Short Staple Variety Trials, Graham County, 1997

Abstract

Two on-farm, replicated short staple variety demonstrations were planted in 1997. Twelve varieties were evaluated on the Carpenter farm in Central and on the Colvin farm in Eden. Several new varieties were planted in both studies, including 2 transgenic varieties, DP 35B and BXN 47, 2 varieties from Australia and four other varieties seen for the first time. DP 35B and Stoneville 474 were the highest yielding varieties in Central and the Australian variety, IF 1003, had the highest yield in Eden with yields over 2 bales per acre. Other agronomic data from the varieties and HVI values from the lint are also included in this report.

Introduction

This cotton variety trial, similar to the previous year's studies, is part of state-wide variety evaluation done in conjunction with Dr. Jeff Silvertooth and six seed companies. But, even more important, is part of the on-going variety trials conducted in the county for the benefit of local cotton growers.

Materials and Methods

The demonstrations were grown with the cooperation of Darin Carpenter in Central, at an elevation of 2900 feet, and Colvin Farms in Eden, at an elevation of 2800 feet, using their equipment and normal cultural practices. The two sites differ in elevation by about 100 feet with the Carpenter field being higher and generally warmer. The varieties were planted in 2-row plots in four replications at the Carpenter site and 4-row plots with three replicates on the Colvin site. Plots were mechanically picked using the cooperator's machines, with each plot being weighed separately using electronic weigh scales under cotton trailers. Sub-samples were taken to determine lint turnout and fiber quality.

Crop History - Carpenter farm

Previous crop:

Soil type: Pima clay loam variant

Previous crop: Cotton

Planting date: 17 April 1997         Rate: 26 pounds per acre

Fertilizer: 30 gallons of 20-10-0 side dressed late May

Herbicide: None

Insecticide:

Irrigation: Furrow, 7 times

Defoliation: Sodium chlorate

Harvest dates: 1st Pick: 29 October         2nd Pick: Not taken

Heat units (86/55) to 1st pick: 3786

Crop History - Colvin farm

Previous crop: Cotton

Soil type: Grabe clay loam

Planting date: 2 May 1997         Rate: 20 pounds per acre

Fertilizer: 40 pounds of N water run

Herbicide: Treflan and caparol incorporated pre-plant

Insecticide: None

Defoliation: Sodium chlorate

Irrigation: Furrow

Harvest dates: 1st Pick: 17 November         2nd Pick: Not taken

Heat units (86/55) to 1st pick (recorded at Safford Ag Center): 3702

Results and Discussion

The weather plays a significant part in the yield of cotton and also which variety does best in what location. The months of April and May are pivotal to stand establishment. The total number of heat units received in 1997 was very comparable to those received in 1996 (1, 2) and temperatures were normal (compared to a 30 year average up to the end of March (3). From the second week in April to the middle of May heat units were 1 to 2 days behind normal and it was observed that stand establishment was delayed especially west of Pima. Beginning the middle of May, the temperatures rose and the heat units ran ahead of normal.

Tables 1a and 1b show the yield and other agronomic data from the Carpenter trial. Yields were considerably lower than the previous year and only two varieties yielded over 2 bales per acre. DP 35B, the transgenic version of DP 5690, produced the highest yield with Stoneville 474 very close behind.

HVI analyses on the subsamples taken from the Carpenter field are listed in Table 3a. Grades were very good even though most HVI values were not as good as the previous year. HS 12 and HS 22, two of the new varieties being tested had the longest fiber with length reaching 1.17 to 1.18 inches

The results of the Colvin trial are found in Tables 2a and 2b. The Australian variety, IF 1003, was the highest yielding variety in the trial. This variety was the highest yielding non-transgenic variety in the short stapleadvanced strains trial (4) as well as in thehighest yielding Australian variety in last year's advanced strains trial (5). The new variety HYX 4103 and DP 35B were next in line for yield.

Boll samples were taken from first position locations in the center of plants to determine an average boll weight.

The HVI results from the Colvin trial are found in Table 3b. The average quality of fiber was worse than last year. The longest fiber came from HS 12, but the average fiber length was higher than that of DP 90.

References

1. Brown, P. AZMET weather system. The University of Arizona.
2. Clark, L.J. and R.E. Cluff. 1997. Short staple variety demonstrations, Graham county, 1996. Cotton, A College of Agriculture Report, The University of Arizona, Tucson, AZ. Series P-108, pp. 149-154.
3. Brown, P. et.al. 1998. 1997 Cotton advisories. http://ag.arizona.edu/azmet/data/0497cot.txt
4. Clark, L.J. and E.W. Carpenter. 1998. Short Staple Cotton Advanced Strains Trial, Safford Agricultural Center, 1997. In this publication.
5. Clark, L.J. and E.W. Carpenter. 1997. Short Staple Cotton Advanced Strains Trial, Safford Agricultural Center, 1996. Cotton, A College of Agriculture Report, The University of Arizona, Tucson, AZ. Series P-108, pp.134-138.