COTTON VARIETY ASSESSMENT FOR FIBER MATURITY
G.H. Davidonis, USDA Southern Regional Research Center, davidon@srrc.ars.usda.gov
J.I. Dickson, LSU AgCenter, Dep. of Agronomy and Environmental Management
D. J. Boquet, LSU AgCenter, Macon Ridge Research Station
Each year, scientists with the LSU AgCenter test cotton varieties at various locations throughout
the state. Varieties are grown using practices that follow AgCenter recommendations and
conform to commercial operations as closely as possible. One location is the Macon Ridge
Research Station in Winnsboro where cotton is grown on non-irrigated and irrigated Gigger silt
loam. Cotton Variety Tests were planted in a randomized complete block design. The irrigated
trials had four blocks and the non –irrigated trials had three blocks. Prior to 2004, 50-boll
samples were hand harvested. In 2004, samples for fiber analysis were harvested with a two-row
mechanical harvester. Cotton was ginned on a laboratory saw gin. Fiber quality was determined
by the Louisiana Agricultural Experiment Station Cotton Fiber Testing Laboratory using HVI
(High Volume Instrumentation) equipment and at the USDA Southern Regional Research Center
using HVI and AFIS (Advanced Fiber Information System). A highly discriminating location is
one that maximizes the observed varietal differences among cottons. Winnsboro has been
designated as a discriminating environment for yield and fiber length (Blanche and Myers,
2006).
High micronaire has been a problem in Louisiana in recent years. Because seed company product
guides often present averages for fiber properties, careful consideration of cotton variety trials
can help producers identify types of varieties that have the potential to be discounted on
micronaire. Identifying fiber maturity properties that fit a specific profile will assist breeders in
the selection of low micronaire cottons. The HVI fiber properties include Upper Half Mean
length and micronaire. Perimeter and fiber cell wall thickness were calculated from the AFIS
Maturity Ratio and Fineness values. Micronaire is a composite of fineness and maturity. The
basic fiber constituents are perimeter and cell wall thickness and provide cotton breeders
valuable information.
All varieties listed in Table 1 were designated as being long (UHM 1.11 – 1.26in) under irrigated
conditions in 2004. Under non-irrigated conditions only nine varieties retain that designation.
The varieties were arranged in order of ascending perimeter. When the same variety was
compared across several environments a range of perimeters was obtained. This range was about
2 micrometers. The larger perimeter PHY410 R with a micronaire of 5.0 had a thinner cell wall
than FM966 LL. Therefore, at the same micronaire FM966 LL was more mature than PHY410
R. Both small and large perimeter varieties had the potential to have micronaire values above
4.9.
The UHM and micronaire values from non-irrigated and irrigated (2004) varieties were plotted
together (Fig.1). As fiber length increased micronaire decreased. Irrigation has the potential to
reduce micronaire values. Also, irrigation can increase micronaire values. In 2003, irrigation did
not increase fiber length in most varieties (Table 2). Two varieties showed an increase in length
but no increase in micronaire. Six varieties showed at least a 0.5 micronaire increase with
irrigation.
SELECTION OF LOW MICRONAIRE VARIETIES
Lower micronaire varieties are characterized by small perimeter, long fiber or reduced cell wall
thickness. Small perimeter varieties are a good choice. In the 2001 Winnsboro Non-Irrigated
Variety Trials the mean micronaire for 18 medium maturing varieties was 5.5 but the micronaire
for FM832 was 5.2. In the 2004 Winnsboro Non-Irrigated Variety Trials the mean micronaire
for 21 medium maturing varieties was 5.1 but the micronaire for FM832 LL was 4.4. An
examination of Winnsboro Irrigated Variety Trial data from 2004 and 2005 revealed that longer
fiber varieties tended to have lower micronaire values. In 2004 there were 11 varieties with
UHM lengths at or below 1.14 in. with a mean micronaire of 4.6 while 9 varieties had a UHM of
1.20 in. and above with a mean micronaire of 4.2. In 2005 there were 9 varieties with mean
UHM lengths at or below 1.08 in. with a mean micronaire of 4.5 while 6 varieties had a UHM
of 1.14 in. and above with a mean micronaire of 4.2.
Reduced cell wall deposition is another means to achieve lower micronaire. This can be
accomplished if the rate or duration of cell wall deposition changes. Fiber lengths for FM966 LL,
FM960 B/R, DP444 B/R and DP555 B/R were not significantly different under irrigated
conditions in 2004. Cell wall thicknesses were 2.7, 2.7, 2.8 and 2.7 micrometers, respectively.
Under non-irrigated conditions in 2004 fiber lengths were shorter and micronaire increased. Cell
wall thickness for DP444 B/R was significantly thinner than the other three varieties (Table 1).
In 2003, non-irrigated fiber lengths for FM966, DP444 B/R and DP555 B/R were not
significantly different. Cell wall thicknesses were 2.5, 2.6, and 2.6 micrometers, respectively.
Cell wall thickness for FM966 was significantly different from the other two varieties. Under
irrigation fiber lengths were not significantly different (Table 2). Cell wall thickness for FM966,
DP444 B/R and DP555 B/R were 2.7, 2.5 and 2.6 micrometers, respectively. Cell wall thickness
for DP444 B/R was significantly different from the other two varieties. Although PHY410 R had
the same cell wall thickness as DP444 B/R, the large perimeter contributed to a micronaire of 5.0
( Table 1). In order to identify varieties with reduced cell wall deposition in high micronaire
environments it is necessary to test them in high micronaire environments.
