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© 2004 Plant Management Network. Investigating Storm Resistance in Spindle-Picked Upland Cotton Joel Faircloth, Assistant Professor, Virginia Tech, Suffolk 23437; Alexander Stewart, Assistant Professor, LSU Agricultural Center, Alexandria, LA 71302; Alan Harper, Retired County Agent, North Carolina Cooperative Extension Service, Raleigh 27695; Keith Edmisten, Professor, North Carolina State University, Raleigh 27695; and Randy Wells, Professor, North Carolina State University, Raleigh 27695 Corresponding author: Joel Faircloth. jfaircloth@vt.edu Faircloth, J., Stewart, A., Harper, A., Edmisten, K., and Wells, R. 2004. Investigating storm resistance in spindle-picked upland cotton. Online. Crop Management doi:10.1094/CM-2004-0303-01-RS. Abstract In cotton (Gossypium hirsutum L.), storm resistance is an agronomic trait that identifies how tightly locks of fiber are held in open bolls. Delayed harvests often occur due to demands on harvest equipment, weather, commitment to other crops, and/or reliance on custom harvest. This study was conducted to evaluate the storm-resistant characteristics of commonly grown upland cultivars in spindle-picked cotton producing areas. Seedcotton loss of twenty cultivars was measured in 1996, 1997, 1999, and 2000 in the Coastal Plain of North Carolina. Yields were obtained in 1999 and 2000 to examine the significance of seedcotton losses associated with specific varieties. Significant differences exist among cultivars in terms of seedcotton loss during the latter part of the growing season. Sure Grow 501, Sure Grow 501 BG/RR, and Stoneville LA 887 consistently lost a relatively large amount of seedcotton in the years these cultivars were tested while Deltapine 5415 consistently lost a relatively small amount. However, both Sure Grow 501 and Sure Grow 501 BG/RR produced high yields and thus the significance of the seedcotton loss was not as detrimental as with other varieties. The relationship between seedcotton loss and relative maturity was mixed. This study suggests that storm resistance of spindle-picked upland cotton cultivars may have merit in cultivar selection and harvest scheduling. Introduction Storm resistance is an agronomic characteristic associated with cotton cultivars that refers to how tightly the locks of fiber are held in open bolls. Cultivars with good storm-resistant characteristics (i.e., fiber is held tightly) are desirable in stripper-harvested cotton producing areas where open cotton may be exposed to periods of wind, rain, and even snow prior to harvest. Cultivars lacking such characteristics may lose yield by dropping significant amounts of seedcotton on the ground when harvest is delayed. In spindle-picked cotton, storm resistance may also be a desirable characteristic when harvest is delayed. Young (11), however, stated that as lock tenacity (a measure of storm resistance) increased, harvest efficiency decreased. Thus, when harvest is completed in a timely manner, storm resistance may not be desirable. Investigations into storm-resistant characteristics have been limited largely to stripper-picked cotton. The term “lock tenacity,” coined by Young (10), was initially measured as the grams of force needed to remove the seedcotton from a boll using alligator-nosed battery clips. Dilbeck and Quisenberry (5) refined the instrumentation used by Young and began investigations into the heritability of storm-resistant traits in upland cotton. Quisenberry et al. (8) reported high lint yield was correlated with high lock tenacity at two locations of stripper-picked cotton in Texas, demonstrating the importance of lock tenacity in a once-over stripper-harvest system when harvest is delayed. In a later study, Quisenberry and Dilbeck (9) showed that increased lock tenacity was highly correlated to decreased storm loss. In a genotype by environment study of lock tenacity in Oklahoma, McCall et al. (7) found that the trait for a storm-resistant boll in stripper-harvested cotton was relatively stable over a range of environments. A number of factors may influence seedcotton loss from a particular cultivar. Extreme earliness may expose seedcotton to potential weather loss for a longer period of time. Friesen (6) reported that the following factors influence lock removal from the boll: fibers clamped in convolutions formed in the carpel wall during dehiscence, fibers pinched in the base of the burr, diseases affecting the fiber and carpel wall, friction between the fiber and carpel wall, protrusions along the boll suture, and a mucous-type