Progress 10/01/05 to 09/30/09
Outputs
OUTPUTS: Four separate research projects were completed during the lifetime of the project. The first was a study that used six family groups of upland cotton, derived by backcrossing, to measure the degree and rate of recovery of traits from the cotton variety being improved. Each group consisted of a different nonrecurrent parent (NRP); a cultivar from Africa with resistance to bacterial blight; the same recurrent parent (RP); a fourth generation of the cross between them; and four backcross generations. All entries were evaluated for lint yield, six fiber properties, and seven agronomic characters. Reactions to three diseases were also determined. The second study compared sixty-one upland cotton varieties for their reactions to Race 1 and to a mixture of virulent races of the organism causing bacterial blight. The third project was an historical evaluation of a self-taught plant breeder from Oklahoma who worked with unusual cotton plants and other crops in the late 1920s to 1950s. The final experiment was conducted to determine the effects of partial or complete loss of cotyledons due to an array of causes in the early vegetative cotyledon stage on lint yield, selected lint yield components, and fiber traits. Results from the four studies have been published. PARTICIPANTS: L.M. Verhalen retired effective June 2, 2008. M.B. Bayles assumed the role of Project Leader at that time. Participants over the life of the project have included L.M. Verhalen, M.B. Bayles, M.R. Albers-Nelson, B.E. Greenhagen, and B.R. Barnes. TARGET AUDIENCES: Results from this research are targeted toward cotton producers, plant breeders, researchers, extension personnel, and crop insurance adjustors. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The major outcome of this project was a change in knowledge. In the first study, it was found that three, four, or often more backcrosses were required to recover the RP traits. The number of backcrosses required depended upon the trait in question. Several instances of transgressive segregation were noted mainly in the earlier backcross generations. This suggests that breeders using this method should probably screen their materials in earlier generations than is the norm. The observed rate of recovery of RP traits was 96% of the theoretical rate. The knowledge generated from this study should make future use of the backcrossing method more efficient. In the second study, significant differences in blight reactions were detected among varieties for both Race 1 and the race mixture. Mean reactions among varieties ranged from immune to fully susceptible. Varieties included in this study were developed in seven states. The only varieties among them with resistance or immunity to the array of races used for screening in this study were from Texas and Oklahoma. Varieties developed elsewhere were moderately to fully susceptible. Large areas of the Cotton Belt remain vulnerable to outbreaks of bacterial blight unless higher levels of resistance are more widely incorporated into breeding programs than have been in the past. This research pinpoints sources of genetic resistance to bacterial blight which, if utilized, could prevent yield reductions of up to 50 % (or more) in future U.S. cotton. The third study explored the breeding efforts of J.A. Webb, a tenant farmer near Union City, OK who worked for more than 30 years to improve cotton and other plants. This paper outlined both his successes and his failures. Those who do not study the past are less likely to repeat its successes and are more likely to repeat its failures. In the fourth study, it was found that loss of half a cotyledon apparently stimulated the cotton plant to overcompensate for lint yield by 4 to 6%. The plant compensated for the loss of up to one cotyledon in all traits except fiber strength in one year. Loss of one and one-half cotyledons reduced lint yield (11-33%), picked lint percentage (up to 2.1%), pulled lint percentage ().4%), micronaire (up to 0.2 units), and fiber elongation (up to 0.3%). Loss of both cotyledons reduced lint yield (81-100%), picked lint percentage (up to 4.6%), pulled lint percentage (4.7%), boll size (0.85 g per boll), micronaire (up to 1.6 units), and fiber elongation (up to 1.4%). Fiber length and length uniformity were not affected by cotyledon removal. Fiber strength exhibited significant differences in one experiment, but no trend. The elimination of both cotyledons when the first true leaf was about the size of a dime was considerably less harmful to the plant than when done earlier in the season. The information derived from this research should enable cotton producers to make better decisions regarding whether to replant or not following crop injury. It should also enable crop insurance adjustors to make more equitable settlements with clients whose cotton has been damaged.
