Short Staple Regional Cotton Variety Trial,
Safford Agricultural Center, 1997
L.J. Clark, Safford Agricultural Center
E.W. Carpenter, Safford Agricultural Center
G.L. Hart, Maricopa Agricultural Center
J.M. Nelson, Maricopa Agricultural Cener
Twenty five short staple varieties were grown in a replicated field trial on
the Safford Agricultural Center. Yields were reduced from what was seen in 1996,
with the highest yielding variety, MAC 95 producing less than 2.5 bales per acre. It was followed closely by SG 1001, and DP 90, varieties that have been strong varieties thhroughout the 1990's. Agronomic values for the plants at harvest and HVI data for lint quality are tabulated in this paper.
This experiment is a continuation of the cotton variety testing that has taken place at this Agricultural Center since its inception and is also part of the Regional cotton testing program that takes place across the cotton belt. This test allows newer varieties, together with well tested varieties to be compared with each other and with national standards. The standards included in this test were: Maxxa, Paymaster HS26, SG 125, and Stoneville LA 887.
Materials and Methods
This replicated small plot variety trial was designed to screen a large number of cotton varieties to decide which ones should be tested further in the on-farm testing program. The plots were planted with a cone-type planter which distributes a given weight of seed uniformly over the length of the plot. The seeds were planted into a moist seed bed to promote uniform germination. The following crop history provides the information on how the crop was managed:
- Previous crop:Cotton
- Soil type: Pima clay loam variant
- Re-Planting date: 18 April 1997   Rate: 25 pounds per acre
- Herbicide: Triflurilin pre-plant, Cotton Pro at lay-by
- Fertilizer: 100 lbs/ac of urea was applied under a green manure crop 2/10, an additional 100 lbs/ac of urea was applied on 6/3 and 7/14
- Insecticide: 5 applications of insecticides to control pinkie, aphid and whitefly
- Pix/Prep: None
- Defoliation: Ginstar
- Irrigation: Furrow, pre-irrigated + 6 irrigations (ca. 24 inches + 6 inches of rain)
- Harvest dates: 1st pick: 31 October   2nd pick: Not needed
- Heat units per growing season: 3788 (86/55)
In early October 25-boll samples were collected by hand to determine boll weights. These samples were then ginned to determine percent lint turnout. The plots were picked using a modified 2-row cotton picker. The production from each plot was caught in a sack and weighed on a hanging scale to determine seed cotton yields. Sub-samples were taken to determine lint quality.
Results and Discussion
This experiment was planted near the ideal time from a long term perspective as well as for
this particular year. The cold spells of early April were avoided and adequate heat units were
available to get seed sprouted before the cool spells in May arrived. After the middle of May,
the temperature warmed up and the crop developed rapidly.
The yield data are found in Table 1 along with the plant
populations. Two SureGrow varieties were at the extremes in plant population; SG 821 had the
highest population and SG 501 had the lowest. None of the plant populations were very far
from the optimum. MAC 95, a cotton variety developed by Dr. Robert McDaniels of the University
of Arizona Plant Science Department, was the leading variety in the study with a yield of 1162
pounds of lint per acre. SG 1001 and DP 90, two well known varieties in the area followed
closely behind. It is interesting to note that DP 90 yielded 28 pounds more lint than its
transgenic counterpart, DP 35B. Two new varieties to our testing program, HYX 4103 and GC 303,
followed the DP 35B in yield. The other yield comparison will be left to the reader, depending
on the varieties of interest. A second pick was not taken since the majority of the crop was
picked in the first picking.
Table 2 contains a continuation of the agronomic data
collected. Plant heights were shorter than normal and about 5 inches shorter than seen last
year, but interestingly the number of nodes was greater. This, of course, produced smaller
height to node ratios (HNR). Plants started fruiting on average two nodes earlier than the
previous year, and the early boll load may have reduced the plant height and HNR's. Boll
weight was reduced from the previous year. A wealth of material if found in this table for
the ardent students of these particular varieties.
The HVI values in Table 3 deserve considerable study time.
Compared with last year, the average fiber was shorter, less uniform, weaker, coarser and
graded lower. Aparently the climatic conditions were not optimal for good fiber production.
- Clark, L.J., Carpenter, E.W., G.L. Hart and J.M. Nelson. 1997. Short staple cotton variety trial, Safford Agricultural Center, 1996. Cotton, A College of Agriculture Report, The University of Arizona, Tucson, AZ. Series P-108, pp. 159-164.
Appreciation is expressed to the many seed companies that contributed seed and financial assistance to make this trial a success.
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/az10063e.html
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