Pre-harvest desiccation in order to minimize the time of exposure to abiotic factors after physiological maturity is a practice used in the production of quality seeds. The aim of this work was to evaluate the physical, physiological and sanitary quality of wheat seeds from plants that received non-selective herbicide application at pre-harvest. For this, the treatments were applied on pre-harvest culture. A completely randomized design was applied. We use the herbicides ( glufosinate-ammonium , glyphosate and paraquat ), phenological stages of herbicide application (Z-83, Z-85, Z-87, Z-92) and additional treatment (without application). The routine tests that express the physical, physiological and sanitary integrity of seeds were evaluated. For herbicide treatments, there was an 8% and 26% reduction in germination under laboratory conditions for BRS Parrudo and Sinuelo, respectively. Soil emergence was 14% higher for the control treatment, not statistically different for the Z-87 and Z-92 stages and also for the herbicides glufosinate-ammonium and glyphosate for both cultivars. The application of non-selective herbicides on wheat pre-harvest impairs the physical and physiological quality and promotes faster deterioration. Vigor is reduced under stress conditions by cold test and accelerated aging. There is no influence on seed sanity.
The use of wheat seeds [Triticum aestivum (L).] of high quality can provide a fast establishment of plants, thus, ensuring the number of plants per area which is the first component of the yield to be set. In the reproductive stage the occurrence of unfavorable environmental factors can affect the seed quality. Temperature and relative humidity, as well as, high levels of rainfall are commonplace in late spring in southern Brazil. Reducing time of exposure of seeds to stress caused by the environment is a viable strategy to ensure the physical, physiological and sanitary quality [
Herbicides can be used in the pre-harvest for weed control, as well as, promote drying of the plant and force the loss of the moisture content of the seed mass, promoting harvest more quickly and efficiently [
The decision on the timing in pre-harvest for herbicide application is crucial to the success of the practice. Often, it is suitable when the plant is physiological maturity and has the lowest seed moisture as possible. In this way, the possibility of herbicide vascular tissue translocation is minimized, and the main route of contamination would be direct contact caused by spraying [
Initially, the experiment was carried out in the field area at Department of Plant Science at the Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil (29˚42'S, 53˚42' at an altitude of 116 m). The sowing (300 viable seeds m2) ocurred on June 23, 2017, using the cultivars BRS Parrudo e TBIO Sinuelo. Mineral fertilization in sowing furrow (400 kg・ha−1 of 05-20-20 NPK) and topdressing (90 kg・ha−1 of urea) was calculated according to the interpretation of the soil analysis [
The treatments were randomized in a factorial plus additional treatment (3 × 4 + 1), totaling 13 treatments. On the first factor, were allocated the three herbicides, the second factor were allocated the four phenological stages of application of herbicides and the additional without application. As for the herbicides: glufosinate-ammonium [Finale®, 350 g active ingredient (a.i.) ha−1], glyphosate (Stinger®, 1440 g a.i. ha−1) e paraquat (Gramoxone®, 400 g a.i. ha−1). As the phenological stages of application of herbicides [
This work was carried out in the Laboratory of Seed Research and Teaching (UFSM). The seeds were dried naturally by exposure to the sun until reaching the optimum moisture for storage (13% - 14%). The seeds were stored in paper packages in a cool and dry environment for a period of two months. The water content of seeds was determined using a laboratory oven at 105˚C ± 3˚C for 24 hours. The 1000-seed mass was determined by measuring the mass of eight plots of 100 seeds [
Germination was evaluated by the first count of the germination test (FCGT) and germination (GER). We used 800 seeds, sown in germiteste moistened paper rolls to 2.5 times the mass of the dry paper and kept in the incubator at 20˚C. The evaluations were conducted at four and eight days after beginning of the test [
It was calculated the speed index (SI) the sowing of 800-seeds in soil substrate. The daily count of the number of emerged seedlings until that number remained constant, being considered the emerged seedlings visible on the surface of the substrate. The emergencein soil (EMERs) was determined by counting the plants emergedin 20 days after sowing.