Publications
- No publications reported this period
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Seedlings of upland cotton are vulnerable to the partial or complete loss of their cotyledons due to an array of causes. Experiments were conducted to determine the effects of such losses in the early vegetative cotyledon growth stage on lint yield, selected lint yield components, and fiber traits. PARTICIPANTS: L.M. Verhalen M.B. Bayles TARGET AUDIENCES: Results from this research should help cotton producers, crop insurance adjustors, researchers, and extension personnel make better decisions about cotton following crop injury. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Loss of half a cotyledon apparently stimulated the cotton plant to overcompensate for lint yield by 4 to 6%. Overcompensation was not detected for lint yield components or fiber traits. The plant compensated for the loss of up to one cotyledon in all traits except fiber strength in one year. Loss of one and one-half cotyledons reduced lint yield (11-33%), picked lint percentage (up to 2.1%), pulled lint percentage ().4%), micronaire (up to 0.2 units), and fiber elongation (up to 0.3%). Loss of both cotyledons reduced lint yield (81-100%), picked lint percentage (up to 4.6%), pulled lint percentage (4.7%), boll size (0.85 g per boll), micronaire (up to 1.6 units), and fiber elongation (up to 1.4%). Fiber length and length uniformity were not affected by cotyledon removal. Fiber strength exhibited significant differences in one experiment, but no trend. The elimination of both cotyledons when the first true leaf was about the size of a dime was considerably less harmful to the plant than when done earlier in the season. The information derived from this research should enable cotton producers to make better decisions regarding whether to replant or not following crop injury. It should also enable crop insurance adjustors to make more equitable settlements with clients whose cotton has been damaged.
Publications
- Verhalen, L.M., Bayles, M.B., and Greenhagen, B.E. 2008. Cotyledons in upland cotton: How important are they Crop Sci. 48:1967-1974.
- Verhalen, L.M., Bayles, M.B., and Greenhagen, B.E. 2008. Cutups in the cotton patch. p. 835 in Proc. Beltwide Cotton Conf. Natl. Cotton Counc., Memphis, TN.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: J.A. Webb, a tenant farmer near Union City, OK, discovered an unusual cotton plant in one of his fields in 1928. The plant had red leaf color, bolls set in clusters, high fiber quality, and boll weevil nonpreference. This paper explores Webb's subsequent breeding efforts over 30 years with that (and other) cotton and with other plants in Oklahoma. For someone with fewer than 5 years of education, Webb accomplished a great deal; but he made his share of mistakes as well. He was truly a "self-made" man. He had big dreams. He fell somewhat short in achieving those dreams. But then, don't we all? The results of the next two references were reported in last year's annual report. The last reference summarized our preliminary findings on the importance of cotyledons in the early VC growth stage on cotton lint yield, selected lint yield components, and fiber traits. A journal article with a more detailed analysis is being reviewed at this time.
PARTICIPANTS: L. M. Verhalen M. B. Bayles M. R. Albers-Nelson B. E. Greenhagen
TARGET AUDIENCES: Cotton Producers, Plant Breeders, Researchers, Extension Personnel
Impacts
Ref. no. 1: Those who do not study the past are less likely to repeat its successes and are more likely to repeat its failures. Ref. no. 2 and 3: This research pinpoints sources of genetic resistance to bacterial blight in cotton which, if utilized, could prevent yield reductions of up to 50% (or more) in the U.S. cotton of the future. Ref. no. 4: The information derived from this research should enable cotton producers to make better decisions whether to replant or not following crop injury.
Publications
- ALBERS-NELSON, M.R., and VERHALEN, L.M. 2006-07. J.A. Webb, early-day cotton breeder from Union City, Oklahoma. Chron. Okla. 84:464-491.
- BAYLES, M.B., and VERHALEN, L.M. 2007. Bacterial blight reactions of sixty-one upland cotton cultivars. J. Cotton Sci. 11:40-51.
- BAYLES, M.B., and VERHALEN, L.M. 2007. Bacterial blight reactions of 61 upland cotton cultivars. p. 197-202. In Proc. Beltwide Cotton Conf., New Orleans, LA. 9-12 Jan. 2007. Natl. Cotton Counc. Am., Memphis, TN.
- VERHALEN, L.M., BAYLES, M.B., and GREENHAGEN, B.E. 2007. Cotyledons in cotton: Who needs em? p. 221-222. In Proc. Beltwide Cotton Conf., New Orleans, LA. 9-12 Jan. 2007. Natl. Cotton Counc. Am., Memphis, TN.
