Screening Soybean Varieties for Resistance to Iron Chlorosis, 2001

R. Jay Goos and Brian Johnson, Department of Soil Science, NDSU, Fargo, ND 58105

e-mail: rj.goos@ndsu.nodak.edu

Field studies were conducted at four locations in 2001, to compare the chlorosis resistance of 181 soybean varieties to iron chlorosis. The four sites were located near Amenia, Argusville, Ayr, and Galesburg. The sites ranged in pH from 8.0 to 8.2, salinity (EC) from 0.4 to 2.0 mmho/cm, and CaCO₃ content from 5.7 to 11.9%. The varieties were planted in short (5’) rows on 30-inch centers. The experimental design was a randomized complete block with four replications.

Three ratings were made, at the 2-3 trifoliolate stage, the 5-6 trifoliolate stage, and two weeks after the 5-6 trifoliolate stage. The scale was a 1-5 scale, with 1=representing no chlorosis and 5= severe chlorosis. The third rating was not taken at the Galesburg site, because field variability began to develop after the 5-6 trifoliolate stage.

Four "standard" varieties were also entered, to help in the interpretation of the results. The varieties, listed in order from the most resistant to most susceptible, were Traill, Council, Glacier, and Mycogen 5072. The varieties Traill, Council, and Glacier were included twice, to also help us determine the reproducibility of our rating system.

The summary of the chlorosis scores, averaged across site and the three rating times, are shown in Table 1. Getting good results with field research with iron is not easy, as there can be a lot of field variability. However, we were very pleased with how well the trials went in 2001. Our "standard" varieties separated themselves as we expected, and we were able to reproduce the scores of the standard varieties by about 0.1 chlorosis unit. Each chlorosis rating in Table 1 represents the average of 44 observations.

From our experience with chlorosis in the field, we generally recommend that varieties have a chlorosis resistance as good or better than Council for chlorosis-prone soils. Of the 181 varieties tested, about 40 meet that criterion. This indicates that, for fields prone to chlorosis, farmers need to be very selective in the varieties they grow. Any yield advantage of a less-resistant variety is lost if the crop turns yellow, even if there is recovery later in the growing season.

Please contact us by mail or e-mail if you want more information. In early September, a more complete report of our 2001 chlorosis studies, with detailed soil analyses and chlorosis scores by site will be available. The report will be made available at that time at the following web address:

This research was sponsored by the North Dakota Soybean Council.

Table 1. Average chlorosis scores, four site averages, North Dakota, 2001. 1=least chlorosis, 5=most chlorosis.

		Average				Average
Company	Variety	chlorosis		Company	Variety	chlorosis
U. of MN	MN 0302	1.6		Mustang	M-093 RR	2.3
Seeds 2000	2070 RR	1.8		Stine	S0806-4	2.3
Pioneer	P 90B43	1.8		Seeds 2000	2081 RR	2.3
Standard	Traill	1.9		Thunder	2109 RR	2.3
Top Farm	TF 6101	1.9		Wensman	W 2092 RR	2.3
King Grain	KG-20	1.9		NuTech	NT-0777 RR	2.3
Hyland	RR Rally	1.9		Asgrow	AG 0801	2.3
Mycogen	5007	1.9		Mallard	RR 0913	2.3
Kaystar	K-0760 RR	2.0		Mycogen	5121	2.4
NDSU	Traill	2.0		U. of MN	M94-175050	2.4
U. of MN	MN 0201	2.0		Mustang	M-082 RR	2.4
Wensman	W 2095 RR	2.0		Hyland	Corona	2.4
Gold Country	GCS-6009 RR	2.0		U. of MN	M92-185003	2.4
Wensman	W 2054 RR	2.0		NDSU	Walsh	2.4
Standard	Traill	2.0		NDSU	Norpro-Rps6	2.4
Prairie Brand Seed Co.	PB-0321 RR	2.0		Hyland	RR Richland	2.4
NorthStar	NS 0714 RR	2.0		U. of MN	MN 0902 CN	2.4
SDSU	SD96-702	2.1		NDSU	Jim	2.5
Dyna-Gro	3074 RR	2.1		NDSU	Danatto	2.5
NDSU	Council	2.1		NDSU	ND97-1120	2.5
Wensman	W 2081 RR	2.1		NDSU	Daksoy	2.5
Pioneer	Exp 03	2.1		NorthStar	NS 0805 RR	2.5
Garst	XR 0105 P01	2.1		Thunder	2108 RR	2.5
Peterson Farms Seed	0009 RR	2.1		U. of MN	M92-285024	2.5
Gold Country	GCS-3205 RR	2.2		Syngenta	NK Brand S04-E1	2.5
Mallard	0910	2.2		Top Farm	TF E1091 A RR	2.5
Brushvale	B.S. 9908 N	2.2		Brushvale	B.S. 9960 P	2.5
Garst	X 0108 P70	2.2		Kaltenberg	KB081 RR	2.5
Thunder	607 RR	2.2		Seeds 2000	2110 RR	2.5
Peterson Farms Seed	0006 RR	2.2		Prograin	PR 0121 RR	2.5
Midwest Seed Genetics	GR 0955	2.2		Prograin	PR 9901	2.6
Standard	Council	2.2		Hyland	T 9801	2.6
Kaystar	K-0960 RR	2.2		Dairyland Seed	DSR-101/RR	2.6
NDSU	Traill RR	2.2		Gold Country	GCS-4107 RR	2.6
NorthStar	NS 0905 RR	2.2		Dyna-Gro	3086 RR	2.6
Dekalb	DKB 09-51	2.2		Syngenta	NK Brand S06-L6	2.6
Kaystar	K-0520 RR	2.2		AgriPro	1394	2.6
Standard	Council	2.3		Thunder	2030	2.6
Mallard	RR 0912	2.3		Prograin	PR 5001.14	2.6
Syngenta	NK Brand S10-F2	2.3		Gold Country	GCS-3202 RR	2.6

Table 1 (continued).

