COTONS, A Cotton Simulation Model for the Next Century

ABSTRACT
Traditional plant architectural models or ‘visualization models’ propose to visually create realistic three-dimensional plants. The visualization is based on field sampling and the application of an algorithm to standardize the three-dimensional description of a plant. “L-systems” and the “Reference Axis” are two such approaches. Mechanistic or physiologically based models, built using mathematical expressions of the interactions between plant components propose to describe how a plant functions. They simulate physiologically realistic plants based on estimates of physiological development and growth. Their equations are derived from field experiments. In this study we integrated both modeling paradigms. We used functions and concepts obtained from mechanistic and architectural modeling theories and developed an integrated system. The system was derived from an enhanced ‘mechanistic’ model, GOSSYM, with 3D architectural extensions. We accomplished this by associating growth and development functions with actual locations in three-dimensional space. The resulting model allows vastly improved model output interpretation, use of the model as a surrogate experimental environment and to better integrate our knowledge about how plants grow into a unique system. The new model, named COTONS, produces “life-like” plants. Now the farmer deals with simulation results analogous to the ones he deals with in a 3-dimensional world. Very importantly, variability is captured and expressed visually. This is the first step for better characterizing production risk in human-based terms. This new model symbolizes crop models for the next century.

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Modeling Light-Interception for a Cotton Population Model

ABSTRACT
Light-interception by crops has been intensively studied since the early 1960s. Simple models of light interception for single plant, crop-rows, and for continuous canopy have been developed. More complex models, using crop geometry, have also been investigated and some of the studies tried to model plant competition. However, the majority of these light models have not been integrated with models of photosynthesis and plant growth. Since the beginning of the 1970s up to fifteen different models of cotton development have been proposed and published. Some of them have been proposed for management but none of these models integrate a light interception sub-model able to simulate light interception for competing plants. In this study we developed a new light model based on some of the main crop architectural and agronomic characteristics. This new model was integrated with the GOSSYM-COMAX decision support system, and it gives the same results for the conditions where the original model was valid. It is also able to simulate the effects of plant competition for light. The new model provides the foundation for a plant population model as an alternative to currently used average plant models.

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Validation and Application of GOSSYM

ABSTRACT
A field experiment was conducted at Alcalá del Rio (Seville, Spain) on a sandy loam soil in 1994. Three cotton cultivars (Maria del Mar, Deltapine 90 and Deltapine 20) were studied. The statistical model had four splits in the following order: irrigation, density, fertilization and genotypes. Plant height evolution, main stem node number and fruit distribution were quantified on several dates during the season. The model predicted plant height, and number of main stem nodes in the first stages of development, mainly when the file mapping option was used. However, the model did not accurately predict seed cotton yield, flowering and open boll dates at the end of the season. Corrections are needed in GOSSYM to simulate cotton cultivation in Spain with reference to plastic mulch, cultivars, climate and soil type.

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Evaluation of GOSSYM – a Cotton Crop Simulation Model – Under the Soil, Climatic and Cultural Conditions in Greece

ABSTRACT
In a research study in Greece, funded by EU, a dynamic cotton growth simulation model, GOSSYM, was evaluated under local soil, climatic and cultural conditions. Field experiments were conducted for three years in three locations, representative of major cotton growing areas of Greece, using four cotton cultivars under two irrigation levels, two fertilization treatments and two plant populations. The variables ranged from conventional to low input values. Weather conditions varied among the three years of experimentation. Soil analyses and weather data were collected according to GOSSYM input requirements and plant growth and yield was monitored through the growing season. The last year of the study the design included comparison of two management schemes, a conventional farmer approach and a low input strategy as suggested by the previous two years results and GOSSYM simulations. The comparison between field measured and simulated values showed a satisfactory simulation of yield and some plant characteristics and a very close simulation of total water used as ET. The results indicated that GOSSYM could be used as a cotton management tool to optimize cotton production in Greece after some variety calibration and soil and climatic site specific sites.

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Effects of NaCl stress on the biochemical substances in Bt cotton as well as on the growth and development and adult oviposition selectivity of Helicoverpa armigera

Background

Recently, due to the development of food security strategies, cotton has been planted in inland saline-alkali dry soils or in coastal some saline-alkali soils in China. Under the condition, to comprehensively prevent and control Helicoverpa armigera in cotton fields with saline-alkali soils, it is important to study the larval growth and development of H. armigera and to study adult oviposition selectivity in H. armigera adults that feed on NaCl-stressed cotton plants.

Results

In this study, Bt cotton GK19 was used for the experimental group and its nontransgenic parent Simian 3 was used for the control to study the effects of biochemical substances in cotton as well as larval growth and development and adult oviposition selectivity of H. armigera. The experiments were performed by growing cotton indoors under NaCl stress at concentrations of 0 mmol·L− 1, 75 mmol·L− 1 and 150 mmol·L− 1, respectively. The results showed that the expression of Bt protein was significantly inhibited for NaCl-stressed Bt cotton. The content of soluble protein and K+ in the leaves of cotton were decreased, while the content of gossypol and Na+ were increased. In addition, the 5th instar H. armigera larvae exhibited shorten the life span in a 13-day trial period. Under enclosure treatments and at different female densities, the adult oviposition of H. armigera decreased on high NaCl-stressed nontransgenic cotton, while the oviposition on Bt cotton tended to first increase but then decrease under low, moderate and high NaCl stress treatments.