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Progress 10/01/05 to 09/30/06
Outputs
Sixty-one upland cotton varieties were compared for their reactions to Race 1 and to a mixture of virulent races of the organism causing bacterial blight. Varying numbers of varieties (including four checks) were planted in replicated experiments each year near Perkins, OK, over a 3-year period. Significant differences in blight reactions were detected among varieties each year for both Race 1 and the race mixture. Mean reactions among varieties ranged from immune to fully susceptible. Varieties included in this study were developed in seven states. The only varieties among them with resistance or immunity to the array of races used for screening in this study were from Texas and Oklahoma. Varieties developed elsewhere were moderately to fully susceptible. Large areas of the Cotton Belt remain vulnerable to outbreaks of bacterial blight unless higher levels of resistance are more widely incorporated into breeding programs than have been in the past. This research is
currently in press at the Journal of Cotton Science.
Impacts
Bacterial blight can be a serious disease in most upland cotton growing areas of the world. While blight outbreaks in the U.S. are infrequent, serious epidemics can occur wherever susceptible varieties are grown. This research pinpoints sources of genetic resistance to that disease which, if utilized, could prevent yield reductions of up to 50% (or more) in future U.S. cotton.
Publications
- BAYLES, M.B., VERHALEN, L.M., McCALL, L.L., JOHNSON, W.M., and BARNES, B.R. 2006. Recovery of recurrent parent traits when backcrossing in cotton. p. 881. In Proc. Beltwide Cotton Conf., San Antonio, TX. 3-6 Jan. 2006. Natl. Cotton Counc. Am., Memphis, TN.
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Progress 10/01/04 to 09/30/05
Outputs
Six family groups of upland cotton, derived by backcrossing, were compared over multiple environments. Each group consisted of a different nonrecurrent parent (NRP), a cultivar from Africa with resistance to bacterial blight; the same recurrent parent (RP), Westburn 70, susceptible to that disease; the F4 of the cross between them; and the Bc1F4, Bc2F4, Bc3F4, and Bc4F4 generations. All entries were evaluated for lint yield, six fiber properties, and seven agronomic characters. Reactions to three diseases were also determined for the Bc4F4 and the RP in two environments per disease. The objectives of this study were to measure the degree and rate of recovery of RP traits through four backcross generations in upland cotton as well as to determine reactions to three diseases (including blight) in the Bc4F4 generation. Eighty-four sets of comparisons (six family groups by 14 traits) were possible in the portions of the study not involving diseases. The NRPs differed
significantly from the RP in 69 of the 84. Among those 69 combinations, the number (and percentage) of significant differences from the RP in the F4, Bc1F4, Bc2F4, Bc3F4, and Bc4F4 were 47 (68%), 35 (51%), 25 (36%), 25 (36%), and 14 (20%), respectively. No significant differences were detected in any family group between the Bc4F4 and the RP for lint yield, 2.5 and 50% span lengths, uniformity index, and pulled lint percentage. One or more such differences were found for micronaire, T0 and T1 fiber strengths, picked lint percentage, boll size, bur size, lint weight per boll, lint index, and seed index. Depending upon the trait, three, four, and often more backcrosses were required to recover the RP traits. Several instances of transgressive segregation were noted mainly in the earlier backcross generations. The observed rate of recovery of RP traits was 96% of the theoretical rate. The only intentional selection in these materials was for bacterial blight resistance. As expected, the
level of blight resistance in the Bc4F4 reflected that of its NRP. Also as expected, the level of tolerance to Verticillium wilt and of resistance to the Fusarium wilt/rootknot nematode complex in the Bc4F4 reflected that of the RP with three possible exceptions.
Impacts
Backcross breeding is a relatively simple, predictable method (commonly used in cotton) to improve a variety by incorporating one or two, never more than a few, traits into it from another source. This research measured the degree and rate of recovery of traits from the cotton variety being improved and should make future use of the method more efficient.
Publications
- BAYLES, M.B., VERHALEN, L.M., McCALL, L.L., JOHNSON, W.M., and BARNES, B.R. 2005. Recovery of recurrent parent traits when backcrossing in cotton. Crop Sci. 45:2087-2095.