Were measured the seedling shoot length (SL) and radicle (RL), selecting at random 20 normal seedlings after four days of germination test installation [
-BRS Parrudo- | -TBIO Sinuelo- | |||||||
---|---|---|---|---|---|---|---|---|
HER* | GLU | GLY | PAR | TWA | GLU | GLY | PAR | TWA |
PS | Watercontent (%) | |||||||
Z-83 | 14.3 | 14.6 | 14.2 | 13.6 | 13.9 | 13.9 | 14.0 | 14.3 |
Z-85 | 14.1 | 14.3 | 14.2 | 13.9 | 14.6 | 14.4 | ||
Z-87 | 13.3 | 13.8 | 14.1 | 13.9 | 14.2 | 14.4 | ||
Z-92 | 13.3 | 13.8 | 13.6 | 14.0 | 14.0 | 14.4 | ||
1000-seedmass (g) | ||||||||
Z-83 | 36.0 | 37.4 | 36.6 | 39.0 | 30.0 | 31.8 | 29.6 | 35.8 |
Z-85 | 37.3 | 38.1 | 37.0 | 34.4 | 35.1 | 33.1 | ||
Z-87 | 38.8 | 39.4 | 38.3 | 35.0 | 35.0 | 35.6 | ||
Z-92 | 39.8 | 38.2 | 38.4 | 37.0 | 36.0 | 36.9 |
*Herbicides (HER), phenological stage (PS), glufosinate-ammonium (GLU), glyphosate (GLY), paraquat (PAR), treatment without application (TWA). The dates October 24, October 28, November 01, November 06 and November 14, represents the application of herbicides on Z-83, Z-85, Z-87, Z-92 and harvesting of the TWA, respectively.
constant weight [
These characters were evaluated with the plants emerged in soil, by selecting 20-normal randomly plants with 20 days. Thus, it was determined the shoot lenght (SLs) and root (RLs) and the plant dry mass (PDMs) emerged in soil [
Germination by cold test (CT) was done according to methodology described for germination testing, adapting to the conditions of time and temperature in 5˚C for seven days, respectively [
The indirect measurement of physical integrity was made by electrical conductivity (EC). Four replicates were used of 50-seeds with weight set, deposited in beakers and immersed in 75 mL of distilled and deionized water, taken the incubator at 20˚C, for a period of six hours. After this period, a conductivimeter was then used to measure the electrical conductivity of the solution [
The incidence of pathogens was evaluated by blotter test (BT).The incidence of pathogens was evaluated by blotter spot test (BT). 200 seeds were used, divided into four repetitions and placed in gerbox, seed dispersal on two sheets of paper germiteste sterile and moistened with distilled and autoclaved water in proportion to 2.5 times your weight [
For the analysis, a completely randomized design was used and the tested cultivars were evaluated separately. The data were verified and met the mathematical model assumptions for errors normality [Shapiro-Wilk (P ≤ 0.05)] and homogeneity of the variances [Bartlett (P ≤ 0.05)]. A subsequent analysis of variance [F-test (P ≤ 0.05)] was conducted, by comparing the degrees of freedom of the treatments versus the treatment without application [Scheffé (P ≤ 0.05)] and the complementary grouping test [Scott-Knott (P ≤ 0.05)]. Software Action® (Estatcamp, São Carlos, SP, Brazil), Genes® [
About the interactions, it was verified that most of them were significant, as well as, contrasts with results favorable to the treatment without application (TWA) (
