1. Cotton Breeding At Auburn University
David B. Weaver, Professor
Department of Agronomy & Soils
Alabama Crop Improvement Association
February 25, 2013

2. Objectives of the program
Cultivar development – Development of new cotton varieties for Alabama and Southeastern cotton growers (40%)
Research in cotton breeding and production (60%):
Development and testing of sources of genetic resistance to reniform nematode (Rotylenchulus reniformis)
Evaluating germplasm and breeding for heat tolerance in cotton
Evaluating for resistance to Target spot (Corynespora cassiicola)

3. U.S. Cotton yield,
b = 14.0
b = 7.44
b = -1.14
Source: USDA-NASS, 2012

4. Alabama Cotton Facts
Alabama ranks 8th among US cotton producing states (tied with Missouri)
700,000 bales produced in 2012*
Up from 685,000 bales in 2011
377,000 acres
4th most important row-crop in US
Most important industrial crop; fiber and oilseed
* A record yield of 952 lbs/acre

5. Cultivar development
Year 1 – crosses made between elite public parents and breeding lines. F1 generation grown in Mexico.
Year 2 – F2 population grown in bulk.
Year 3 – F3 population grown in bulk.
Year 4 – F4 population grown in bulk. Single plants harvested.
Year 5 – F4:5 lines grown in progeny rows. Phenotypic evaluation, fiber quality evaluation.
Fiber quality evaluated mainly based on Q-score, a combination of HVI fiber traits including length, strength, micronaire, uniformity: emphasis is on fiber strength.

6. Cultivar development (con’t)
Year 6 – F4:6 lines tested for yield and fiber quality at 1 location (Tallassee, AL).
Year 7 – Selected F4:7 lines tested at multiple locations in Alabama.
Year 8 – Top 3 or 4 lines entered into Regional Breeders Testing Network. Continued limited testing in Alabama.
Year 9 – Continued testing in RBTN; seed increase for possible release; entry into Alabama Variety Tests; fiber quality tests continue.
Year 10 – Candidate lines considered for release as cultivars.

7. Regional Breeders Testing Network
Cotton RBTN participant – Coordinated by Cotton Incorporated
Network of public cotton breeders throughout the US
Testing and exchange of elite cotton germplasm
Nine+ locations
Primary evaluation criteria are yield, fiber quality
Major vehicle of public cotton cultivar release
Univ. of Arkansas has released 3 (and we hope to have one soon)