- BAYLES, M.B., VERHALEN, L.M., JOHNSON, W.M., and BARNES, B.R. 2005. Trends over time among cotton cultivars released by the Oklahoma Agricultural Experiment Station. Crop Sci. 45:966-980.
- FARRIS, R.L., GRAY, C.J., MURRAY, D.S., and VERHALEN, L.M. 2005. Time of removal of crownbeard (Verbesina encelioides) on peanut yield. Weed Technol. 19:380-384.
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Progress 10/01/03 to 09/30/04
Outputs
Glyphosate-tolerant and bromoxynil-resistant cotton give producers additional postemergence (POST) weed control options, but these technologies require planning of weed management practices in advance of planting the crop, thus increasing the complexity of decision making. Herbicide Application Decision Support System (HADSS) is a computer program designed to help those confronted with making such decisions. The HADSS database (from North Carolina) was modified to adapt it more closely to Oklahoma conditions and cotton production systems. Seven field experiments were conducted in Oklahoma in 1999 and 2000 to validate those changes (i.e., to determine if HADSS can recommend POST treatments that are effective and economical in the state). HADSS treatments and results were compared with those made jointly by two weed scientists, designated as the 'Expert'. Similar herbicides and herbicide combinations were recommended by HADSS and the Expert; occasionally, they were
identical. Control of eight weed species was similar for the HADSS or the Expert treatments when they received the same preplant incorporated (PPI) and preemergence (PRE) herbicide regimes. Within systems having the same PPI or PRE herbicides, HADSS and the Expert treatments resulted in similar cotton lint yields in 42 of 46 possible comparisons (91%). HADSS treatments had higher yields in the other four (9%). Adjusted net returns were not different between HADSS and Expert treatments in 38 of 46 possible comparisons (83%). HADSS treatments gave higher returns in the remaining eight (17%); half were due to higher yields, and half to lower herbicide costs. The adapted program can aid decision making for efficient and economical POST herbicide applications in Oklahoma cotton.
Impacts
Cotton in Oklahoma is produced under biotic and abiotic environmental conditions which limit its yield and fiber quality. This research helps reduce the negative effects of those conditions, thus making cotton production more profitable.
Publications
- MURDOCK, S.W., MURRAY, D.S., VERHALEN, L.M., and MEDLIN, C.R. 2004. Adaptation and validation of HADSS for cotton production in Oklahoma. J. Cotton Sci. 8:42-54 [Online]. Available at http://journal.cotton.org (verified 13 Dec. 2004).
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Progress 10/01/02 to 09/30/03
Outputs
Transgenic cotton with Bollgard (BG), Roundup Ready (RR), or both (BG/RR) was studied to see if it influenced lint yield, lint percent, and fiber quality. Field trials were conducted as if for conventional (i.e., nontransgenic) cotton at two irrigated locations over 2 years. BG was stable for lint yield across genetic backgrounds, but RR was not. BG increased yield across backgrounds in three of four tests (from 6.7 to 11.8%), averaging 6.2% over all four. In one background, RR decreased yield in two tests (from -7.3 to -22.2%), but increased it (12.7%) in another. RR increased yield (10.5%) in another background in one test, but had no influence in two other backgrounds. Clearly, RR can reduce yield in some backgrounds in some environments. BG/RR increased yield by 2.5 and 16.8% in two backgrounds over four tests. In BG/RR, the higher yields associated with BG apparently overcame the occasional deficits associated with RR. BG/RR increased yield by 8.6 and 9.0% above
RR in two backgrounds over four tests. In another background, the increase was not significant. BG/RR (like BG) often increased yield, but caused no significant reductions. BG reduced picked lint percent and fiber fineness. RR increased pulled lint percent, had a neutral or negative effect on fiber length, and showed a neutral or positive effect on fineness. BG/RR reduced fiber length, length uniformity, strength, and elongation, but increased fineness. Relative to RR, BG/RR had a neutral or negative influence on picked lint percent, length uniformity, fineness, and strength.
Impacts
Cotton in Oklahoma is produced under biotic and abiotic environmental conditions which limit its yield and fiber quality. This research helps reduce the negative effects of those conditions, thus making cotton production more profitable.
