1 September 2005

 

Screening Soybean Varieties for Resistance to Iron Chlorosis, 2005

 

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

e-mail:  rj.goos@ndsu.edu

 

Field studies were set out at five locations in 2005, to measure the resistance of about 180 soybean varieties to iron chlorosis.  The sites were located near Arthur, Ayr, Chaffee, Colfax, and Galesburg, ND.  The sites ranged in pH from 7.8 to 8.1, salinity (EC) from 0.4 to 1.9 mmho/cm, and CaCO3 contents ranging from 2 to 11 %.  Thirty five seeds were planted in short (5Õ) rows on 30-inch centers.  The experimental design was a randomized complete block with four replications at each site. 

 

Visual ratings were made on a 1-5 scale, with 1=representing no chlorosis and 5= the most severe chlorosis.   Ratings were taken at the 2-3 and 5-6 trifoliolate stages.

 

Ten ÒstandardÓ varieties were entered, to help in the interpretation of the results.  The varieties, listed in general order from the most resistant to most susceptible, were Iowa State  ISU A11 > Seeds 2000 2070RR >  Traill = Council > Asgrow 0801 = Peterson PFS 0202RR > Glacier >Mycogen 5072 = Stine 0480 = NuTech 0505RR.  The variety ISU A11 represents the highest level of chlorosis resistance available in current breeding lines. All standards were entered twice, to show the degree of variation in our ratings. 

 

The summary of the chlorosis scores, averaged across site and the three ratings, are shown in Table 1. Each chlorosis rating in Table 1 represents the average of 40 observations.  In general, very good data were obtained in 2005.  Our standard varieties separated themselves out as expected, and reproducibility of our standards was very good.

 

If a field produces temporary chlorosis, a level of chlorosis from which plants normally recover in a week or two, we generally recommend that varieties have a chlorosis resistance in the range of Asgrow 0801 or better.  On fields with more serious chlorosis problems, where yellowing persists, and plants growth is stunted, only varieties with the highest levels of resistance should be planted, consistent with other considerations, such as maturity.  

 

This is the fifth year of this project.  We think that it is appropriate, after five years, to look back at the data that has been generated.  Our recommendations are based the performance of ÒstandardÓ varieties.  We think that it is appropriate, after five years, to look back on the consistency of our data for these standard varieties.

 

Figure 1 shows the chlorosis scores of our standard varieties, averaged across site and time of rating, for each year.  It is important to note that the lines are more-or-less parallel to each other.  In other words, we have observed that the strongest varieties are the strongest varieties, and that the weakest varieties are the weakest varieties.  There is some minor Òcrossing overÓ in ratings, which is likely due to the experimental error involved with doing chlorosis research.

 

 

 

Figure 1.  Average chlorosis scores for our ÒstandardÓ varieties, averaged across site, for the first five years of this project.  North Dakota.

 

 

 

 

 

This report is also available online at:

 

www.yellowsoybeans.com

 

This research was sponsored by the North Dakota Soybean Council.

 

 

 

 

 

 

Table 1.  Average chlorosis scores, across two ratings and five locations, North Dakota, 2005. 

 

Company

Variety

Average

Standards

A11

1.4

Standards

A11

1.5

Asgrow

AG 00603

2.0

Peterson Farm Seed

06004 RR

2.0

Standards

S2000  2070RR

2.1

Stine

0056-4

2.1

Dyna-Gro

30B04

2.1

Ziller

Exp 75103R

2.1

Stauffer

4004 R

2.1

Mycogen

5B004 RR

2.1

Wensman

W20051 RR

2.1

Brushvale

BS 0535 N

2.2

Gold Country

GCS 426 RR

2.2

Legend

LS 0255 RR

2.2

Hyland

HX 254

2.2

Standards

S2000   2070RR

2.2

Stine

0063-4

2.2

Univ.-MN

M98-210060

2.2

Legend

LS 0036 RR

2.3

Stauffer

4020 R

2.3

Stine

0066-34

2.3

Univ.-MN

M00-103043

2.3

ProSeed

RR 50-04

2.3

Croplan

RT 0043

2.3

 

 

 

Company

Variety

Average

Brushvale

BS 0533 N

2.3

Thunder

2502 RR

2.4

Pioneer

90M01

2.4

Stine

0260-4

2.4

Hyland

RR Reliant

2.4

Asgrow

AG 0401

2.4

Gold Country

GCS 926 RR

2.4

Wensman

W2020 RR

2.4

Standards

Traill

2.5

Standards

Council

2.5

ProSeed

RR 50-06

2.5

Thunder

2501 RR

2.5

Gold Country

GCS 825 RR

2.5

Standards

Traill

2.5

Production Partners

0099 RR

2.5

Legend

LS 0045 RR

2.5

Sabre

0624 RR

2.5

Standards

Council

2.5

Pioneer

90M60

2.6

Legend

LS 0093 RR

2.6

Asgrow

AG 0301

2.6

Kaystar

K-0520 RR

2.6

ProSeed

RR 50-07

2.6

Ziller

BT 7102R

2.6

 

 

 

Company

Variety

Average

Mallard

RR 0212

2.6

Univ.-MN

M98-211117

2.6

Stine

0090-64

2.6

Asgrow

AG 0202

2.6

Midwest Seed Genetics

GR 0504

2.6

Stine

0070-64

2.7

Garst

1226 RR

2.7

Thunder

26009 RR

2.7

Hyland

HX 54001 RR

2.7

NuTech

NT-0090 RR

2.7

Mycogen

X55009 RR

2.7

NorthStar

NS 0620 RR

2.7

Legend

LS 0624 RR

2.7

Dyna-Gro

30M09

2.7

Croplan

RT 0273

2.7

Wensman

W20092 RR

2.7

Peterson Farm Seed

06006RR

2.7

NuTech

NT-0121+ RR

2.7

Standards

PFS  0202 RR

2.7

ProSeed

RR 40-71

2.7

NorthStar

NS 00990RR

2.7

NorthStar

NS 0130 RR

2.7

NorthStar

NS 0911 RR

2.7

Croplan

RT 0669

2.7

 

 

 

 

 

 

Company

Variety

Average

ProSeed

RR 50-00

2.7

Kruger Seed

K-009+RR

2.7

Prairie Brand

PB-00965 RR

2.7

Dairyland

DST C9-000/RR

2.8

Univ.-MN

M99-230063

2.8

Standards

PFS  0202 RR

2.8

Thunder

26005 RR

2.8

Gold Country

GCS Sonora

2.8

Hyland

RR Royal

2.8

Sabre

0061

2.8

Standards

Asgrow  0801 RR

2.8

Univ.-MN

M00-108066

2.8

Sabre

0092

2.8

Wensman

W20077 RR

2.8

Dairyland

DSR-0501/RR-STS

2.8

ProSeed

RR 50-10

2.8

Prairie Brand

PB-0554 RR

2.8

NorthStar

NS 0110 RR

2.8

Production Partners

0444+ RR/STS

2.8

Peterson Farm Seed