Maize Genetics Cooperation Newsletter vol 84 2010
Please Note: Notes submitted to the Maize Genetics
Cooperation Newsletter may be cited only with consent of authors.
Ottawa, Ontario, Canada
Eastern Cereal and Oilseed Research Centre
Ya�an, Sichuan, China
Sichuan Agricultural University
Heterotic Groups of Canadian Maize Inbred Lines Based on Pedigree and SSR Markers
Reid, L.M., X. Zhu, B. Bernard, K. Xiang, C. Voloaca, and T. Woldemariam
Corn breeders of Agriculture and Agri-Food Canada (AAFC) have collected maize genotypes from around the world and adapted them to the different short growing season regions of Canada. In many cases, the heterotic backgrounds of these genotypes were unknown, while others had been developed from mix of two or more heterotic groups. In the early years of inbred development at AAFC, testers of known heterotic backgrounds were not available with maturities suitable to Canadian climates. This sometimes resulted in the release of inbreds with little knowledge on their combining ability with the different heterotic patterns. Over the past few years, we have been evaluating the inbred lines released from AAFC during the last 20 years and classifying them into known heterotic groups based on pedigree and Simple Sequence Repeat (SSR) markers.
A total of 129 inbred lines were classified into nine groups based on pedigree (Table 1). Eighteen inbred lines with five major sources (BSSS, B73, B14, B37, and BSTE) were categorized into Group I (BSSS group); 19 inbred lines with three major sources (Inra 258, Pfister 44 and Lethbridge Gene Pool) were classified into Group II (European flint group); Group III (Lancaster group) included 15 inbred lines with the major sources of MO17, OH43, LH83, W153 and H99; Group IV (Minnesota #13 group) consisted of seven inbred lines with the major source of Minnesota #13 and Pride 5; Group V (Early Butler group) consisted of seven inbred lines; Group VI (Iodent group) consisted of four inbred lines; Group VII (Pioneer 3990 group) consisted of 11 inbred lines; Group VIII (Pioneer 3994 group) consisted of 13 inbred lines; and 35 inbred lines with no major sources were classed as Group IX.
The 129 inbred lines analyzed
with 105 SSR primers were distributed across the 10 maize chromosomes, with an
average of 10.5 primes per chromosome. A total of 380 alleles were detected with
2 to 7 per locus, with an average of 3.62. The results indicated that such variation was significantly associated
with the number of alleles detected. Cluster analysis
was carried out based on the matrix of genetic similarities using the Unweighted Pair Group Method Using Arithmetic Average
clustering algorithm using NTSYS-pc version 2.2 (Exeter Software New York, USA). All the inbred
lines were classified into 13 groups (Table 1).
When comparing the pedigree groups with the SSR groups, the two groupings were basically identical for the majority of the inbred lines (Table 1). The results showed that there were two to six SSR groups per pedigree group, while group VII included two SSR groups and the group VIII included six groups.
Ordinations were conducted by using canonical discriminant analysis (Kshirsagar, Multivariate analysis. 1972) and classification probabilities by carrying out classificatory discriminant analyses (Fig. 1). The analyses were performed using SAS (SAS Institute, Inc 1989) version 9.1.3 (2007). Comparing the groups based on the discriminant analysis of SSR data with the pedigree groups, the inbred lines in the ninth pedigree group with unknown sources were classified into eight other groups (Table 1), some inbred lines in the same pedigree group were classified into different groups. According to the cross-validation results, this classification was 94.7% probability reliable.
We are currently conducting further classification analysis based on combining ability data of these inbreds with testers of known heterotic patterns.
Table 1. Major pedigree and three types of classifications of 129 maize inbred lines released by AAFC (inbreds prefixed with CB, CL, CM or CO) and several check inbreds.
