Arizona Upland Cotton Variety Testing Program, 1997

J. Silvertooth, Plant Sciences Department
R. Norton, Plant Sciences Department
L. Clark, Safford Agricultural Center
S. Husman, Pinal County Cooperative Extension
T. Knowles, La Paz County Cooperative Extension
R. Gibson, Pinal County Cooperative Extension


Eleven field experiments were conducted in major cotton growing areas of Arizona in 1997 for the purpose of evaluating Upland cotton varieties in terms of adaptability and performance. Six commercial cottonseed companies participated in the program. A maximum of two varieties were submitted by each company at each location. Experiments were conducted on a commercial level on grower-cooperator fields in most cases. Locations used in the program spanned the range of conditions common to cotton producing areas of the state from about 100 ft. to 4,000 ft. elevation. Results indicated a broad range of adaptability and competitiveness. Each of the participating seed companies offer a compliment of varieties that can serve to match various production strategies commonly employed in the state. Many varieties commercially available performed well at several locations demonstrating good adaptation to Arizona conditions.


Cotton farmers in Arizona are always very interested in the performance of new and established varieties. Growers are also interested in the adaptability and performance of varieties in their area. Not only is there an interest on the part of farmers regarding objective, unbiased data describing cotton varieties, but the commercial seed companies are also motivated to support the development and operation of an independently based variety testing program for the state of Arizona. A statewide Upland variety testing program was conducted in 1997 involving the University of Arizona Cooperative Extension System, farmer-cooperators in eight counties, and six commercial cottonseed companies. The objective of the project is test commercially available varieties under commercial conditions at several representative cotton-growing locations in Arizona. Variety evaluation is conducted in terms of growth and development patterns, yield, and quality.


An Upland variety testing program was conducted at eleven locations in 1997 (Yuma Valley, Parker Valley, Mohave Valley, Buckeye, Gila Bend, East Valley - Maricopa County, Maricopa, Coolidge, Marana, Sulfur Springs Valley, and Safford), involving six commercial cottonseed companies (Delta Pine, Stoneville, Sure-Grow , J&S Research, Paymaster-Hartz, and AgriPro). At each location, each participating company submitted a maximum of two varieties, for a total of 11 varieties per location. Most tests were conducted on grower-cooperator fields, with plots (individual varieties) being a minimum of four rows wide (38 to 40 inch spacings), and extending the full length of the irrigation run. All treatments (varieties) were arranged in a randomized complete block design with four replications in each case. Yield estimates were made by harvesting a minimum of the entire two, centermost rows, of each plot. Resulting seedcotton weights were obtained from each plot by the use of electronic scales placed at the end of the field. Subsamples of seedcotton were ginned for turnout estimates, and lint samples were subjected to HVI analysis. All data was analyzed statistically in a manner consistent with the experimental design by use of analysis of variance methods (Steel and Torrie, 1980), and procedures outlined by the SAS Institute (SAS, 1988).


Yield analyses revealed significant effects associated with location, which is not at all surprising given the wide range in environmental conditions experienced among locations (Tables 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11). Elevation differences ranged from approximately 100 to 4,000 ft. above sea level. Ranges in dates of planting, in relation to optimal dates for each location, and insect infestations also contributed to location and regional differences.

Results are representative of the variety performances among the locations utilized and of the growing season experienced in 1997. There are several points that are worthy of noting with respect to the 1997 results:

  • In general, the Bt varieties performed very well in relation to the other varieties at each location. In all cases, complete measures were taken to accomplish pink bollworm (Pectinophora gossypiella (Saunders)) control. However, differences in the yield of Bt varieties in comparison to similar varieties or their recurrent (non-transgenic) parents, appeared to be due to differences in insect (pink bollworm) damage and not due to agronomic differences. These results are consistent with those provided from a study conducted in 1996 comparing new transgenic varieties with their recurrent parents (Silvertooth et al., 1997) and a similar project conducted in 1997.

  • Several non-transgenic varieties yielded very well among locations in 1997. For example, STV 474 generally performed very well in 1997 at many locations. This variety has also demonstrated good yielding potential in this project over the past several years. This type of demonstration of consistency in performance is important to consider in variety selection. With regard to STV 474 it is also interesting to note that it is a hairy leaf variety, and therefore, it tends to attract whiteflies (Bemisia tabaci (Gennadius)) a little sooner than other smooth leaf varieties. However, the insect growth regulators (IGRs) used for whitefly control have been very effective, which serves to make the use of varieties like STV 474 quite feasible. STV 474 may be a good candidate to use as Bt refugia, particularly in a short season production system where it may be able to avoid (by early fruit set) peak periods of whitefly an and pink bollworm activity.


Cotton breeders, farmers, and agronomists are constantly in the process of critiquing and reviewing conventional varieties with respect to possible improvements. Regional adaptability of varieties is a factor of interest to any cotton-producing region, Arizona being no exception. The companies and varieties under review in this program are the products of rather intense screening and evaluation under Arizona conditions. This project illustrates hat there are a number of good varieties for many locations and conditions in Arizona given proper placement and management.


The valuable cooperation, land, and resources provided by Ft. Mohave Avi Kwa 'Ami Farms, Colorado River Indian Tribes Farms, H-Four Farms, J.S. Stephens and Sons, Smith Farms, University of Arizona Yuma Valley Agricultural Center, Marvin Wuertz Farms, University of Arizona Marana Agricultural Center, Carpenter Farms, and Ed Curry Farms is highly appreciated. The support and cooperation provided by the participating companies in this project (Deltapine, Stoneville, SureGrow, Paymaster-Hartz, and J&S Research and AgriPro seed companies) is gratefully acknowledged.


  1. SAS Institute. 1988. SAS/STAT:Procedures. Release 6.03 ed. SAS Inst., Cary, NC.
  2. Silvertooth, J.C., E.R. Norton, S.H. Husman, T. Knowles, and D. Howell. 1997. Agronomic evaluations of transgenic Bt cotton varieties in Arizona. Cotton, A College of Agriculture Report. University of Arizona. (this issue).
  3. Steel, R.G.D., and J.H. Torrie. 1980. Principles and procedures of statistics. McGraw-Hill, New York.

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.
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