Treatment of soybean seeds with mechanical damage: effects on their physiological potential

Oliveira, Gustavo Roberto Fonseca de; Cicero, Silvio Moure; Krzyzanowski, Francisco Carlos; Gomes-Junior, Francisco Guilhien; Batista, Thiago Barbosa; França-Neto, José de Barros

doi:10.1590/2317-1545v43247404

Abstract:

Mechanical damage is a serious problem for the physiological potential of soybean seeds, especially when combined with chemical treatment. The aim of this study was to investigate the effects of chemical treatment on the physiological potential of soybean seeds with increasing levels of mechanical damage. Soybean seeds (cv. M6410 IPRO) of two lots with differences in vigor were subjected to five levels of mechanical damage (zero, one, two, three, and four impacts) brought about in a controlled manner. After characterization of the effect of the impacts on seed physical integrity (X-ray, X-ray microtomography, tetrazolium, and sodium hypochlorite), the seeds were subjected to four combinations of chemical treatment with fungicides (carbendazim and thiram), insecticides (imidacloprid and thiodicarb), micronutrients (cobalt and molybdenum), polymer (Peridiam®), and drying powder (Talkum Gloss®). Seed germination and vigor were evaluated sixty days after chemical treatment. A progressive increase in mechanical damage, especially that which causes cracks in the seed coat, reduces the physiological potential of soybean seeds and increases their sensitivity to the phytotoxic effect of the chemical treatment. The physical integrity of the seed coat is crucial for the success of technologies used for chemical seed treatment.

Index terms:
Glycine max; mechanical damage in seeds; phytotoxicity of chemical treatment; germination; vigor; seed and seedling image analysis

[1] *Corresponding author
E-mail: grfonseca.agro@gmail.com

ST	Sample	F¹ 1 Fungicides (formulation containing the mixture of carbendazim and thiram; 2 mL.kg-1).	I² 2 Insecticides (formulation containing the mixture of imidacloprid + thiodicarb; 5 mL.kg-1).	M³ 3 Micronutrients (CoMo®: formulation containing a mixture of cobalt and molybdenum; 1.2 mL.kg-1).	P⁴ 4 Polymer (Peridiam®; 2 mL.kg-1).	Total	Total	DP⁵ 5 Drying powder (Talkum Gloss®; 3.5 g.kg-1).
ST	g^ Weight (g) of seeds under treatment.	----------------- mL ----------------				mL.100 kg^-1		g
T0^* * T0: untreated seeds; T1: micronutrients; T2: fungicides + micronutrients; T3: insecticides + micronutrients; T4: fungicides + insecticides + micronutrients.	500	-	-	-	-	0.0	0.0	-
T1	500	-	-	0.6	1.0	1.6	320	1.8
T2	500	1.0	-	0.6	1.0	2.6	520	1.8
T3	500	-	2.5	0.6	1.0	4.1	820	1.8
T4	500	1.0	2.5	0.6	1.0	5.1	1020	1.8

NI	Lot 1						Lot 2
	Tetrazolium %					SC (%)	Tetrazolium %					SC (%)
	MD	MDT	ID	VB	VG¹ 1 Vigor classification: very high: ≥ 90%; high: 85% to 89%; medium: 75% to 84%; low: ≤ 74%.	SC (%)	MD	MDT	ID	VB	VG¹ 1 Vigor classification: very high: ≥ 90%; high: 85% to 89%; medium: 75% to 84%; low: ≤ 74%.	SC (%)
0	2	2	2	94	87	8	3	0	1	96	88	7
1	6	1	3	90	80	11	14	0	2	84	75	17
2	12	0	6	82	73	13	16	3	1	80	74	18
3	11	2	4	83	72	12	25	1	1	73	66	21
4	14	1	6	79	71	14	26	1	0	73	72	27