8. Regional Breeders Testing Network Locations

9. Table 1. Least square means for lint yield, yield components, and fiber quality traits over 13 locations in the 2011 RBTN.
Cultivar
Lint Yield†
Lint Percent
Lint Index
Boll Size
Seed per Boll
Seed Index
MIC
UHM UI
STRN
ELO
SFC
QS1‡
QS2‡
lbs/a %
grams #
mic
g/tex LA
1400
43.68
7.31
4.76
28.42
9.32
5.08
1.15
83.71
32.43
5.35
6.93
52.15
64.90
AU3111
1388
43.90
7.48
5.02
29.52
9.46
5.04
1.14
82.99
30.50
4.85
7.43
48.42
58.81
MD 25-27Y
1371
40.89
7.18
5.42
30.98
10.29
4.57
84.57
33.08
4.46
6.86
63.87
74.37
DP 393
1340
41.30
7.08
5.00
29.26
9.94
4.99
1.13
83.90
32.87
6.24
6.88
49.42
66.60
AU3202
1335
41.59
7.52
26.38
10.47
5.18
83.83
30.64
7.13
51.44
61.55
Ark
1333
42.52
7.11
29.94
9.51
4.90
83.61
31.08
5.77
7.09
51.46
63.71
NM08N1562
1315
39.37
6.42
4.55
28.20
9.79
4.68
1.17
83.75
31.55
5.37
7.22
62.38
67.83
AU3223
1313
43.60
7.28
4.86
29.16
9.29
83.43
29.95
5.82
48.33
59.33
MD 25-87Y
1304
39.11
5.62
29.49
11.53
4.66
1.18
84.93
37.04
4.44
6.67
73.23
83.92
AU3095
1298
43.19
7.58
28.49
9.86
1.16
83.46
29.72
5.09
55.12
60.73
MD 25-26ne
1293
39.58
6.96
5.45
31.05
10.52
4.59
1.23
85.45
34.63
5.12
6.59
87.38
85.37
SG 105
1279
40.27
7.15
28.31
10.48
5.17
84.11
31.24
5.43
6.83
48.23
65.88
NM08N1564
1276
38.86
6.37
4.75
29.29
9.92
4.82
32.48
5.30
7.23
59.54
67.63
NM08N1084
1269
40.57
6.66
4.65
28.47
9.65
83.65
34.20
5.10
7.06
55.98
68.67
Ark
1267
42.43
5.03
28.54
10.04
4.78
83.59
31.69
4.33
7.19
66.08
67.46
Tamcot 73
1264
39.42
6.87
29.24
10.44
4.87
84.27
34.98
5.15
6.85
64.98
74.35
Ark
1249
40.86
7.30
5.38
30.17
83.97
31.28
4.64
7.10
58.54
65.85 LA
1231
42.02
7.76
5.44
10.54
4.95
84.13
31.77
6.05
6.97
62.21
69.60
PD 05070
1205
41.09
6.99
5.05
29.83
9.93
83.34
32.85
53.35
64.17
PD 06001
1194
38.10
6.61
29.40
10.60
83.45
32.13
7.25
63.73
66.90
FM 958
1167
40.23
7.71
28.24
11.23
4.83
83.96
33.75
3.90
59.21
70.15
NC08AZ21
1144
38.35
6.15
4.54
28.41
9.74
83.14
29.82
5.31
7.47
45.65
55.19
Ark M222-07
1134
40.21
5.01
27.59
10.76
5.13
83.77
31.06
4.71
49.19
62.40
PD 05069
1120
40.99
7.40
5.36
29.81
10.57
4.96
35.31
4.79
6.94
73.46
Acala
1119
38.21
10.97
4.73
1.21
84.24
36.62
6.80
77.67
80.65
Ark
1112
39.80
7.34
5.75
31.25
11.00
4.60
1.19
84.09
33.97
4.49
72.96
74.38 GA
1074
43.62
7.36
4.70
27.92
9.41
32.69
3.96
7.24
63.25
68.08
Mean
1252
40.88
7.14
5.06
29.09
10.21
83.88
32.57
7.07
59.62
68.22
LSD (.05) 72
0.43
0.19
0.14
0.92
0.24
0.08
0.01
0.31
0.54
0.15
4.03
3.39
CV(%)
14.73
2.67
8.17
5.98
4.26
2.33
0.97
4.31
7.80
5.58
17.55
12.90
R-Square
0.88
0.89
0.71
0.79
0.72
0.74
0.80
0.82
0.83
0.66
0.60
Reps 52 50
Shaded Values are not significantly different from highest value according to LSD(0.05).
† Yield and yield components for LA not included for MissStateUSDA; Yield for GA not included for WestSideCA.
‡ QS1 & QS2 = Qscore, very similar to a selection index, adds the weighted values of selected fiber traits (length, mic, UI, strength) to provide a single measure (0-100) of desirable fiber qualities, and was calculated by weighting selected fiber traits as follows: QS1 - fiber length (0.5), mic (0.25), UI (0.1), and strength (0.15) ; QS2 - fiber length (0.1), mic (0.1), UI (0.3), and strength (0.5)

10. Need for conventional cotton cultivars
Development of glyphosate-resistant weeds (Palmer amaranth)
Growers want alternatives to high tech fees (lower seed costs)
Fiber quality issues
Organic niche markets
Genetic resources for commercial breeders
MORE CHOICES for GROWERS