|
Major pedigree |
Pedigree group� |
SSR cluster group� |
|
B73 |
BSSS/B73 |
I |
I |
|
CM105 |
B14 |
I |
I |
II |
CM174 |
B14 |
I |
I |
II |
CO269 |
BSSS |
I |
I |
XII |
CO360 |
B37/B14/Minnesota#13 |
I |
I |
II |
CO362 |
B14 |
I |
I |
II |
CO363 |
B14 |
I |
I |
II |
CO364 |
B14 |
I |
I |
XII |
CO370 |
BSTE |
I |
I |
VI |
CO388 |
B73/BSTE/Early Butler |
I |
I |
XII |
CO389 |
B73/BSTE/Early Butler |
I |
I |
IX |
CO408 |
B37/Pfister44 |
I |
I |
XII |
CO434 |
B14 |
I |
I |
|
CO435 |
B14 |
I |
I |
XII |
CO439 |
BSSS |
I |
I |
II |
LH300 |
B14 |
I |
I |
II |
MBS1236 |
B14/Pioneer 3978 |
I |
I |
VI |
TR4033 |
B14 |
I |
I |
II |
CL30 |
European flint |
II |
V |
|
CO251 |
Pfister44/Early Butler |
II |
II |
XII |
CO255 |
Inra 258 |
II |
XIII |
|
CO343 |
MO17/Inra 258 |
II |
III |
XII |
CO344 |
MO17/Inra 258 |
II |
II |
XII |
CO345 |
Pfister44/Inra 258/OH43 |
II |
II |
XIII |
CO349 |
Inra 258/B14 |
II |
II |
XII |
CO365 |
Pfister44/BSSS |
II |
II |
XII |
CO382 |
Inra 258/MO17 |
II |
II |
XIII |
CO383 |
Inra 258/MO17 |
II |
II |
XII |
CO384 |
Inra 258/B14 |
II |
II |
XII |
CO409 |
Inra 258/Pioneer 3977 |
II |
II |
XIII |
CO412 |
Inra 258/OH43/B14 |
II |
II |
XII |
CO414 |
Inra 258/B14 |
II |
II |
XII |
CO416 |
Pfister 44/B14 |
II |
II |
|
CO418 |
European hybrids |
II |
II |
VI |
CO422 |
Inra 258/OH43/B14 |
II |
II |
XII |
CO437 |
European hybrids |
II |
II |
VII |
LH290 |
Pioneer 3978/F2 |
II |
II |
XIII |
CO359 |
W153R/LH82 |
III |
VI |
|
CO367 |
W153R/LH82 |
III |
III |
VI |
CO368 |
W153R/LH82 |
III |
III |
VI |
CO369 |
W153R/LH82 |
III |
VI |
|
CO386 |
MO17/MAG |
III |
I |
IV |
CO390 |
H99/OH43 |
III |
III |
XIII |
CO393 |
Pioneer 3990/MO17 |
III |
III |
IV |
CO394 |
Pioneer 3990/MO17 |
III |
III |
IV |
CO395 |
Pioneer 3990/MO17 |
III |
III |
IV |
CO427 |
OH43/H99 |
III |
III |
IV |
CO428 |
OH43/H99 |
III |
V |
XII |
CO429 |
W153R/LH82 |
III |
III |
VI |
LH176 |
LH82/Pioneer 3704 |
III |
III |
XIII |
Mo17 |
MO17 |
III |
III |
IV |
OH43 |
OH43 |
III |
III |
XIII |
CB21 |
Pfister 44/Minnesota #13 |
IV |
||
CO106 |
Minnesota #13 |
IV |
IV |
X |
CO303 |
Pride 5/BSSS |
IV |
IV |
XII |
CO328 |
Pride 5/BSSS |
IV |
IV |
XII |
CO350 |
Pride 5/Pioneer 3977 |
IV |
IV |
III |
CO415 |
Pride 5/Pioneer 3968 |
IV |
IV |
III |
CO440 |
Pride 5/BSSS |
IV |
IV |
III |
CO220 |
Early Butler |
IX |
||
CO325 |
Early Butler/BSSS |
V |
V |
|
CO346 |
Early Butler |
V |
V |
XI |
CO361 |
BSSS/BSTE/Early Butler |
V |
VII |
XII |
CO387 |
Pioneer 3990/BSTE/ Early Butler |
V |
V |
|
CO424 |
BSSS/ Early Butler |
V |
V |
XII |
CO443 |
BSSS/ Early Butler |
V |
V |
|
CO421 |
Iodent/F2 |
VI |
VI |
III |
CO442 |
Iodent |
VI |
VI |
III |
LH162 |
Iodent/MO176 |
VI |
VI |
IV |
TR1957 |
Iodent |
VI |
||
CO266 |
Pioneer 3990 |
VII |
VII |
IV |
CO289 |
Pioneer 3990 |
VII |
IV |
|
CO377 |
Pioneer 3990 |
VII |
VII |
XII |
CO378 |