		Average				Average
Company	Variety	chlorosis		Company	Variety	chlorosis
Pioneer	Exp 07	2.6		Syngenta	NK Brand X1002R	3.0
NDSU	ND97-962	2.6		Hyland	Cass	3.0
Asgrow	AG 0901	2.7		Stine	S0300-4	3.0
Thompson Agri	TR-077	2.7		Stine	S0090-4	3.1
Wensman	W 2086 RR	2.7		Top Farm	TF E1051 RR	3.1
Kaystar	K-0740 RR	2.7		Pioneer	P 91B33	3.1
Richland Organics	MK 0649 N	2.7		Mustang	M-101 RR	3.1
Wensman	W 2025 RR	2.7		Thunder	2106 RR	3.1
Richand Organics	MK 917 N	2.7		Proseed	OO79 RR	3.1
NDSU	Barnes	2.7		U. of MN	M94-147018	3.1
Dairyland Seed	DSR-065	2.7		Mustang	M-079 RR	3.1
Gold Country	Bygland	2.7		Syngenta	NK Brand S00-N7	3.1
Standard	Glacier	2.8		Top Farm	TF 6038	3.1
Standard	Glacier	2.8		Prairie Brand Seed Co.	PB-0550 RR	3.2
Golden Harvest	X 11091RR	2.8		Proseed	OO69 RR	3.2
Midwest Seed Genetics	GR 1100	2.8		Mycogen	Atlas 5050 RR	3.2
Pioneer	Exp 10	2.8		Dairyland Seed	DST-0810	3.2
Mallard	RR 1011	2.8		Stine	S0300-0	3.2
Garst	X 0113 Y71	2.8		Dyna-Gro	3072 RR	3.2
Prograin	PR 9935	2.8		NDSU	Sargent	3.2
Pioneer	P 90B72	2.8		Brushvale	B.S. 9941 N	3.2
Pioneer	P 91B52	2.8		Kaystar	K-0755 RR	3.2
U. of MN	M94-135066	2.8		Golden Harvest	X 10544RR	3.2
Prograin	OAC Vision	2.9		Prograin	PR 5027.42	3.2
Prograin	PR 5005.83	2.9		Mycogen	B 076 RR	3.2
Mycogen	'013	2.9		Dekalb	DKB 06-51	3.2
Dairyland Seed	DSR-010	2.9		Thunder	2200 RR	3.2
Wensman	W 2131 RR	2.9		Top Farm	TF 6020 RR	3.2
Peterson Farms Seed	0007 RR	2.9		Pioneer	P 91B12	3.3
Dairyland Seed	DSR-130/RR	2.9		Mallard	RR 0512	3.3
NorthStar	NS 0314 RR	2.9		Gold Country	GCS-2105 RR	3.3
Thompson Agri	TR-0222 RR	2.9		Dekalb	DKB 03-51	3.3
Peterson Farms Seed	Korada	3.0		Mustang	M-052 RR	3.3
Mustang	M-021 RR	3.0		NorthStar	NS 0001	3.3
Gold Country	GCS-00872 RR	3.0		Richland Organics	MK 1009 HP	3.3
Mallard	RR X 1312	3.0		Richland Organics	MK 9532	3.3
Dairyland Seed	DSR-030/RR	3.0		SK Foods	SK 214 N	3.3
Dekalb	DKB 10-51	3.0		NorthStar	NS 0505 RR	3.3
Mycogen	5081	3.0		NuTech	NT-0504 RR	3.3
Golden Harvest	H-0537RR	3.0		Golden Harvest	H-0440	3.3

Table 1 (continued).

		Average
Company	Variety	chlorosis
U. of MN	Proto	3.3
Brushvale	B.S. 9910 P	3.3
NDSU	Norpro	3.3
Thunder	2203 RR	3.3
Syngenta	NK Brand S02-G2	3.3
Gold Country	GCS-6805 RR	3.3
Peterson Farms Seed	0105 RR	3.4
Dairyland Seed	DSR-061	3.4
Gold Country	GCS-1207 RR	3.4
Top Farm	TF 6059 RR	3.4
Syngenta	NK Brand S08-R4	3.4
Midwest Seed Genetics	GR 0525	3.4
Prograin	PR 014109 RR	3.5
Dairyland Seed	Experimental	3.5
Gold Country	GCS-X3203	3.5
NuTech	NT-0505 RR	3.5
Mycogen	Atlas 5097 RR	3.5
Standard	Mycogen 5072	3.6
Golden Harvest	H-0979RR	3.6
Mustang	M-051RR	3.7
Thompson Agri	TR-0808 RR	3.7
Mallard	RR 1311	3.7
NorthStar	NS 0205 RR	3.7
Prograin	PR 0101 RR	3.7
Seeds 2000	2020 RR	3.7
Dyna-Gro	3098 RR	3.8