Prior to variety release, selections can be made in environments where micronaire values are
below 4.9. Fiber perimeter and cell wall thickness can be determined and compared to test
varieties grown at the same location. Varieties suitable for test cottons can be obtained from
Table 1. A range of perimeters can be obtained if FM800 B/R, DP488 B/R and PHY 410 R are
selected. For example in 2004, variety T57 was grown under irrigated conditions and had a
micronaire of 4.4. The perimeters for FM800 B/R, DP488 B/R and PHY410 R were 47.3, 51.1
and 53.0 micrometers, respectively. Cell wall thicknesses were 2.4, 2.7 and 2.7 micrometers,
respectively. The perimeter for T57 was 52.3 micrometers and cell wall thickness was 2.6
micrometers. Since fiber length of T57 was not significantly different from PHY410 R it would
be expected that T57 under high micronaire conditions would have a micronaire above 4.9.
CONCLUSIONS
Selection of varieties with HVI micronaire values below 4.5 depends on consideration of variety
trial data supplemented with AFIS fiber perimeter and wall thickness data.
REFERENCES
Variety Trial information is available at:
lsuagcenter.com/en/communications/publications/Publications+Catalog/Crops+and+Livestock/C
otton/Cotton+Varieties+for+Louisiana.htm
Blanche, S.B., and G.O.Myers.2006. Identifying discriminating locations for cultivar selection in
Louisiana. Crop Sci. 46:946-949.
Table 1. Perimeter, length and maturity properties of 20 cotton varieties grown
under non-irrigated conditions at the Macon Ridge Research Station in 2004
(Winnsboro, LA).
Cell Wall
Variety
Perimeter
UHM
Micronaire
Thickness
µm
in.
µm
FM 800 B/R
50.9f*
1.15ab
4.7d
2.8cd
FM 800 B2R
50.0g
1.17a
4.8bcd
2.8bc
FM 966 LL
50.8f
1.09de
5.0bc
2.8c
BCG 295
52.1de
1.15ab
4.7cd
2.9ab
FM 960 B/R
DP 494 R
DP 543 B2R
ST 6636 B/R
DP 493
DP 444 B/R
DP 488 B/R
DP 555 B/R
ST 5599 B/R
51.6de
52.0de
52.5cd
52.7b
53.1 b
51.7e
52.5cd
52.5cd
52.9b
1.078e
1.11cd
1.09de
1.12cd
1.12bc
1.10de
1.14abc
1.08de
1.09de
5.2a
4.8bcd
5.2a
5.3a
5.2a
4.6d
5.0bc
5.2a
5.0bc
2.8bc
2.8bc
2.9ab
3.0a
2.9ab
2.7d
2.9bc
2.9ab
2.9ab
DP 393
DP 434 R
ST 3636 B2R
ST 4575 B/R
ST 5454 B/R
PHY 410 R
DP 424 B2R
52.9bc
53.1b
53.2b
53.2b
54.0a
53.0b
54.3a
1.13bc
1.12bc
1.09de
1.08de
1.08de
1.09de
1.08e
5.0ab
5.1a
4.9bc
5.1a
5.2a
5.0bc
5.1a
2.8bc
2.9b
2.9bc
2.9bc
3.0a
2.7d
2.8bc
*Means followed by the same letter within a column are not statistically different at the
0.05 probability level.
Table 2. Length and micronaire for cotton grown under non-irrigated and irrigated
conditions at the Macon Ridge Research Station in 2003 (Winnsboro,
LA)
UHM (in.)
Variety
FM 800 B/R
FM 966
BCG 295
FM 960 B/R
FM 958
DP 491
DP 494 R
DP 493
DP 444 B/R
DP 555 B/R
PHY 510 R
DP 5599 B/R
PHY410R
ST 4563 B2
DP 424 B2R
Rainfed
1.16a*
1.09a
1.13a
1.04a
1.07b
1.15a
1.13a
1.07b
1.10a
1.08a
1.13a
1.04b
1.05a
1.10a
1.11a
Irrigated
1.19a
1.10a
1.15a
1.07a
1.13a
1.19a
1.13a
1.12a
1.08a
1.09a
1.12a
1.11a
1.09a
1.09a
1.07a
Micronaire
Rainfed
Irrigated
4.1A
4.0A
3.9B
4.7A
4.1B
4.5A
3.8B
4.7A
4.4B
4.9A
4.2B
4.6A
4.3B
4.6A
4.6A
4.6A
3.8B
4.1A
4.4B
4.8A
4.4A
4.8A
4.8A
4.9A
4.1B
4.7A
3.8B
4.8A
3.8B
4.7A
*Means followed by the same lower case letter within a row are not statistically different
and means followed by the same upper case letter are not statistically different at the 0.05
probability level.
5.5
Micronaire
5
4.5
4
R2 = 0.7328
3.5
3
1.06
1.08
1.1
1.12
1.14
1.16
1.18
1.2
1.22
UHM (in.)
Figure 1. Relationship between micronaire and UHM for varieties
grown under non-irrigated and irrigated conditions in 2004.
1.24