S.V.1 | D.F. | FCGT | GER | SL | RL | SDM | SI | EMERs | SLs | RLs | PDMs | CT | AA | EC |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Treatments | 12 | 503.6** | 321.3** | 1.16** | 8.14** | 18.9** | 3.48** | 343.4** | 4.24** | 5.03** | 156.9** | 327.8** | 435.4** | 54.2** |
Fatorial | 11 | 517.1** | 340.8** | 1.16** | 8.71** | 19.8** | 3.64** | 359.2** | 4.36** | 4.01** | 165.3** | 352.5** | 473.9** | 54.6** |
Contrast | 1 | 354.8** | 106.3** | 1.08ns | 1.84** | 8.6ns | 1.68* | 170.3* | 2.96ns | 16.30** | 65.1ns | 55.9ns | 12.0ns | 49.0** |
Error | 39 | 7.8 | 5.7 | 0.07 | 0.17 | 4.6 | 0.26 | 31.8 | 0.94 | 1.28 | 26.1 | 22.1 | 9.1 | 0.8 |
A (Herb.) | 3 | 1076.6 | 658.1 | 1.74 | 17.33 | 9.2 | 3.41 | 900.8 | 1.87 | 3.28 | 135.9 | 407.3 | 702.4 | 142.2 |
D (Phen.St.) | 2 | 746.8 | 404.7 | 0.64 | 13.09 | 8.5 | 3.71 | 465.2 | 0.83 | 6.76 | 386.7 | 718.7 | 721.2 | 49.7 |
A x D | 6 | 160.9 | 160.8 | 1.06 | 2.96 | 28.8 | 3.75 | 53.1 | 6.79 | 3.46 | 106.2 | 203.1 | 277.2 | 12.5 |
Average | 77.2 | 84.6 | 3.2 | 5.5 | 30.2 | 1.80 | 75.7 | 12.2 | 12.9 | 58.5 | 90.1 | 74.5 | 12.7 | |
CV (%) | 4.5 | 3.5 | 8.2 | 7.6 | 7.2 | 6.64 | 9.2 | 8.0 | 8.8 | 8.7 | 6.4 | 5.0 | 4.3 | |
-Contrasts- | ||||||||||||||
Treatments | 9.80** | 5.36** | 0.45ns | 0.70** | 1.53ns | 0.67** | 6.79** | 0.89ns | 2.10** | 4.20ns | 3.89ns | 1.80ns | −3.64** | |
glufosinate | 3.96** | 1.37ns | 0.30* | −0.27ns | 2.34ns | 0.60ns | 4.65ns | 0.67ns | 2.75** | 4.30ns | −2.34ns | −1.61ns | −2.04** | |
glyphosate | 8.12** | 3.70** | 0.68** | 0.89** | 0.93ns | 0.23ns | 2.7ns | 0.87ns | 2.10** | −0.76ns | 3.05ns | −2.50ns | −5.53** | |
paraquat | 17.31** | 11.01** | 0.38** | 1.50** | 1.32ns | 1.18** | 12.92** | 1.13ns | 1.45ns | 9.06** | 10.97** | 9.54** | −3.36** | |
Z-83 | 22.38** | 15.46** | 0.97** | 2.21** | 0.65ns | 1.45** | 18.55** | 1.18ns | 2.77** | 7.75ns | 11.36** | 13.11** | −6.34** | |
Z-85 | 10.95** | 4.07** | 0.37** | 1.14** | 2.02ns | 0.36ns | 5.82ns | 0.59ns | 2.23** | 0.96ns | 2.14ns | −1.35ns | −6.89** | |
Z-87 | 5.70** | 4.29** | 0.42** | −0.26ns | 2.50ns | 0.31ns | 5.10ns | 1.28ns | 1.58ns | 1.71ns | 4.68ns | −0.72ns | −0.52ns | |
Z-92 | 0.17ns | −2.36ns | 0.05ns | −0.26ns | 0.95ns | 0.56ns | −2.32ns | 0.52ns | 1.81ns | 6.36ns | −2.61ns | −3.79ns | −0.81ns |
1Source of variation (S.V.), degree of freedom (D.F.), coefficient of variation (CV%). Characters: first count of germination test (FCGT) and germination (GER), seedling shoot length (SL) and radicle (RL), seedling dry mass (SDM), speed index (SI), emergence in soil (EMERs), plant shoot length (SLs) and root (RLs) emerged in soil, dry mass of plants emerged in soil (PDMs), cold test (CT), accelerated aging test (AA), electrical conductivity (EC); not significant, 5% and 1% statistical difference by F-test (ns, * and **, respectively). Estimates of the contrasts [Scheffé (P ≤ 0.05)] with positive numbers are favorable to treatment without application or negative to the treatments with herbicides.
S.V.1 | D.F. | FCGT | GER | SL | RL | SDM | SI | EMERs | SLs | RLs | PDMs | CT | AA | EC |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Treatments | 12 | 1105.7** | 791.0** | 0.95** | 9.34** | 14.8** | 8.63** | 537.1** | 6.65** | 15.91** | 130.1** | 890.8** | 687.3** | 66.5** |