substance left on the fiber acting as a gluing agent. All of these factors influence lock tenacity and storm resistance. Delayed harvest of spindle-picked cotton is often unavoidable due to large acreage, demands on equipment and labor, weather, reliance on custom harvests, and/or commitment to other crops. Little has been reported about the response of cultivars in spindle-picked areas to prolonged exposure to weather. The vast majority of information on cultivar storm resistance is anecdotal at best. The objectives of the following study were to evaluate 20 cultivars commonly grown in North Carolina for their storm-resistant characteristics under field conditions. Evaluating Storm-Resistance of Spindle-Picked Upland Cotton Twenty cotton cultivars were planted on a Pocalla loamy sand (sandy siliceous thermic Arenic Paleudult) near Kinston, NC on 21 May, 1996, 5 May, 1997, 5 May 1999, and 1 May 2000. In 1996, 1997, and 2000, 13 cultivars were early-maturing and seven cultivars were mid- to late-maturing. In 1999, 14 cultivars were early-maturing and six cultivars were mid- to late-maturing. Cultural practices recommended by the North Carolina Cooperative Extension Service were followed. The experimental design was a randomized complete block with four replications. Plot size was 50 ft long by four 38-inch-wide rows. In 1996, the two interior rows of each plot were planted with the cultivar assigned to the plot, while the outside two rows were planted with Deltapine 51 due to limited seed availability. In all other years, all four rows were planted with the assigned cultivar. Plots were defoliated in early October of each year. After defoliation, a burlap sheet 97 cm × 3 m long was placed in the row middle between the two center rows of each plot. Seedcotton that fell on the sheet was collected twice weekly from 14 October to 24 November in 1996, 14 October to 12 Dec in 1997, 9 November to 29 November in 1999, 1 November to 1 December in 2000, and weighed after air drying for three day. Seedcotton was collected 12 times in 1996, 16 times in 1997, six times in 1999, and nine times in 2000. Analysis of variance for overall seedcotton loss in all years and percent loss and yield in 1999 and 2000 was obtained using SAS GLM procedures (SAS Institute, 1997) and cultivar mean separation was achieved using Fisher’s protected least significant difference (LSD) at the 0.05 level of probability. Cultivars were grouped as either early- or mid- to late-maturing based on how they are entered in the North Carolina Official Cotton Variety Trial (1,2,3,4), and subjected to analysis of variance. Due to interactions, cultivar and maturity group means are presented by year. Mean percent of total seedcotton loss, over all 20 cultivars, for all collection dates falling within a particular weather category were subjected to analysis of variance with mean separation achieved using orthogonal contrasts in SAS GLM procedures (SAS Institute, Cary, NC). Because local weather conditions were extremely mild, weather data from 1999 and 2000 were not utilized in the analyses. Seedcotton Loss Affected by Cultivar and Harvest Schedule Seedcotton loss, in conjunction with percent loss and yields where applicable are presented by year because cultivars were added and deleted throughout the study based on the availability and usage (Tables 1, 2, 3, and 4). Significant differences for cultivar seedcotton loss were observed in all years and for percent loss and seedcotton yield in 1999 and 2000. Sure Grow 501 and Sure Grow 501 BG/RR consistently lost a large amount of seedcotton in all years they were used in the study (Table 1). However, these two cultivars also yielded relatively well in both 1999 and 2000 (Tables 3 and 4). Stoneville LA 887 also consistently lost a large amount of seedcotton in both years it was tested (Tables 1 and 2). Deltapine 5415 and Deltapine 5415 RR both lost very little cotton in 1999 and 2000 and also yielded relatively high in comparison to the other cultivars tested in 1999 and 2000. Some cultivars were not consistent in how they ranked among years. For example, Stoneville 474 ranked significantly higher than the majority of cultivars tested in 1996, 1999, and 2000 and significantly lower in 1997 (Tables 1, 2, 3, and 4). Reasons for the inconsistent response of some cultivars are unknown. The data do show, however, the potential of a particular cultivar to be susceptible to weather related seedcotton loss. Table 1. Cultivar seedcotton loss in 1996.
† Means within a column followed by the same Table 2. Cultivar seedcotton loss in 1997.
