1997 Seed Treatment
E.R. Norton, Plant Sciences Department
J.C. Silvertooth, Plant Sciences Department
Cottonseed was treated with several fungicide treatments in an effort to protect
the seed and seedling from disease. Seed germination and vigor was evaluated in
three Arizona locations; Maricopa, Marana, and Safford. Stand counts were
taken on two separate dates after emergence at all three locations and percent
emergence (PEM) was calculated. Significant differences in percent emergence due
to treatment were observed in the both sample dates at Marana and Safford.
Maricopa showed very little significant differences due treatment.
One of the most important factors involved in producing a high yielding crop of cotton is
being able to establish a uniform and vigorous stand early in the season. There are many
factors that may affect the accomplishment of this goal. Weather is one of the most
influential factors in seedling development. Cool temperatures can slow down the germination
and growth of a cotton seedling resulting in poor seedling vigor and 'skippy' stands. Another
factor is that of seedling diseases and soil-borne fungi that can slow down growth and
development of a seedling, and in a worst case scenario, lead to the death of the seedling.
In an effort to curb the effects of seedling diseases on emergence and vigor, cottonseeds
treated with a variety of fungicides, and at different rates, were evaluated from the
standpoint of seedling emergence and viability. This project is an extension of similar
work conducted in Arizona in recent years (Silvertooth and Malcuit,1990; Silvertooth and
Malcuit, 1991; Silvertooth and Malcuit, 1992; Silvertooth and Malcuit, 1993; Norton and
Silvertooth, 1994; Norton and Silvertooth, 1995; Norton and Silvertooth, 1996, Norton and
Materials and Methods
Separate experiments were conducted at the University of Arizona
agricultural experiment stations located at Maricopa, Marana, and
Safford, AZ. Plots were planted on 13 March at Maricopa, 28 March at Marana,
and 8 April at Safford. Heat units accumulated since 1 January were 312, 469,
and 441 heat units accumulated since 1 January (86/55° F thresholds) for
Maricopa, Marana, and Safford respectively. Experiments were arranged in a
randomized complete block design with each of the 8 treatments (Table 1) being
replicated four times. Plots consisted of four, 40" rows that extended 40'
in length. Exactly 200 seeds were planted in each of the four rows for every
experimental unit. Percent emergence (PEM) was calculated for two sampling dates
at each location based upon number of emerged, viable seedlings as a percentage
of 200 seeds planted. Percent emergence values obtained were subjected to
analysis of variance according to guidelines put forth in Gomez and Gomez (1984)
and the SAS institute (1988). Due to missing values, the data set obtained was
unbalanced. The general linear models (GLM) statement was used for analysis of
variance along with a pairwise comparison t-test using least square means data
for a given two treatment comparison. The resultant observed significance level
from the t-test was used to determine if the differences between any two given
treatments was significant. Differences were declared significant at the
Results obtained at the Maricopa location are consistent with previous years of studies
conducted. Analysis of variance on the overall data revealed no significant differences among
treatments. Table 2 lists the treatments and in descending
order of PEM for both sample dates. Similar trends were observed between the two sample
dates (8 April and 25 April). Significant differences among treatments were found only
between treatment 8 (control) and the treatment with the highest PEM, treatment 6
(Table 1). All other differences among treatments were not
statistically significant. Soil temperature data for the study is found in
Figure 1. Mean soil temperatures at a depth of
2.5 in. were at
or above 65°C for approximately 20 days post planting. This resulted in near optimum
conditions for seedling emergence. A sharp decrease in soil temperatures did occur after
this 20 day period but seedlings were well established and were not adversely affected by the
brief decrease in soil temperatures.
Results at the Marana Agricultural center were once gain consistent with past year's
studies. Planting conditions were conducive to producing significant results.
Figure 2 indicates that the mean soil temperatures for
approximately the first 20 days after planting were at or below 65° C with a
below 60° C at approximately 6 days after planting.