Fatorial | 11 | 1078.6** | 800.7** | 0.88** | 9.45** | 15.9** | 9.07** | 576.3** | 7.24** | 16.66** | 141.8** | 875.0** | 680.7** | 68.2** |
Contrast | 1 | 1403.7** | 684.1** | 1.75** | 8.15** | 2.9ns | 3.79** | 105.9** | 0.15ns | 7.66ns | 1.4ns | 1063.8** | 760.0** | 48.8** |
Error | 39 | 5.9 | 8.7 | 0.10 | 0.20 | 3.6 | 0.23 | 4.5 | 2.00 | 2.27 | 22.8 | 27.4 | 14.5 | 0.9 |
A (Herb.) | 3 | 2624.1 | 1879.9 | 2.15 | 12.73 | 46.7 | 14.03 | 1105.4 | 23.87 | 22.72 | 468.7 | 2002.1 | 1027.2 | 213.5 |
D (Phen.St.) | 2 | 1311.9 | 1098.4 | 0.85 | 28.17 | 4.4 | 15.86 | 843.6 | 0.26 | 39.74 | 23.0 | 1292.8 | 1459.3 | 36.9 |
A x D | 6 | 228.1 | 162.0 | 0.26 | 1.57 | 4.4 | 4.34 | 222.6 | 1.26 | 5.95 | 17.9 | 172.2 | 247.9 | 5.9 |
Average | 66.6 | 74.4 | 2.9 | 4.4 | 27.2 | 1.37 | 62.3 | 11.1 | 11.0 | 48.5 | 78.1 | 51.2 | 12.1 | |
CV (%) | 4.4 | 4.9 | 11.1 | 10.3 | 7.0 | 7.34 | 4.1 | 12.7 | 13.5 | 9.8 | 8.2 | 8.6 | 4.8 | |
-Contrasts- | ||||||||||||||
Treatments | 19.49** | 13.61** | 0.68** | 1.48** | −0.89ns | 1.01** | 5.35** | 0.20ns | −1.44ns | 0.61ns | 16.97** | 14.34** | −3.63** | |
glufosinate | 11.27** | 5.16** | 0.51** | −0.04ns | −1.31ns | 0.44ns | 0.74ns | 0.10ns | −3.26** | 0.76ns | 7.56** | 7.89** | −2.20** | |
glyphosate | 18.00** | 13.94** | 0.94** | 2.22** | −0.30ns | 0.43ns | 1.59ns | 0.16ns | −0.54ns | 1.73ns | 17.88** | 9.83** | −5.22** | |
paraquat | 29.20** | 21.72** | 0.60** | 2.28** | −1.05ns | 2.16** | 13.72** | 0.34ns | −0.51ns | −0.65ns | 25.47** | 25.31** | −3.47** | |
Z-83 | 37.05** | 29.45** | 1.26** | 2.48** | −0.34ns | 2.28** | 16.27** | 1.82ns | −0.08ns | 7.10ns | 32.49** | 25.92** | −6.75** | |
Z-85 | 25.64** | 17.33** | 0.74** | 2.26** | 0.10ns | 1.49** | 9.50** | 0.90ns | −0.43ns | 4.57ns | 22.47** | 16.33** | −7.77** | |
Z-87 | 11.47** | 6.45** | 0.32ns | 0.65ns | 0.48ns | 0.40ns | 1.47ns | −1.25ns | −2.74** | −6.19ns | 8.54** | 11.23** | 0.33ns | |
Z-92 | 3.82ns | 1.20ns | 0.42ns | 0.54ns | −3.80ns | −0.12ns | −5.82ns | −0.65ns | −2.49** | −3.00ns | 4.38ns | 3.89ns | −0.35ns |
1Source of variation (S.V.), degree of freedom (D.F.), coefficient of variation (CV%). Characters: first count of germination test (FCGT) and germination (GER), seedling shoot length (SL) and radicle (RL), seedling dry mass (SDM), speed index (SI), emergence in soil (EMERs), plant shoot length (SLs) and root (RLs) emerged in soil, dry mass of plants emerged in soil (PDMs), cold test (CT), accelerated aging test (AA), electrical conductivity (EC); not significant, 5% and 1% statistical difference by F-test (ns, * and **, respectively). Estimates of the contrasts [Scheffé (P ≤ 0.05)] with positive numbers are favorable to treatment without application or negative to the treatments with herbicides.
The first count of the germination test (FCGT) was 18% higher than for the treatment without application (TWA), differed statistically of the treatments with herbicides, except for the Z-92 stage (
