total grain yield (kg ha^-1)	Weed control (%)	Weed density (plants m^-2)
0-10	293.54 a⁽²⁾	12.18 abc	16.46 ab	3580.64 a	94.92 a	0.58 ab
0-20	298.82 a	12.49 ab	16.83 ab	3715.71 a	94.71 a	0.82 b
0-30	291.18 a	12.99 a	16.93 ab	3776.41 a	94.38 a	0.38 ab
0-45	289.09 a	12.85 a	16.84 ab	3709.81 a	98.71 a	0.08 ab
0-60	300.56 a	12.34 ab	16.86 ab	3695.08 a	98.00 a	0.07 ab
0-116/126	290.07 a	12.67 a	16.79 ab	3666.52 a	93.54 a	0.19 ab
Control-1	282.78 a	10.43 c	15.89 b	2978.86 b	29.17 b	0.00 a
Control-2	286.94 a	10.73 bc	16.42 ab	3047.58 b	39.17 b	0.00 a
Control-3	287.64 a	12.94 a	16.99 a	3719.70 a	99.08 a	0.10 ab
Control-4	256.11 b	7.03 d	14.54 c	1746.67 c	0.00 c	0.02 a
MSD	20.55	1.84	1.06	522.62	12.17	0.78

[1] * Corresponding author: <nubia.correia@embrapa.br>

Brasil

Brasil

Interference of glyphosate-resistant conyza sumatrensis in soybean crops in Central Brazil

Abstract

Background

Objective

Methods

Results

Conclusions