Publications
- VERHALEN, L.M., GREENHAGEN, B.E., and THACKER, R.W. 2003. Lint yield, lint percentage, and fiber quality response in Bollgard, Roundup Ready, and Bollgard/Roundup Ready cotton. J. Cotton Sci. 7:23-38 [Online]. Available at http://journal.cotton.org (verified 24 Nov. 2003).
- BAYLES, M.B., ESSENBERG, M., PIERCE, M.L., and VERHALEN, L.M. 2003. A pyramid of near-isogenic lines of cotton with 0, 1, 2, or 3 genes for bacterial blight resistance. Phytopathology 93:S7 (Abstr.).
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Progress 10/01/01 to 09/30/02
Outputs
With Essenberg and her colleagues, the development and genetic characterization of four near-isogenic lines (NILs) of cotton were completed. Each NIL carries a different, homozygous, single gene for resistance to bacterial blight (i.e., B2, B4, BIn, or b7). The NILs were derived using at least six backcrosses to the susceptible recurrent parent 'Acala 44' and are designated as AcB2, AcB4, AcBIn, and Acb7, respectively. Relative strengths of resistance to race 1 of the pathogen were also described for each NIL as well as their responses to a set of pathogen lines each carrying a single avirulence gene. With Murray and his colleagues, the effects of six johnsongrass densities on cotton were investigated. With three or fewer weeds/15 m of row in 1 year and four or fewer in the following year, harvest efficiencies were 4.9 to 7.6% higher for stripper- than for picker-harvested cotton. At higher densities, differences in harvest efficiency between the two machines were not
significant. Over both years, picker-harvest lint yield was reduced 32 to 43 kg/ha (3.9 to 5.5%) for each weed/15 m of row; and stripper-harvest lint yield was reduced 29 to 43 kg/ha (3.5 to 5.2%). The influences on fiber properties and loan rate were also investigated.
Impacts
(N/A)
Publications
- ESSENBERG, M., BAYLES, M.B., SAMAD, R.A., HALL, J.A., BRINKERHOFF, L.A., and VERHALEN, L.M. 2002. Four near-isogenic lines of cotton with different genes for bacterial blight resistance. Phytopathology 92:1323-1328.
- WOOD, M.L., MURRAY, D.S., BANKS, J.C., VERHALEN, L.M., WESTERMAN, R.B., and ANDERSON, K.B. 2002. Johnsongrass (Sorghum halepense) density effects on cotton (Gossypium hirsutum) harvest and economic value. Weed Technol. 16:495-501.
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Progress 10/01/00 to 09/30/01
Outputs
Four experiments were conducted in the field to determine whether BOLLGARD (BG) has a positive, neutral, or negative effect on lint yield of upland cotton under irrigation in Oklahoma and to do likewise for ROUNDUP READY (RR) and for BG/RR. BG increased lint yield in three of four experiments (from 6.7 to 11.8%) compared to its recurrent parents 'PM 1215' and 'DP 5415'. No significant interactions with genetic background were detected for this gene. RR decreased lint yield of 'PM 1220' in two trials (from -7.3 to -22.2%), but increased it (12.7%) in another. An increase of 10.5% was noted for 'PM 1244' in one trial. No effects were detected in PM 1215 and DP 5415. Significant interactions with genetic background were detected for RR in three of four tests. BG/RR increased lint yield in PM 1220 (from 10.0 to 22.2%) compared to RR in two of four experiments; it increased yield in PM 1244 (from 6.4 to 12.9%) relative to RR in three. No effects were detected in 'PM 2326'.
Significant interactions between BG/RR vs. RR were observed in two of four trials. BG/RR increased lint yield (11.7%) in PM 1220 in one experiment compared to the recurrent parent and in PM 1244 (from 12.4 to 23.8%) in three. Significant interactions between them were observed in three tests. BG (alone or in combination with RR) may or may not increase lint yield in upland cotton. BG did not vary significantly on different genetic backgrounds. RR may or may not increase (or decrease) lint yield in cotton. RR (alone or in combination with BG) frequently displayed significant interactions indicating that the expression of that gene is influenced by genetic background.