Score¹ 1 Scores 1, 2, and 3 correspond to mechanical damage not observed, not severe, and severe, respectively; the first number of each notation corresponds to the embryonic axis, and the second to the cotyledons.	Number of impacts					Total	Observation (%)² 2 Percentage of normal seedlings (NS), abnormal seedlings (AS), and dead seeds (DS) after the germination test (five days).
	0	1	2	3	4	Total	NS	AS	DS
1.1^L1 L1, L2: Seed lots.	199	191	190	188	186	954	76%	14%	10%
1.2	-	2	2	2	2	8	25%	37.5%	37.5%
1.3	-	-	1	3	3	7	-	2	5
2.1	-	-	-	-	-	-	-	-	-
2.2	-	-	-		-	-	-	-	-
2.3	-	-	-	-	-	-	-	-	-
3.1	-	4	5	6	8	23	-	65%	35%
3.2	1	1	-	-	-	2	-	-	100%
3.3	-	2	2	1	1	6	-	-	100%
T^* * Total number of seeds in which mechanical damage was observed in the X-ray images. L1	1	9	10	12	14	46	4%	43%	53%
1.1^L2 L1, L2: Seed lots.	198	184	176	165	166	889	79%	13%	8%
1.2	1	2	6	5	2	16	37.5%	12.5%	50%
1.3	-	2	1	2	10	15	-	53%	47%
2.1	-	-	-	-	-	-	-	-	-
2.2	-	-	-	-	-	-	-	-	-
2.3	-	-	-	-	-	-	-	-	-
3.1	1	9	10	21	16	56	-	54%	46%
3.2	-	-	3	5	3	11	-	45%	55%
3.3	-	3	4	2	3	13	-	8%	92%
T^* * Total number of seeds in which mechanical damage was observed in the X-ray images. L2	2	16	24	35	34	111	5%	41%	54%

ST	Number of impacts					Number of impacts
ST	0	1	2	3	4	0	1	2	3	4
	First germination count (%)					Total germination (%)
T0	91 Aa^* *Mean values followed by different uppercase letters in each row within each test and by different lowercase letters in each column within each test differ from each other by the Scott-Knott test at the level of 5% probability.	85 Aa	88 Aa	85 Aa	76 Ba	93 Aa	88 Aa	90 Aa	88 Aa	80 Ba
T1	93 Aa	90 Aa	70 Cb	76 Bb	81 Ba	94 Aa	91 Aa	74 Cc	79 Bb	83 Ba
T2	88 Aa	73 Bb	76 Bb	83 Aa	78 Ba	91 Aa	78 Bb	75 Bc	85 Aa	79 Ba
T3	90 Aa	78 Bb	78 Bb	77 Bb	68 Cb	92 Aa	83 Bb	81 Bb	80 Bb	71 Cb
T4	76 Ab	80 Ab	75 Ab	74 Ab	79 Aa	80 Ab	84 Bb	80 Ab	78 Ab	84 Aa
C.V. (%)	6.5					5.6
	Accelerated aging (%)					Moisture content after AA (%)
T0	88 Aa	85 Aa	82 Aa	70 Ba	82 Aa	26.1	25.8	28.2	27.5	24.3
T1	77 Ab	72 Ab	73 Aa	56 Bb	48 Bd	27.5	28.6	26.5	26.6	27.5
T2	77 Ab	74 Ab	73 Aa	66 Aa	69 Ab	25.6	29.1	26.2	28.7	26.1
T3	72 Ac	75 Ab	60 Bb	66 Ba	61 Bc	31.3	27.8	26.3	26.7	27.8
T4	64 Ac	67 Ab	54 Bb	53 Bb	57 Bc	25.3	27.9	27.2	28.4	24.8
C.V. (%)	10.7					5.6
	Vigor index					Growth index
T0	652 Aa	606 Aa	553 Aa	584 Aa	548 Aa	610 Aa	543 Aa	490 Aa	519 Aa	500 Aa
T1	603 Aa	595 Aa	462 Bb	519 Ba	519 Ba	541 Aa	545 Aa	396 Bb	445 Bb	446 Ba
T2	475 Ab	470 Ab	472 Ab	486 Aa	566 Aa	408 Bb	405 Bb	397 Bb	416 Bb	515 Aa
T3	472 Ab	392 Ac	416 Ab	375 Ab	321 Ab	394 Ab	304 Bc	334 Ab	287 Bc	249 Bb
T4	298 Ac	337 Ac	289 Ac	352 Ab	269 Ab	209 Ac	268 Ac	218 Ac	275 Ac	200 Ab
C.V. (%)	13.6					15.5
	Root length (cm)					Seedling length (cm)
T0	5.7 Aa	5.0 Aa	4.5 Aa	4.8 Aa	4.7 Ba	8.8 Aa	8.0 Aa	7.2 Aa	7.7 Aa	7.2 Aa
T1	5.0 Aa	5.1 Aa	3.7 Bb	4.0 Bb	3.9 Ba	8.1 Aa	7.8 Aa	5.8 Bb	6.7 Ba	6.6 Ba
T2	3.7 Ab	3.7 Ab	3.6 Ab	3.8 Ab	4.5 Aa	6.2 Ab	6.2 Ab	6.0 Ab	6.2 Aa	7.5 Aa
T3	3.6 Ab	2.7 Bc	3.0 Ac	2.6 Bc	2.2 Bb	6.1 Ab	4.8 Bc	5.1 Bb	4.6 Bb	3.8 Bb
T4	1.8 Ac	2.4 Ac	1.9 Ad	2.5 Ac	1.7 Ab	3.5 Ac	4.2 Ac	3.4 Ac	4.4 Ab	3.1 Ab
C.V. (%)	16.0					15.7