Treatment listings for PEM are found in
Table 3. Significant results were found among several
treatment comparisons for the second sample date (30 May). Treatment 8 (control) was
significantly lower than all other treatments. Treatments 3 and 6 were significantly higher
than two of the other treatments including; 1 and 2. All other treatments were not
Mean soil temperatures at the Safford Agricultural Center near the date of planting were
well below the optimum of 65° C (Figure 3). Two days prior to
planting temperatures dropped below 60° C to approximately 55° C.
Mean soil temperatures
remained below optimum for approximately the first 15 days post planting.
Table 4 outlines results of PEM for each of the 8 treatments.
All treatments were significantly higher than the control (treatment 8). Treatment 4, which
had the highest PEM, was significantly higher than treatments 1, 2, and 7 as well. Treatments
3 and 5 were also significantly higher than 1, 2, and 7 but not statistically different
than treatment 4.
At all locations, the benefit of planting chemically treated seeds is clearly demonstrated.
Different treatment combinations also performed differently across the three locations.
Treatment 6 performed well at both Maricopa and Marana but not so well at Safford while
treatment 4 performed well at Safford but not at Maricopa and Marana. Another important
consideration from these studies is that the overall PEM never exceeded 60%. It is common
to use an estimate of 80% emergence when making decisions on seeding rates at planting.
The evidence presented in this study indicates a more conservative estimate may be
The authors gratefully acknowledge the support provided by the Wilbur-Ellis Co., and also the valuable assistance provided by the very capable personnel at the Maricopa, Marana, and Safford Agricultural Centers of the University of Arizona, and the student research assistants with the cotton agronomy research program at the University of Arizona.
- Gomez, K.A. and A.A. Gomez. 1984. Statistical Procedures for Agricultural Research, Inc. Ed. John Wiley and
Sons, Inc. p. 307.
- SAS Institute. 1988. SAS/STAT: Procedures. Release 6.03 ed. SAS Inst., Cary, NC.
- Silvertooth, J.C. and J.E. Malcuit. 1990. Cottonseed treatment evaluations in Arizona, 1989. Cotton, A College of
Agriculture Report. University of Arizona, Series P-81:129-133.
- Silvertooth, J.C. and J.E. Malcuit. 1991. Cottonseed treatment evaluations in Arizona, 1990. Cotton, A College of
Agriculture Report. University of Arizona, Series P-87:233-240.
- Silvertooth, J.C. and J.E. Malcuit. 1992. Cottonseed treatment evaluations in Arizona, 1991. Cotton, A College of
Agriculture Report. University of Arizona, Series P-91:221-227.
- Silvertooth, J.C. and J.E. Malcuit. 1993. Cottonseed treatment evaluations in Arizona, 1992. Cotton, A College of
Agriculture Report. University of Arizona, Series P-94:356-361.
- Silvertooth, J.C. and E.R. Norton. 1994. Cottonseed treatment evaluations in Arizona, 1993. Cotton, A College of Agriculture Report. University of Arizona, Series P-96:419-424.
- Norton E.R. and J.C. Silvertooth 1995. 1994 Cottonseed treatment evaluations. Cotton, A College of Agriculture Report. University of Arizona, Series P-99:355-360.
- Norton E.R. and J.C. Silvertooth 1996. 1995 Cottonseed treatment evaluations. Cotton, A College of Agriculture Report. University of Arizona, Series P-103:365-371.
- Norton E.R. and J.C. Silvertooth 1997. 1996 Cottonseed treatment evaluations. Cotton, A College of Agriculture Report. University of Arizona, Series P-108:425-432.
This is a part of publication AZ1006:
"Cotton: A College of Agriculture Report," 1998, College of Agriculture, The University of
Arizona, Tucson,Arizona, 85721.
Any products, services, or organizations that are mentioned, shown, or indirectly
implied in this publication do not imply endorsement by The University of Arizona.
The University is an Equal Opportunity/Affirmative Action Employer.
This document located at http://ag.arizona.edu/pubs/crops/az1006/az10069a.html
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