Impacts
(N/A)
Publications
- VERHALEN, L.M., GREENHAGEN, B.E. and THACKER, R.W. 2001. Lint yield response of BOLLGARD (BG), ROUNDUP READY (RR), and BG/RR cotton under irrigation in Oklahoma. p. 419. In Proc. Beltwide Cotton Conf., Anaheim, CA. 9-13 Jan. 2001. Natl. Cotton Counc. Am., Memphis, TN.
- ALBERS-NELSON, M.R., MURRAY, D.S., VERHALEN, L.M. and GOAD, C.L. 2000. Establishment techniques for common cocklebur (Xanthium strumarium). Weed Technol. 14:463-470.
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Progress 10/01/99 to 09/30/00
Outputs
Cross-pollination in cotton was estimated at seven Oklahoma locations for up to 22 years/location using a homozygous glandless line (grown as a single progeny row and surrounded by glanded cotton). Objectives of the study were to describe the variation in cross-pollination of cotton among locations in the state and over years at each location and to characterize the degree of cross-pollination in cotton as a crop. Cross-pollination counts at Perkins were very high. On dryland, they ranged from 50.9 to 72.6% (averaging 62.7%). Under irrigation, they varied from 43.9 to 75.4% (excluding 1996 when multiple insecticide applications were made) and averaged 63.2%. Counts at Chickasha were high. On dryland, they ranged from 28.1 to 56.7% (averaging 43.8%). Under irrigation, they varied from 35.0 to 48.9% (averaging 43.2%). Counts at Altus under irrigation were very low ranging from 0.1 to 3.8% (averaging 1.2%). In 5 of 10 years, they were less than 0.5%. In 7 of 10 years,
they were 1.1% or less. Counts at Mangum, Canute, Tipton, and Hollis were erratic...neither dependably high nor consistently low. Clearly, the best location for conventional cotton breeding (without selfing) is Altus. Perkins and Chickasha offer the greatest promise for hybrid production. Cotton cross-pollination ranged from 0.1 to 75.4%. It was never completely absent nor uniformly complete. The crop is clearly intermediate between the self- and cross-pollinated categories.
Impacts
(N/A)
Publications
- VERHALEN, L.M., GREENHAGEN, B.E. and SIMMONS, J.W. 1999. Long term study of cross-pollination in Oklahoma cotton. Proc. Beltwide Cotton Conf. p. 453. (Abstr.)
- GREENHAGEN, B.E. and VERHALEN, L.M. 1999. Cross-pollination in cotton winter nurseries. Proc. Beltwide Cotton Conf. p. 453. (Abstr.)
- VERHALEN, L.M., WILLIAMS, O.H. and GREENHAGEN, B.E. 1999. Adjusting seeding rates to optimize stands of cotton. Oklahoma Coop. Ext. Serv. Current Rept. CR-2118. 2 pp.
- ROWLAND, M.W., MURRAY, D.S. and VERHALEN, L.M. 1999. Full-season Palmer amaranth (Amaranthus palmeri) interference with cotton (Gossypium hirsutum). Weed Sci. 47:305-309.
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Progress 10/01/98 to 09/30/99
Outputs
Cross-pollination in cotton was estimated at seven Oklahoma locations for up to 22 years/location using a homozygous glandless line (grown as a single progeny row and surrounded by glanded cotton). Objectives of the study were to describe the variation in cross-pollination of cotton among locations in the state and over years at each location and to characterize the degree of cross-pollination in cotton as a crop. Cross-pollination counts at Perkins were very high. On dryland, they ranged from 50.9 to 72.6% (averaging 62.7%). Under irrigation, they varied from 43.9 to 75.4% (excluding 1996 when multiple insecticide applications were made) and averaged 63.2%. Counts at Chickasha were high. On dryland, they ranged from 28.1 to 56.7% (averaging 43.8%). Under irrigation, they varied from 35.0 to 48.9% (averaging 43.2%). Counts at Altus under irrigation were very low ranging from 0.1 to 3.8% (averaging 1.2%). In 5 of 10 years, they were less than 0.5%. In 7 of 10 years,
they were 1.1% or less. Counts at Mangum, Canute, Tipton, and Hollis were erratic...neither dependably high nor consistently low. Clearly, the best location for conventional cotton breeding (without selfing) is Altus. Perkins and Chickasha offer the greatest promise for hybrid production. Cotton cross-pollination ranged from 0.1 to 75.4%. It was never completely absent nor uniformly complete. The crop is clearly intermediate between the self- and cross-pollinated categories.