Pioneer 3990 |
VII |
VII |
IV |
CO380 |
Pioneer 3990 |
VII |
VII |
IV |
CO381 |
Pioneer 3990 |
VII |
VII |
|
CO396 |
Pioneer 3990/Inra 258/BSSS |
VII |
VII |
XII |
CO397 |
Pioneer 3990/Inra 258/BSSS |
VII |
VII |
IV |
CO398 |
Pioneer 3990/Inra 258/BSSS |
VII |
VII |
IV |
CO406 |
Pioneer 3990 |
VII |
VII |
XII |
CO407 |
Pioneer 3990 |
VII |
IV |
|
CB12 |
Pioneer 3994 |
VIII |
VIII |
III |
CO341 |
BSSS/Pioneer 3994 |
VIII |
VIII |
V |
CO366 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
III |
CO375 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
XII |
CO376 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
III |
CO403 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
XII |
CO404 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
XIII |
CO405 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
XIII |
CO410 |
BSSS/Pioneer 3994 |
VIII |
VI |
|
CO417 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
IV |
CO425 |
BSSS/ Pioneer 3994 |
VIII |
VIII |
VI |
CO436 |
Pioneer 3994/Minnesota #13 |
VIII |
VIII |
III |
CO438 |
Pioneer 3994/Unknown |
VIII |
VIII |
III |
Unknown |
IX |
II |
V |
|
CO342 |
Unknown/Ottawa
flint/Minnesota#13 |
IX |
III |
|
CO347 |
Unknown |
IX |
III |
|
CO348 |
Unknown |
IX |
VI |
|
CO351
|
Unknown/Ottawa
flint/Minnesota#13 |
IX |
V |
VII |
CO352 |
Asgrow RX777 |
IX |
I |
|
CO353 |
Asgrow RX777 |
IX |
I |
XII |
CO354 |
Asgrow RX777 |
IX |
I |
I |
CO355 |
Pioneer 3389 |
IX |
III |
I |
CO356 |
Pioneer 3389 |
IX |
V |
I |
CO357 |
Pioneer 3389 |
IX |
III |
IV |
CO358 |
Pioneer 3389 |
IX |
V |
XII |
CO371 |
Unknown |
IX |
IV |
VIII |
CO372 |
Unknown |
IX |
II |
XIII |
CO373 |
Unknown |
IX |
IV |
XIII |
CO374 |
Unknown |
IX |
II |
|
CO379 |
Unknown |
IX |
V |
III |
CO385 |
Unknown |
IX |
II |
VI |
CO391 |
Asgrow RX777 |
IX |
I |
I |
CO392 |
Ottawa
flint/Minnesota#13/OH43/B14 |
IX |
II |
XII |
CO399 |
Pioneer 3925 |
IX |
IV |
VI |
CO400 |
Pioneer 3925 |
IX |
IV |
VI |
CO401 |
Unknown |
IX |
VIII |
V |
Unknown |
IX |
VIII |
VII |
|
CO411 |
Pioneer 3995 |
IX |
II |
III |
CO413 |
Pioneer 6124/Pioneer
3968 |
IX |
VII |
V |
CO419 |
Unknown |
IX |
IV |
V |
CO420 |
Unknown |
IX |
VI |
V |
CO423 |
Unknown |
IX |
V |
III |
CO426 |
Unknown |
IX |
III |
VI |
CO430 |
Unknown |
IX |
VII |
IV |
Unknown |
IX |
VI |
IV |
|
CO432 |
Unknown |
IX |
IV |
VI |
CO433 |
Pride K127 |
IX |
IV |
VI |
CO441 |
Unknown |
IX |
III |
VI |
�
Groups based on the pedigree.
�
Groups based on the discriminant analysis of SSR data.
�
Groups based on the genetic similarities using the Unweighted
Pair Group Method Using Arithmetic Average clustering algorithm.
Fig. 1 Canonical discriminant analyses of
the SSR markers. 1 = BSSS group; 2 = European
flint group; 3 = Lancaster group; 4 = Minnesota #13 group; 5 = Early Butler
group; 6= Iodent group; 7= Pioneer3990 group; 8= Pioneer
3994 group.