† Means within a column followed by the same Table 3. Cultivar seedcotton loss, percent loss of total yield, and
† Means within a column followed by the same letter do not differ Table 4. Cultivar seedcotton loss, percent loss of total yield, and
† Means within a column followed by the same letter do not differ The amount of seedcotton that a particular cultivar exposes to the elements at a given time can be related to maturity. Differences in maturity may potentially account for differences in observed seedcotton loss. Based on North Carolina Official Variety Trial maturity groupings (1,2,3,4), cultivars were labeled as either early- or mid- to late-maturing, and the mean of those groupings were analyzed by year because a significant maturity group by year interaction was found. An inconsistent response for seedcotton loss by maturity group was found (Table 5). In 1997, significantly more seedcotton was lost from mid- to late-maturing cultivars. In all other years, seedcotton loss was higher in the earlier maturing varieties with differences being significant in 1999 and 2000. However, because different varieties were used in each year it is difficult to make inferences concerning the influence of maturity on seedcotton loss. Table 5. Seedcotton loss of early- and mid- to late-maturity
Means within a column followed by the same letter do not ** Denotes significance at the 0.01 level of probability. * Denotes significance at the 0.05 level of probability.
These data are useful as both a harvest scheduling and variety selection tool. Characterizing a cultivar’s storm resistance based on research rather than anecdotal evidence can provide important information to cotton growers in supplementing accepted variety trial information. Producers use several factors in selecting cultivars such as yield, maturity, and fiber quality. Seedcotton loss as a percent of total yield potential for a cultivar is dependent on a cultivar’s yield potential in a particular environment, and could be expected to vary across environments. Because yield and fiber quality are highly influenced by soil type and environmental factors, producers should select cultivars from nearby variety trials that are most suited to their location based on yield and fiber quality data. The storm resistance of a certain cultivar should be influenced greatest by genotype. The storm-resistant boll trait in stripper-harvested cotton has been shown to be relatively stable across environments (7). Data found herein support this finding in upland cotton. Storm resistance in spindle-picked upland cotton is an area that has received little attention to date. The data reported here show that significant differences exist between cultivars. When combined with yield data, information regarding the storm resistance of a particular cultivar can be used in harvest scheduling. The data reported here should not be construed to be indicative of a cultivar’s actual expected seedcotton loss, but rather its potential for loss relative to other cultivars. Literature Cited 1. Bowman, D. T. 1996. North Carolina measured crop performance, soybean and cotton. Crop Sci. Res. Rep. No. 163. NC State Univ., Raleigh, NC. 2. Bowman, D. T. 1997. North Carolina measured crop performance, soybean and cotton. Crop Sci. Res. Rep. No. 172. NC State Univ. Raleigh, NC. 3. Bowman, D. T. 1999. North Carolina measured crop performance, soybean and cotton. Crop Sci. Res. Rep. No. 182. NC State Univ. Raleigh, NC. 4. Bowman, D. T. 2000. North Carolina measured crop performance, soybean and cotton. Crop Sci. Res. Rep. No. 188. NC State Univ. Raleigh, NC. 5. Dilbeck, R. E. and Quisenberry, J. E. 1979. Stormproof boll in upland cotton I. Development of instrumentation and inheritance study. Crop Sci. 19:567-570. 6. Friesen, J. A. 1968. Factors affecting removal of cotton from the boll. Am. Soc. Agric. Eng. 11:529-531. 7. McCall, L. L., Verhalen, L. M., and McNew, R. W. 1982. Genotype-environment interaction study of lock tenacity in upland cotton. Crop Sci. 22:794-797. 8. Quisenberry, J. E., Dilbeck, R. E., and Roark, B. R. 1980. Stormproof boll in upland cotton II. heritability and agronomic relationships. Crop Sci. 20:387-389. 9. Quisenberry, J. E. and Dilbeck, R. E. 1981. Stormproof boll in upland cotton III. Genotype-environment interaction and genetic analysis. Crop Sci. 21:511-514. 10. SAS Institute. 1997. SAS/STAT software: Changes in enhancements through release 6.12. SAS Institute, Cary, NC. 11. Young, E. F. 1975. Determining lock tenacity in pima cotton. Crop Sci. 15:59-61. |
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