Impacts
(N/A)
Publications
- Verhalen, L.M., Greenhagen, B.E. and Simmons, J.W. 1999. Long term study of cross-pollination in Oklahoma cotton. Proc. Beltwide Cotton Conf. p. 453. (Abstr.)
- Greenhagen, B.E. and Verhalen, L.M. 1999. Cross-pollination in cotton winter nurseries. Proc. Beltwide Cotton Conf. p. 453. (Abstr.)
- Verhalen, L.M., Williams, O.H. and Greenhagen , B.E. 1999. Adjusting seeding rates to optimize stands of cotton. Oklahoma Coop. Ext. Serv. Current Rept. CR-2118. 2 pp.
- Rowland, M.W., Murray, D.S. and Verhalen , L.M. 1999. Full-season Palmer amaranth (Amaranthus palmeri) interference with cotton (Gossypium hirsutum). Weed Sci. 47:305-309.
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Progress 10/01/97 to 09/30/98
Outputs
A contributing factor toward excessive plant populations in cotton fields has been identified and quantified. Seed analysis tags in cotton commonly guarantee a minimum germination of 80%. To determine actual germination percentages, multiple samples of many varieties of commercial cottonseed were submitted to the Okla. Crop Improvement Assoc. over a 5-year period for testing. Average germination was 90.1, 93.7, 96.7, 93.0, and 90.5% in 1994 through 1998, respectively. Clearly, if a producer assumes 80% germination for the seed he plants and it's actually 90%+, he's planting too many pure live seed per acre. A more accurate germination percentage would enable him to achieve closer to optimum stands.
Impacts
(N/A)
Publications
- WESTERMAN, R.B., MURRAY, D.S., VERHALEN, L.M., HACKETT, N.M., CASTNER, E.P., BANKS, J.C., STONE, J.F. and WEEKS, D.L. 1998. Hogpotato (Hoffmanseggia glauca): Its biology, competition, and control. Oklahoma Agric. Expt. Sta. Bull. B-812. 21 pp.
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Progress 10/01/96 to 09/30/97
Outputs
Experiments were conducted to more accurately determine the optimum planting date (or time interval) for irrigated cotton production in Oklahoma and in surrounding areas of Texas. Two varieties (a picker and a stripper type), seven planting dates/year, and five years were investigated under irrigation near Altus. The experimental design was a split-plot with whole plots randomly assigned in a RCB with four replications. Subplots were randomly allotted to planting dates. Maximum lint yields were obtained for the 2-week time interval including planting dates (PD) 3 and 4 (May 15 and 22). PD 2 (May 8) and PD 5 (May 29) lowered lint yield 4 to 5%. PD 1 (May 1) and PD 6 (June 8) lowered lint yield an additional 9 to 11%. PD 7 (June 15) lowered lint yield 30% relative to PD 3 and 4. Lint percent declined by 0.3% and micronaire by 0.1 units for each week that planting was delayed. Numerous other studies are in various stages of completion, analysis, and publication.
Impacts
(N/A)
Publications
- LARSON, J.A., MAPP, H. P., VERHALEN, L.M. and BANKS, J.C. 1996. Adapting a cottonmodel for decision analyses: A yield-response evaluation. Agric. Syst. 50:145-167.
- ROGERS, J.B., MURRAY, D. S., VERHALEN, L.M. and CLAYPOOL, P.L. 1996. Ivyleaf morningglory (Ipomoea hederacea) interference with cotton (Gossypium hirsutum). Weed Technol. 10:107-114.