11. Reniform nematode in cotton
Caused by Rotylenchulus reniformis - microscopic roundworms
First reported in Georgia (Smith, 1940) and Louisiana (Smith and Taylor, 1941) as a pathogen of Gossypium hirsutum
Compound microscope view of a juvenile female reniform nematode
(Source:

12. Reniform nematode in cotton
Unobvious symptoms
Management options are limited to crop rotation and nematicides (Temik taken off market by EPA, no longer available to growers) – Resistant cultivars are not available
Losses occur primarily through a reduction in yield, boll size, and lint percentage (Cook et al., 1997)
Losses estimated at 207,000 bales in 2009 (about $70 million) (Blasingame et al., 2010)

13. Sources of Genetic resistance to RN
LONREN-1 & LONREN-2
Both derived from diploid G. longicalyx, an immune species
Single gene resistance
Gene symbol RENlon
Released in 2009 by USDA-ARS, Texas A& M AgriLife Research and Cotton Incorporated
BARBREN 713
Derived from GB 713, an accession of G. barbadense
Probably controlled by two genes
Released in 2011 by USDA-ARS, Mississippi State University, Texas A& M AgriLife Research and Cotton Incorporated

14. Yields TVREC 2010 and 2011
Reniform present
Reniform absent
Yield
Group means / Contrasts
Estimate
StdErr
Probt
Reduction
Group means
(lbs/acre)
Resistant lines (20)
905 50
1283 31
29%
Susceptible lines (20)
1115 49
1350
17%
LONREN-1 and -2
891
113
1310 59
32%
Susceptible checks
1096
1364
20%
Group mean differences
Resistant vs. susceptible lines
-210 48
0.0023
-66 24
0.0584
Resistant vs. LONREN-1 and -2 14
112
1.0000
-27 56
0.9868
Susc. lines vs. susc. checks 19
0.9998
-14
0.9987
LONREN vs. susc. checks
-205
151
0.6248
-54 76
0.9446

15. Two-year average - Lint quality
Group means
Micronaire
UHM Length
Uniformity
Fiber Strength
Elongation
Short Fiber
non-RN
Group
RN field
field
Resistant lines
4.8
1.10
84.0
32.4
32.8
5.3
4.5
7.1
7.0
Susceptible lines
4.7
4.9
1.11
83.5
83.7
30.6
31.1
5.4
7.3
LONREN-1 and -2
1.09
83.3
83.9
30.2
30.9
5.5
4.4
7.6
Susceptible checks
4.6
1.15
1.14
84.3
84.1
32.0
31.7
5.6
Significant group mean difference
Standard
Proba-
Year × Line?
Trait
Location
Error
bility
Resistant vs. susceptible lines
Nematode field
0.21
0.0000 No
Non-nematode field
0.18
Yes
0.09
0.0001
0.27
0.0697
0.0022
0.0035

16. root details
LONREN-2 no RN
LONREN ,000 RN
LONREN-2
Fibermax 966

17. Heat tolerance work
Germplasm collection screened in 2006 for heat tolerance, based on chlorophyll fluorescence following exposure to heat
More than 1700 wild accessions tested (most are photoperiodic)
Accessions identified with some level of tolerance
Crosses made between heat-tolerant accessions and adapted germplasm
F2:3 lines currently being evaluated to determine if heat tolerance is a heritable trait
Gene expression studies being conducted with these genotypes

18. Example of Appearance After Stress
TX 2287, Day 7
DPL 90, Day 7

19. Breeding for Heat Tolerance
Fig.5

20. Acknowledgments: Graduate Students Cooperating Faculty Student workers
Çidem Sürmelioğlu
Tingting Wu
Jenna May
Student workers
Caroline Land
Elliot Cantrell
Laura Beth Gulielmi
Zachary Jones
Cooperating Faculty
Dr. Kathy Lawrence
Dr. Bob Locy
Staff
Rachel Sharpe
Roelof Sikkens
Funding provided by:
Alabama Cotton Commission
Cotton Incorporated
Increase field of UA 48, 2010