The seedling shoot length (SL, 3.2 cm) and dry mass (SDM, 30.1 mg) of herbicide treatments did not differ statistically from the TWA (3.7 cm and 31.6 mg,
-BRS Parrudo- | -TBIO Sinuelo- | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
HER1 | GLU | GLY | PAR | TWA | GLU | GLY | PAR | TWA | |||||||||||||
PS | First count of germination test (FCGT, % normal seedlings) | ||||||||||||||||||||
Z-83 | 81.3 | bA* | 56.0 | dB | 33.0 | dC | 90.0(1) | 64.7 | cA | 37.5 | cB | 10.5 | dC | 92.0(1) | |||||||
Z-85 | 86.0 | bA | 78.7 | cB | 61.3 | cC | 67.3 | cA | 66.0 | bA | 32.0 | cB | |||||||||
Z-87 | 84.0 | bA | 87.0 | bA | 78.5 | bB | 86.0 | bA | 80.0 | aB | 67.0 | bC | |||||||||
Z-92 | 90.0 | aA | 92.7 | aA | 86.0 | aB | 91.0 | aA | 84.5 | aB | 88.0 | aA | |||||||||
Germination test (GER, % normal seedlings) | |||||||||||||||||||||
Z-83 | 89.3 | bA | 73.3 | cB | 46.0 | cC | 91.3(1) | 74.7 | cA | 47.0 | cB | 24.5 | dC | 92.0(1) | |||||||
Z-85 | 89.3 | bA | 87.5 | bA | 84.0 | bB | 81.3 | bA | 72.5 | bB | 52.0 | cC | |||||||||
Z-87 | 86.5 | bA | 88.5 | bA | 85.0 | bA | 93.3 | aA | 86.0 | aB | 72.5 | bC | |||||||||
Z-92 | 94.0 | aA | 96.0 | aA | 89.5 | aB | 93.0 | aA | 87.0 | aB | 91.5 | aA | |||||||||
Seedling shoot length (SL, cm) | |||||||||||||||||||||
Z-83 | 3.3 | bA | 2.4 | cB | 2.4 | cB | 3.7ns | 2.5 | cA | 2.0 | bB | 2.5 | bA | 3.5(1) | |||||||
Z-85 | 3.8 | aA | 3.2 | aB | 2.9 | bB | 3.2 | bA | 2.6 | aB | 2.7 | bB | |||||||||
Z-87 | 3.2 | bB | 2.8 | bC | 3.8 | aA | 3.7 | aA | 3.0 | aB | 3.1 | aB | |||||||||
Z-92 | 3.2 | bC | 3.6 | aB | 4.1 | aA | 3.0 | bB | 2.9 | aB | 3.6 | aA | |||||||||
Seedling radicle length (RL, cm) | |||||||||||||||||||||
Z-83 | 6.0 | aA | 3.0 | dB | 2.9 | cB | 6.2(1) | 4.9 | cA | 2.0 | bC | 3.1 | bB | 5.8(1) | |||||||
Z-85 | 6.4 | aA | 5.1 | cB | 3.6 | bC | 5.7 | bA | 2.4 | bB | 2.5 | bB | |||||||||
Z-87 | 6.9 | aA | 6.2 | bB | 6.2 | aB | 6.6 | aA | 4.8 | aB | 4.0 | aC | |||||||||
Z-92 | 6.5 | aA | 6.9 | aA | 5.9 | aB | 6.2 | aA | 5.2 | aB | 4.5 | aC | |||||||||
Seedling dry mass (SDM, mg) | |||||||||||||||||||||
Z-83 | 31.4 | aA | 31.3 | aA | 30.3 | bA | 31.6ns | 26.6 | bA | 26.3 | aA | 27.4 | bA | 26.4ns | |||||||
Z-85 | 26.7 | bB | 28.4 | aB | 33.7 | aA | 26.9 | bA | 27.0 | aA | 25.1 | bA | |||||||||
Z-87 | 27.3 | bB | 32.6 | aA | 27.5 | bB | 26.6 | bA | 25.2 | aA | 26.0 | bA | |||||||||
Z-92 | 31.8 | aA | 30.5 | aA | 29.7 | bA | 30.8 | aA | 28.5 | aA | 31.4 | aA | |||||||||
1Herbicides (HER), phenological stage (PS), glufosinate-ammonium (GLU), glyphosate (GLY), paraquat (PAR), treatment without application (TWA). *Lowercase letters (PS within each HER) and uppercase (HER withim each PS) distinct differ[Scott-Knott (P ≤ 0.05)]. Results of the contrast [Scheffé (P ≤ 0.05)] are favorable to treatment without application(1), treatment with herbicides(2) and not significant(ns).
