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Over the last 20 years, planting seed quality in cotton has improved due to several factors including better seed processing techniques and improvements in seed treatment fungicides/technology. Optimal plant populations in the field have become easier to achieve due to the aforementioned reasons, as well as later planting dates and less disease pressure. Additionally, reduced phytotoxicity from residual herbicide applications has improved cotton stands.
Many of the varieties today are less determinate and respond to lower populations with a reduced tendency to have excessive agronomic growth. The opposite is true in higher populations where vegetative growth can become very difficult to manage, particularly in the event of insect- or climate-induced fruit shed. For these reasons, many growers are planting reduced populations. These populations are in the 40,000 seeds/acre range versus the historical 55,000 seeds/acre. In 2011, the Scott Learning Center evaluated the interaction of cotton variety, population, and plant growth regulator (PGR) use on cotton height at cutout and lint yield.
A demonstration trial was conducted at the Monsanto Learning Center in Scott, Mississippi to evaluate the effects of cotton variety, plant population, and PGR rates/timing on plant height at cutout and lint yield. Numerous growers in the South fluidly move from cotton to corn and vice versa. For this reason, understanding how the two crops are different with respect to emergence and population is important.
Four Deltapine® cotton varieties were planted at seeding rates of 28,000; 41,000; and 55,000 seeds/acre (Table 1). These populations represented 2, 3, and 4 seeds/foot. Two PGR regimes were implemented: passive and aggressive (Table 1). All varieties Table 1. Description of variables evaluated in this study. were Genuity® Bollgard II® with Roundup Ready® Flex cotton. Planting occurred on May 12, 2011 and harvest was September 20. Plant height at cutout and yield data were collected.
Population. Across both PGR treatments, acceptable yields were achieved even at the lowest population. At 28,000 seeds/acre, cotton yield was 2103 lbs lint/acre, while yields were 1957 and 2166 lbs lint/acre at 41,000 and 55,000 seeds/acre, respectively, when averaged across PGR treatments.
On average, 68% of the seed planted produced a plant for harvest. Emergence conditions were very good this season. This cotton stand result is similar to the 70% average observed at the Scott Learning Center; however, it is much lower than the 99% emergence observed in corn at the Scott Learning Center.
PGR. Across populations, the aggressively treated cotton yielded slightly more than the passively treated cotton (Figure 1). When averaged across populations, the aggressive PGR system (2097 lbs lint/acre) yielded 43 lbs lint/acre more than the passive system (2054 lbs lint/acre). Plant height was reduced more in the aggressive system (average plant height of 54 inches) than in the passive (average plant height of 60 inches), but it varied with the growth habit of the variety (Figure 2). Large differences in average plant height were not observed across populations in either the aggressive PGR or passive PGR system (Figure 2).
Variety. All four varieties yielded very well in the demo, with average yields ranging from 1848 lbs lint/acre in DP 1137 B2RF to 2245 lbs lint/acre in DP 1048 B2RF. Most of the varieties follow the trend of 2200 Aggressive PGR Passive PGR needing more aggressive PGR management at higher populations but to varying degrees depending on determinancy level (Figure 3).
All varieties in the aggressive PGR system 2400 2000 1800 1600 1400 1200 1000 responded similarly with shorter plant height 800 compared to the passive PGR system (Figure 4). Additionally, the average plant height for all 4 varieties in the aggressive treatment was very similar; 55 inches for all varieties but DP 1133 28,000 B2RF, and it was 53 inches.
Population x PGR. Important trends were observed when examining population x PGR system. Low populations yielded better in the passively managed PGR system (Figure 1). Mid populations were somewhat indifferent to PGR management regime. Higher populations typically yielded more when aggressively managed with PGR.
Conclusions While corn yield potential can be limited from the start of the season if the desired stand is not achieved, changes in cotton population may force shifts in management to make a cotton crop successful. This difference between corn and cotton allows for cotton management changes in response to planted vs. emerged populations.
In general, cotton responded positively in yield to:
This relationship can allow growers to design a management system suited to their farm based on the following:
Note: These results are not intended to provide you with a blueprint on how to grow any specific variety but merely to give the benefit of some research with them. Your experience and knowledge will remain an invaluable component to the successful management of any variety. This information is being provided to you to aid you in making decisions and giving advice regarding the management of these varieties. The information is not intended to totally supplant your experience and knowledge base on the proper management of your individual crops. The information discussed in this report is from a single site, non65533;? replicated, one65533;?year demonstration. This informational piece is designed to report the results of this demonstration and is not intended to infer any confirmed trends. Please use this information accordingly.
Monsanto Company is a member of Excellence Through Stewardship® (ETS). Monsanto products are commercialized in accordance with ETS Product Launch Stewardship Guidance, and in compliance with Monsanto’s Policy for Commercialization of Biotechnology-Derived Plant Products in Commodity Crops. Commercial product(s) has been approved for import into key export markets with functioning regulatory systems. Any crop or material produced from this product can only be exported to, or used, processed or sold in countries where all necessary regulatory approvals have been granted. It is a violation of national and international law to move material containing biotech traits across boundaries into nations where import is not permitted. Growers should talk to their grain handler or product purchaser to confirm their buying position for this product. Excellence Through Stewardship® is a registered trademark of Biotechnology Industry Organization. B.t. products may not yet be registered in all states. Check with your Monsanto representative for the registration status in your state. Individual results may vary, and performance may vary from location to location and from year to year. This result may not be an indicator of results you may obtain as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible. ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Roundup Ready® crops contain genes that confer tolerance to glyphosate, the active ingredient in Roundup® brand agricultural herbicides. Roundup® brand agricultural herbicides will kill crops that are not tolerant to glyphosate. Bollgard II®, Genuity and Design®, Genuity Icons, Genuity®, Respect the Refuge and Cotton Design®, Roundup Ready®, Roundup®, and Technology Development by Monsanto and Design® are trademarks of Monsanto Technology LLC. Deltapine® is a registered trademark of Monsanto Company. ©2011 Monsanto Company. ABT12122011