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Progress 10/01/95 to 09/30/96
Outputs
Adapting a general crop growth model (simulator) to a specific locale and validating it present a number of conceptual and practical difficulties. Methods which were used to adapt the COTTAM simulator for the irrigated-cotton planting decision in the Oklahoma Rolling Plains are described as well as an evaluation of the response relationships in the model. COTTAM was adapted by considering how user inputs influence lint yield response as a function of planting date, seeding rate, plant population, and variety type. Those factors were used to define the sources of dynamics and risk in making decisions at planting time. Regression methods were used to estimate production functions for simulated yield as derived from the adapted model. Technical relationships derived from parameter estimates were used to evaluate output of the adapted model. The relationships estimated from adapted simulator output corresponded to those hypothesized from the literature and estimated from
available field data. The adapted COTTAM simulator is a useful tool for ranking irrigated-cotton decision alternatives in Oklahoma.
Impacts
(N/A)
Publications
- LARSON, J.A., MAPP, H. P., VERHALEN, L.M. and BANKS, J.C. 1996. Adapting a cottonmodel for decision analyses: A yield-response evaluation. Agric. Syst. 50:145-167.
- ROGERS, J.B., MURRAY, D. S., VERHALEN, L.M. and CLAYPOOL, P.L. 1996. Ivyleaf morningglory (Ipomoea hederacea) interference with cotton (Gossypium hirsutum). Weed Technol. 10:107-114.
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Progress 10/01/94 to 09/30/95
Outputs
Steps were taken to adapt COTTAM (a cotton growth model) to Oklahoma irrigated cotton production and to evaluate the adapted model's output. (1) A literature review was conducted; and available information from the locale was accumulated to evaluate planting date, seeding rate, plant population, and cultivar type. Hypotheses for lint yield were developed relative to each management alternative. (2) Plant and field parameters were estimated using information from the locale if available and from the literature if not. Parameters required were plant population survival, first main-stem fruiting branch node number, and boll weight plus soil characteristics, daily weather, etc. Those factors were used to define yield response and demarcate sources of dynamics and risk for this location. (3) The range of choices that a producer might consider at planting time were simulated using the adapted simulator and local climatic data. (4) Production functions were estimated, and
technical relationships were derived to evaluate yield response. The adapted model adequately described how yield is influenced by changes in planting date, seeding rate, plant population, and cultivar type. Consequently, COTTAM is a useful tool for ranking irrigated-cotton decision alternatives in Oklahoma. Additional work is required to expand COTTAM to include other decisions and sources of risk (e.g., insect control, nutrient stresses, methods of harvest). A journal article in Agricultural Systems is "in press".
Impacts
(N/A)
Publications
- LARSON, J.A., MAPP, H.P., VERHALEN, L.M. AND BANKS, J.C. 1994. Evaluating crop simulator yield response using production economic concepts. Am. J. Agric. Econ. 76:1273. (Abstr.).
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Progress 10/01/93 to 09/30/94
Outputs
Experiments were conducted in a growth chamber to compare the prometryn tolerance of glanded vs. glandless `Empire 61 (WR)' and `Westburn M' isolines. Two intermediately glanded Empire isolines (Gl(subscript 2)Gl(subscript 2)gl(subscript 3)gl(subscript 3) and gl(subscript 2)gl(subscript 2)Gl(subscript 3)Gl(subscript 3)) were also available for analysis. Ratios derived from leaf chlorophyll fluorescence measurement curves established that the photosynthetic inhibition caused by prometryn in glanded cotton seedlings was of less intensity and shorter duration than in glandless plants within the same genetic background. Comparisons involving the intermediately glanded Empire isolines suggested that Gl(subscript 2) enhances seedling tolerance more than does Gl(subscript 3). Glanded vs. glandless isolines in five genetic backgrounds (i.e., Empire 61 (WR), Westburn M, `Delcot 277', `TH 149', and `Stoneville 213') plus the two intermediate Empire isolines were also evaluated
for prometryn tolerance in the field. Visual crop injury ratings and measured lint yields support the growth chamber data. The treated glanded isoline on each background displayed less injury (20-56%) and higher yield (44-60%) than the corresponding glandless isoline. Again, Gl(subscript ,) showed less injury than Gl(subscript 3) though differences in lint yield were not significant.
Impacts
(N/A)
Publications
- FOSTER, J.D., JR., VERHALEN, L.M. and MURRAY, D.S. 1994. Prometryn tolerance in glanded versus glandless isolines of cotton. Crop Sci. 34:67-71.
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