respectively). In two early stages (Z-83 and Z-85) the applications of glufosinate-ammonium originated seedlings of largest SL; in contrast, to the last two application stages (Z-87 and Z-92), paraquat applications have higher seedling. The Z-92 stage did not statistically differ from TWA in SL. As for SDM, the applications in the Z-83 and Z-92 stages are independent of the herbicide used; the treatment with paraquat applied to Z-85 resulted in heavier seedlings, as well as, glyphosate in the Z-87 stage. Seedling radicle length (RL) was also influenced by
-BRS Parrudo- | -TBIO Sinuelo- | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
HER¹ | GLU | GLY | PAR | TWA | GLU | GLY | PAR | TWA | ||||||
PS | Speed index (SI, % normal seedlings) | |||||||||||||
Z-83 | 1.8 | bA* | 1.6 | bA | 0.9 | cB | 2.1(1) | 1.3 | bA | 1.3 | bA | 0.3 | dB | 1.726(1) |
Z-85 | 1.3 | cB | 2.1 | aA | 1.5 | bB | 1.4 | bA | 1.4 | bA | 0.6 | cB | ||
Z-87 | 2.1 | aA | 2.1 | aA | 1.5 | bB | 1.6 | aB | 1.9 | aA | 1.1 | bC | ||
Z-92 | 2.1 | aA | 2.0 | aA | 2.2 | aA | 1.9 | aA | 1.5 | bB | 1.9 | aA | ||
Emergence in soil (EMERs, % normal seedlings) | ||||||||||||||
Z-83 | 55.5 | bB | 70.0 | bA | 44.7 | cB | 85.5(1) | 60.7 | cA | 60.0 | cA | 13.0 | dB | 70.6(1) |
Z-85 | 81.5 | aA | 84.5 | aA | 64.7 | bB | 61.3 | cA | 62.0 | cA | 40.7 | cB | ||
Z-87 | 83.0 | aA | 84.0 | aA | 67.5 | bB | 75.0 | bA | 70.7 | bA | 58.7 | bB | ||
Z-92 | 91.5 | aA | 86.5 | aA | 86.0 | aA | 79.5 | aA | 78.7 | aA | 80.0 | aA | ||
Plant shoot length emerged in soil (SLs, cm) | ||||||||||||||
Z-83 | 13.5 | aA | 10.7 | bB | 11.3 | aB | 13.0ns | 10.6 | aA | 9.3 | bA | 8.8 | bA | 11.3ns |
Z-85 | 13.1 | aA | 12.4 | aA | 11.8 | aA | 10.3 | aA | 10.5 | bA | 10.5 | bA | ||
Z-87 | 9.9 | bB | 13.0 | aA | 12.3 | aA | 12.4 | aA | 12.8 | aA | 12.6 | aA | ||
Z-92 | 12.9 | aA | 12.5 | aA | 12.2 | aA | 11.7 | aA | 12.2 | aA | 12.1 | aA | ||
Plant root length emerged in soil (RLs, cm) | ||||||||||||||
Z-83 | 12.5 | aA | 11.5 | bA | 12.4 | aA | 14.9(1) | 13.1 | aA | 8.1 | bB | 8.2 | bB | 9.7ns |
Z-85 | 12.4 | aA | 12.6 | bA | 13.1 | aA | 12.2 | aA | 8.5 | bB | 9.8 | bB | ||
Z-87 | 11.6 | aB | 14.5 | aA | 13.8 | aA | 14.3 | aA | 11.9 | aB | 11.2 | aB | ||
Z-92 | 12.2 | aB | 12.7 | bB | 14.5 | aA | 12.3 | aA | 12.5 | aA | 11.8 | aA | ||
Plant dry mass emerged in soil (PDMs, mg) | ||||||||||||||
Z-83 | 52.9 | bB | 59.7 | bA | 51.4 | aB | 62.4ns | 44.1 | bA | 39.7 | cA | 42.2 | bA | 49.1ns |
Z-85 | 63.9 | aA | 68.8 | aA | 51.7 | aB | 44.6 | bA | 44.0 | cA | 45.0 | bA | ||
Z-87 | 56.5 | bB | 70.4 | aA | 55.2 | aB | 52.1 | aA | 56.3 | aA | 57.4 | aA | ||
Z-92 | 59.2 | aA | 53.8 | bA | 55.1 | aA | 52.5 | aA | 49.4 | bA | 54.4 | aA |
1Herbicides (HER), phenological stage (PS), glufosinate-ammonium (GLU), glyphosate (GLY), paraquat (PAR), treatment without application (TWA). *Lowercase letters (PS within each HER) and uppercase (HER withim each PS) distinct differ [Scott-Knott (P ≤ 0.05)]. Results of the contrast [Scheffé (P ≤ 0.05)] are favorable to treatment without application(1), treatment with herbicides(2) and not significant (ns).
herbicides, differing statistically from TWA, except for the Z-87 and Z-92 stages. In general, the herbicide glufosinate-ammonium independently of the phenological stage of application originated seedlings with higher roots length.