ST	Number of impacts					Number of impacts
ST	0	1	2	3	4	0	1	2	3	4
	Accelerated aging (%)					Moisture content after AA (%)
T0	91 Aa^* * Mean values followed by different uppercase letters in each row within each test and by different lowercase letters in each column within each test differ from each other by the Scott-Knott test at the level of 5% probability.	67 Ba	69 Ba	70 Ba	68 Ba	26.1	30.7	28.7	28.6	28.5
T1	76 Ab	64 Ba	68 Ba	65 Ba	50 Cb	27.6	29.5	29.1	28.6	26.9
T2	86 Aa	61 Ba	67 Ba	55 Ba	58 Bb	28.5	28.3	28.3	29.2	31.4
T3	77 Ab	67 Ba	59 Bb	61 Ba	63 Ba	26.9	26.5	27.7	27.7	28.6
T4	68 Ab	60 Aa	57 Ab	63 Aa	58 Ab	28.9	29.6	29.8	29.3	26.8
C.V. (%)	10.4					4.5
	Vigor index					Growth index
T0	807 Aa	737 Ba	553 Ca	612 Ca	496 Ca	806 Aa	662 Ba	507 Ca	593 Ca	474 Ca
T1	724 Aa	696 Aa	566 Ba	547 Ba	502 Ba	693 Ab	739 Aa	520 Ba	504 Ba	484 Ba
T2	624 Ab	719 Aa	623 Aa	577 Ba	492 Ba	568 Bc	694 Aa	591 Ba	549 Ba	472 Ba
T3	583 Ab	580 Ab	480 Ab	487 Ab	513 Aa	542 Ac	518 Ab	410 Ab	457 Aa	460 Aa
T4	556 Ab	417 Bc	431 Bb	492 Ab	440 Ba	502 Ac	354 Bc	370 Bb	457 Aa	393 Ba
C.V. (%)	12.9					14.3
	Root length (cm)					Seedling length (cm)
T0	7.7 Aa	6.2 Ba	4.7 Da	5.6 Da	4.4 Ca	10.9 Aa	9.4 Ba	7.2 Ca	8.3 Ca	6.8 Ca
T1	6.6 Ab	7.0 Aa	4.8 Ba	4.7 Bb	4.6 Ba	9.7 Aa	10.4 Aa	7.5 Ba	7.2 Bb	6.8 Ba
T2	5.3 Bc	6.5 Aa	5.5 Ba	5.1 Ba	4.5 Ba	8.3 Bb	9.9 Aa	8.5 Ba	7.8 Ba	6.6 Ca
T3	5.1 Ac	4.9 Ab	3.8 Ab	4.3 Ab	4.3 Aa	7.9 Ab	7.4 Ab	6.0 Ab	6.4 Ab	6.6 Aa
T4	4.6 Ac	3.3 Bc	3.8 Bb	4.3 Ab	3.6 Ba	7.5 Ab	5.2 Bc	5.5 Bb	6.6 Ab	5.8 Ba
C.V. (%)	14.6					14.1

Brasil

Brasil

Treatment of soybean seeds with mechanical damage: effects on their physiological potential

Abstract:

Impacts	Lot 1		Lot 2
Impacts	ES	UI	FGC	G	ES	UI
0	83 a^* * Mean values followed by different letters in each column within impacts and within seed treatment differ from each other by the Scott-Knott test at the level of 5% probability.	657 a	88 a	91 a	87 a	744 a
1	83 a	634 a	83 b	86 b	81 b	715 a
2	77 b	604 a	80 b	83 b	76 c	652 b
3	74 b	638 a	75 c	79 c	72 c	619 b
4	74 b	590 a	70 d	75 d	68 d	562 c
ST
T0	86 a	719 a	82 a	85 a	80 a	694 a
T1	80 b	690 a	78 b	82 b	77 b	679 a
T2	80 b	645 b	81 a	85 a	79 a	684 a
T3	72 c	585 c	79 b	82 b	75 b	648 a
T4	76 c	484 d	77 b	80 b	73 b	588 b
C.V. (%)	6.8	13.1	6.6	5.5	8.2	12.0