Germplasm Enhancement of Maize

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Objective
Methods
Results
Conclusions
Table 1
Table 2
Table 3
Figure 1

GEM - 2005 Public Cooperator's Report

NOTE: The information in this report is shared cooperatively. The data are not published, but are presented with the understanding that they will not be used in publications without specific consent of the public cooperator.

 

Amino Acid analysis of GEM germplasm

Paul Scott and Merinda Struthers

USDA-ARS, Ames, Iowa

Objective:  To identify germplasm with superior amino acid content.

Methods:

We have analyzed about 70 GEM accessions each year for the past year for their content of the nutritionally limiting amino acids tryptophan, lysine and methionine.  We use a microbial method (Scott et al., 2004) that is suitable for ranking samples.  The inbred line B101 was included as a high methionine check and B45o2 was included as a high lysine and tryptophan check.  B73, Mo17 and B73xMo17 were included as normal checks.

Results:

The four year data are summarized in Table 1.  The methionine content of one GEM entry was not significantly different than the high methionine check and the lysine content of one entry was not significantly different than the high lysine check.  Tryptophan showed no significant variation among the GEM entries, and all were significantly lower than the high tryptophan check.  In the index ranking, two GEM entries were significantly higher (about 15%) than the B73xMo17 normal check.

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Table 1:  Pedigrees with four years of data.

Pedigree

Met

Trp

Lys

Index

B101

A

B

BC

B

2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib-B

AB

B

BC

B

DKXL212:N11a-139-1-1-B-B-B

BC

B

ABC

B

FS8B(S):S0316-814-1-B-B

C

B

C

BC

AR16035:S02-450-1-B-B-B-B

C

B

C

BC

B45 o2

D

A

A

A

B73 x Mo17-B

D

B

BC

C

FS8B(T):N1802-382-1-B-B

D

B

BC

BC

Mo17

D

B

AB

BC

Entries not connected by the same letter are significantly different. A is the highest ranked grouping, and rankings decrease in alphabetic order.

Index weights Met, Lys and Trp equally. 

Pedigrees with three years of data are summarized in Table 2.  The methionine content of one GEM pedigree was not significantly different than the high Methionine check.  Tryptophan showed no significant variation among the GEM entries, and all were significantly lower than the high tryptophan check.  The lysine content of one GEM entry was not significantly different from the high lysine check.  Significant differences were not found among GEM entries for the index, and B45o2 was significantly higher than other entries.

Table 2:  Pedigrees with three years of data.

Pedigree

Met

Trp

Lys

Index

B101

A

B

BC

B

CH05015:N1204-057-001-B-B-B

AB

B

ABC

BC

CUBA117:S15-372-1-B-B-B

B

B

C

BC

B73

B

B

C

BC

CH05015:N15-003-1-B-B-B-B

BC

B

C

BC

CH05015:N12-183-1-B-B-B-B

BCD

B

C

BC

2088-01_DK212T_S11_F2S4_9157-Blk29/00-sib-B

BCD

B

BC

BC

2152-02_DK888_S11_F2S4_9202-Blk24/00-sib-B

BCD

B

C

BC

GUAT209:N1925-081-1-B/AR16035:S19-161-1-B-B

BCD

B

C

C

CHIS775:N1912-651-1-B-B-B-B

CDE

B

C

C

CHIS775:S1911b-120-1-B-B-B

DE

B

C

C

BR52051:N04-070-1-B-B

DEF

B

BC

BC

B45 o2

EF

A

A

A

B73 x Mo17-B

EFG

B

BC

C

BR52051:N04-076-1-B-B

FG

B

C

C

Mo17

G

B

AB

BC

Entries not connected by the same letter are significantly different.  A is the highest ranked grouping, and rankings decrease in alphabetic order.

Index weights Met, Lys and Trp equally. 

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A number of GEM entries did well in the 2005 trial.  DKXL380:S11 F2S4 2282 and 1881-002/98_DKXL370AN11F2S3_7521-05 had significantly more methionine than the high methionine check.  In addition, the following entries were not significantly different from the high methionine check, but were significantly higher than the normal checks.

1883-002/98_DKXL370AN11F2S3_7521-05-B
(2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib)-B-B
1883-001/98_DKXL370AN11F2S3_7521-05-B
1895-001/98_DKXL370AN11F2S3_7521-29-B
2410-003/99_SCRGp3N14F2S3_7258-3-B
1886-003/98_DKXL370AN11F2S3_7521-05-B
CHIS740:S1411a-783-002-B-B-B-B

FS8B(T):N1802-382-001-B-B-B-B was significantly higher in tryptophan than all other GEM entries, but the high tryptophan check was higher than everything in the trial.  Given the limited variability we have seen for tryptophan, this entry will be important to test in future years.  

MDI022:N2120-253-001-B-B was significantly higher in lysine than other GEM entries, although it was not as high as the high lysine check. 

The top quartile of the entries ranked by index is listed in Table 3.  Many of these entries have not been tested before and will be included in subsequent tests.

Table 3:  Top Quartile of entries ranked by Index

Pedigree

Index Value

B45o2

5.20

1883-002/98_DKXL370AN11F2S3_7521-05-B

3.91

MDI022:N2120-253-001-B-B

3.66

1895-001/98_DKXL370AN11F2S3_7521-29-B

3.58

DKXL380:S11 F2S4 2282-01)-Sib-B-B-B

3.48

1886-003/98_DKXL370AN11F2S3_7521-05-B

3.37

2423-017/99_DKXL380N11F2S3_7541-10-B

3.30

UR11003:S0302-1011-001-B-B-B

3.29

1883-001/98_DKXL370AN11F2S3_7521-05-B

3.28

DKXL212:N11a-139-1-1-B-B-B

3.27

CHIS740:S1411a-783-2-B-B-B

3.25

2410-003/99_SCRGp3N14F2S3_7258-3-B

3.23

Mo17

3.18

DREP150:N2011d-624-1-B-B

3.12

2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib-B

3.10

Index weights methionine, lysine and tryptophan equally, and the mean for the trial is 3.00

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Conclusions:

GEM germplasm has been identified that shows promising levels of methionine, lysine and overall quality.  It will be important to evaluate the protein content of this germplasm and to conduct multiyear evaluations on germplasm new to the study.  Several entries from these studies have been released as GEM lines (Figure 1)

SCOTT, M.P., S. BHATNAGER and J. BETRAN, 2004 Tryptophan and methionine levels in quality protein maize breeding germplasm. Maydica. 49: 303-311.

Figure 1:  3 year data from 2004 analysis of protein quality index.

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We are grateful to our Cooperators for their support!

 


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Contact us | Home | USDA | ARS | NCRPIS | ISU | Corn Breeding | January 25, 2006