The TWA presented 16% higher germination speed index (SI) than herbicide treatments, differing statistically for the herbicide paraquat, as well as, the Z-83 stage (
-BRS Parrudo- | -TBIO Sinuelo- | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
HER¹ | GLU | GLY | PAR | TWA | GLU | GLY | PAR | TWA | ||||||
PS | Cold test (CT, % normal seedlings) | |||||||||||||
Z-83 | 95.5 | aA* | 86.7 | bB | 58.0 | cC | 93.5ns | 80.5 | bA | 48.0 | cB | 34.0 | dC | 96.0(1) |
Z-85 | 98.0 | aA | 93.5 | aB | 84.7 | bC | 88.0 | bA | 72.0 | bB | 51.0 | cC | ||
Z-87 | 94.5 | aA | 93.0 | aA | 84.5 | bB | 97.0 | aA | 91.5 | aA | 77.0 | bB | ||
Z-92 | 96.5 | aA | 95.5 | aA | 97.5 | aA | 94.5 | aA | 92.5 | aA | 94.0 | aA | ||
Accelerate aging test (AA, % normal seedlings) | ||||||||||||||
Z-83 | 71.0 | bA | 73.3 | ba | 25.5 | cB | 78.0ns | 54.0 | aA | 35.3 | cB | 6.5 | dC | 72.5(1) |
Z-85 | 86.7 | aA | 86.0 | aA | 64.7 | bB | 63.3 | aA | 51.5 | bB | 22.0 | cC | ||
Z-87 | 82.5 | aA | 84.7 | aA | 68.7 | bB | 59.0 | aA | 67.3 | aA | 35.3 | bB | ||
Z-92 | 79.3 | aB | 80.7 | aB | 88.7 | aA | 62.7 | aA | 70.5 | aA | 66.0 | aA | ||
Electrical conductivitytest (EC, µS・cm−1・g−1) | ||||||||||||||
Z-83 | 12.0 | bC | 22.5 | aA | 14.7 | bB | 8.9(2) | 13.8 | aB | 18.8 | bA | 15.2 | bB | 8.2(2) |
Z-85 | 14.4 | aB | 18.8 | bA | 17.5 | aA | 13.3 | aC | 21.0 | aA | 17.6 | aB | ||
Z-87 | 8.3 | cB | 10.2 | cA | 9.9 | cA | 7.6 | bA | 8.7 | cA | 7.4 | cA | ||
Z-92 | 9.8 | cA | 10.5 | cA | 8.9 | cA | 8.0 | bA | 9.1 | cA | 8.7 | cA |
1Herbicides (HER), phenological stage (PS), glufosinate-ammonium (GLU), glyphosate (GLY), paraquat (PAR), treatment without application (TWA). *Lowercase letters (PS within each HER) and uppercase (HER withim each PS) distinct differ [Scott-Knott (P ≤ 0.05)]. Results of the contrast [Scheffé (P ≤ 0.05)] are favorable to treatment without application(1), treatment with herbicides(2) and not significant(ns).
and did not differ statistically for the Z-83, Z-87 and Z-92 stages and also for the herbicides glufosinate-ammonium and glyphosate. However, the results of plant shoot lenght (SLs), dry mass (PDMs) and root lenght (RLs) emerged in soil, coincided with the characters measured in laboratory conditions, i.e., they did not differ statistically for the first two and there were 16% (TWA) for RLs.
To the cold test (CT), TWA did not differ statistically from herbicide treatments, except for the Z-83 stage and the herbicide paraquat; for these conditions the TWA obtained increases of 16% and 15%, respectively (
For the blotter test (BT) there was no statistical difference between the contrasts, but the herbicide paraquat reduced the incidence of fungi by 11% when compared to the TWA (
Herbicides | GLU1 | GLY | PAR | TWA | GLU | GLY | PAR | TWA |
---|---|---|---|---|---|---|---|---|
Pathogens | -BRS Parrudo- | -TBIO Sinuelo- | ||||||
FUS | 53.9 aA* | 52.0 aA | 54.4 aA | 53.3 aA | 53.9 aB | 58.94 aA | 63.2 cA | 61.5 aA |
ALT | 16.8 cA | 19.4 cA | 16.7 cA | 13.4 cB | 27.8 bA | 21.8 bB | 19.8 bB | 18.1 bB |
ASP | 0.0 dA | 0.0 dA | 0.0 dA | 0.3 dA | 0.0 dA | 0.0 dA | 0.0 cA | 0.4 cA |
CLA | 25.9 bA | 24.3 bA | 28.5 bA | 28.5 bA | 17.5 cA | 16.3 cA | 16.6 bA | 19.4 bA |
CUR | 2.8 dA | 3.3 dA | 1.5 dA | 1.5 dA | 2.5 dA | 2.2 dA | 0.8 cA | 0.4 cA |
BIP | 0.0 dA | 0.3 dA | 0.0 dA | 0.0 dA | 0.4 dA | 0.8 dA | 0.0 cA | 0.0 cA |
PHO | 2.1 dA | 0.7 dA | 2.7 dA | 2.7 dA | 0.0 dA | 0.7 dA | 0.9 cA | 1.7 cA |
S.V. | D.F. | Meansquares | Meansquares | |||||
Treatments | 3 | 1.93ns | 0.18ns | |||||
Pathogens | 6 | 6375.9* | 892.7* | |||||
Trat x Path. | 18 | 8.42ns | 2.98ns | |||||
Error | 84 | 7.25 | 8.49 | |||||
Average | 18.58 | 14.51 | ||||||
CV (%) | 14.50 | 20.08 | ||||||
-Contrasts- | ||||||||
Treatments | 0.22ns | −0.06ns | ||||||
glufosinate | 0.23ns | −0.08ns | ||||||
glyphosate | −0.07ns | −0.10ns | ||||||
paraquat | 0.51ns | 0.08ns |
1Herbicides: glufosinate-ammonium (GLU), glyphosate (GLY), paraquat (PAR), treatment without application (TWA). Source of variation (S.V.), degree of freedom (D.F.), coefficient of variation (CV%). Pathogens: Fusarium sp. (FUS), Alternariaalternata (ALT), Aspergillus sp. (ASP), Cladosporiumcladosporioides (CLA), Curvularia luneta (CUR), Bipolarissorokiniana (BIP), Phoma sp. (PHO). *Lowercase letters (pathogens within each herbicide) and uppercase (herbicides withim each pathogen) distinct differ [Scott-Knott (P ≤ 0.05)] and results of contrast [Scheffé (P ≤ 0.05)] not significant(ns).
The FCGT was 42% higher for the TWA than the others (
In absolute numbers, there was emphasis on the Z-92 stage (79%) for the EMERs in relation to TWA (70%), however, no differ statistically; in none of the treatments tested was reached the minimum requirement for use as seeds. For the SLs, RLs and PDMs, there was no statistical difference, except for the herbicide glufosinate-ammonium, as well as, Z-87 and Z-92, which had 33%, 28% and 25% higher plant roots than the control.
Germination in CT and AA was higher in TWA treatment (25% and 46%, respectively) compared to herbicides treatment (
The results from the FCGT and GER tests showed the same relation in their means, with a reduction of the physiological potential with applications previous to the Z-87 stage, as well as, the use of glyphosate and paraquat herbicides. These two herbicides affect wheat germination, with a more pronounced effect for the second that is 7% more harmful than glyphosate [
As for the application stage, [
The SL and RL are decreased by the application of herbicides, regardless of the phenological stage of application, and there is a tendency for the maintenance of growth expression when using glufosinate-ammonium applied in Z-92. There is a negative influence among herbicides compared to TWA, because seedlings with shoot and smaller rootlets are obtained [
There were reductions in the IS and EMERs inherent in the use of herbicides; the results followed the trend of tests expressing initial vigor and final germination (FCGT and GER). Smaller reductions were observed with use of glufosinate-ammonium and applications on Z-92 stage. In sand, seed emergence from plants desiccated with gliphosate at the Z-87 stage, when allocated up to 4 cm deep, did not differ statistically from the non-desiccated control [
For growth characters measured in soil conditions (SLs, RLs and PDMs) there were no interferences from the use of herbicides. However, when comparing cultivars, BRS Parrudo obtained larger SLs in the TWA treatment, and TBIO Sinuelo in the treatments with glufosinate-ammonium applied in the Z-87 and Z-92 stages. The size of the coleoptile can be affected, generating smaller seedlings, however, this is an inconsistent evaluation to express the vigor. Plants with more than one week are necessary for shoot and root evaluation [
The tests that express the physiological potential under adverse stress conditions (CT and AA) differed in terms of plant cultivars. For BRS Sinuelo, both tests did not differ from TWA and TBIO Sinuelo treatment with herbicides have damaged the germination. Using the cultivar Quartzo, [
Higher seed deterioration was evidenced by high EC measured in herbicide treatments, regardless of the active ingredient in the first two application stages (Z-83 and Z-85). These results corroborate [
The fungal incidence measured by BT was not affected by herbicide treatments, with presence of pathogens in any of the conduction conditions of the experiment. The pathogen F. graminearum (teleomorph Giberellazeae), causes giberela in cereals, is widely disseminated in the agricultural field areas, and was present in practically all the samples evaluated in our experiment. High levels of rainfall during the harvest period contribute to the infection of seeds [
The quality of seeds from plants where pre-harvest herbicide applications were strongly influenced by the phenological stage and the proximity of phenological maturation at the time of application than by the dose of herbicide or cultivar [
The application of non-selective herbicides on wheat pre-harvest impairs the physical and physiological quality and promotes faster deterioration. Vigor is reduced under stress conditions by cold test and accelerated aging. There is no influence on seed sanity.
In general, applications in phenological stages prior to Z-87 stage, especially with the herbicide paraquat should be avoided.
The authors would like to thank the Higher-Level Personnel Improvement Coordination (Capes-Brazil) for the scholarship provided, The National Council for Scientific and Technological Development (CNPq).
Fipke, G.M., Martin, T.N., Nunes, U.R., Deak, E.A., Stecca, J.D.L., Winck, J.E.M., Grando, L.F.T. and Rossato, A.C. (2018) Application of Non- Selective Herbicides in the Pre-Harvest of Wheat Damages Seed Quality. American Journal of Plant Sciences, 9, 107-123. https://doi.org/10.4236/ajps.2018.91010