Conclusions

Under certain content ranges of NaCl stress treatments, larval of H. armigera growth and development, and adult oviposition were no significant difference in the change for a certain period. However, under high NaCl stress, larval growth, development and adult oviposition were affected, which may provide insights for the prevention and control of H. armigera for Bt cotton in saline-alkali soils.

 

Effects of NaCl stress on the biochemical substances in Bt cotton as well as on the growth and development and adult oviposition selectivity of Helicoverpa armigera

LUO Junyu, ZHANG Shuai, ZHU Xiangzhen, JI Jichao, ZHANG Kaixin, WANG Chunyi, ZHANG Lijuan, WANG Li and CUI Jiniie

Journal of Cotton Research. 2019; 2:4

https://doi.org/10.1186/s42397-019-0020-7

 

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0020-7

Twenty-Five Years after Beasley and Ting: Revealing Fundamental Properties of Fiber-Growth with Cotton Ovule Cultures

ABSTRACT
Since the initial description of culture conditions for growing fiber in vitro by Beasley and Ting in 1973 many laboratories, including the Cotton Fiber Bioscience Research Unit, have used cotton ovule cultures to answer questions about fiber development. Fiber growth on developmental mutants cultured in vitro was similar to patterns seen in planta, however subtle differences in the production of cell wall polymers were detected by gel permeation chromatography of cultured fibers compared with in planta fibers. Fiber cells from cotton ovule cultures proved to be exceptional starting material for isolating cytoskeletons from plant cells for biochemical characterization. Adding alpha-amanitin to ovule cultures inhibited the normal progression of fiber development depending on when the transcription inhibitor was added. The inhibition was reversible during the early stages of fiber initiation and cell elongation, but irreversible if ovules were left in contact with alpha-amanitin for greater than five days. This observation suggests that there is a window of opportunity for fiber cell initials to develop into elongated fiber cells. If fiber cells do not differentiate within 4-6 days post-anthesis, fibers lose their capacity to differentiate. Current research is directed toward showing that the same mechanisms leading to the loss in capacity to differentiate operate to regulate gene expression during fiber development. Our laboratory is also developing conditions that will be suitable for growing cotton ovule cultures aboard the International Space Station to monitor the effects of microgravity on fiber gene expression and cell wall structure.

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ASSET as an In-Furrow Application to Enhance Early-Season Growth and Lint Yield

ABSTRACT
The establishment of a uniform and vigorous stand is essential for producing a high yielding cotton (Gossypium hirsutum L.) crop. Germination, emergence and seedling establishment are adversely affected by unfavourable environmental conditions often experienced in the Mississippi Delta Region of the USA. Preplant in-furrow applications of fertilizer additives have been reported to enhance root growth, water and nutrient uptake and lint yield potential. ASSET was applied in-furrow to cotton grown under field and controlled environmental conditions and the effect on seedling emergence, plant height, root growth and lint yield measured. In the controlled environment studies, seedling emergence was enhanced at six days after planting (DAP). Leaf area, total root length, and the number of lateral roots were numerically higher at four weeks after planting. Plants exposed to cooler temperatures and mechanical damage (removal of one cotyledon) had higher total dry weights; however, differences were not significant or consistent. Results from field studies were variable and inconsistent. Seedling emergence was slightly enhanced in the ASSET treatment in two of the three years of field data (1996 and 1997). Plant height at 73 DAP (1996) increased when compared with the untreated control although differences were not significant. The number of squares in the ASSET treatment in 1997 was significantly higher (P<0.05) indicating a potential for higher lint yield. Yields were not significantly increased in 1997. Yield data from the field study in 1998 are not available yet. Though the data are still inconclusive, ASSET appears to offer some advantage in promoting early season root growth but the effects on lint yield have been non-significant. Additional research is needed to observe the effects of ASSET on lint yield and on cotton seedlings exposed to stress conditions that represent at potential climatic conditions at planting.

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Sucrosyl Oligosaccharide Metabolism and Cotton Fiber Development

ABSTRACT
The object of this study was to determine which oligosaccharides correlate with cell wall synthesis in developing cotton fibers. This study employed bolls taken from sequential fruiting branches on the same plant to rule out environmental and plant to plant differences. Cold aqueous extracts of developing cotton fibers have been analyzed by HPAEC-PAD (Murray, 1998). Sucrosyl oligosaccharides appear to function as cell wall precursors. A decrease in sucrose concentration and a concomitant increase in raffinose concentration characterize maximal secondary wall synthesis in cotton fibers. We have confirmed the identification of raffinose, stachyose, verbascose and tentatively identified ajugose and other sugars in the series. Environmental conditions appear to influence the concentrations of glycerol, m-inositol, galactinol, melibiose, and manninotriose in developing cotton fibers. The relative concentrations of sucrosyl oligosaccharides were found to vary fibers from plants subjected to high stress in irrigation experiments. Differences in glycoconjugate profiles in the fibers are apparent in irrigation experiments several days before significant differences are apparent in leaf water potentials. Differences in glycoconjugate profiles are also apparent in fibers from bolls collected at 7am, noon and 7pm suggestive of a diurnal rhythm. This diurnal variation is of interest since the major portion of cell wall deposition occurs at night. (Murray, A. K., 1998, U.S. Patent No. 5,710,047).

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Cell Wall Subunits, “Glue” Matrix and Cotton Fiber Development

ABSTRACT
The object of this study was to isolate and characterize the cell wall subunits and “glue” matrix involved in cell wall synthesis in developing cotton fibers. This study employed fibers taken from 25DPA bolls collected at 7am, noon and 7pm. Cold aqueous extracts of developing cotton were analyzed by HPAEC-PAD (Murray, 1998). Subsequent sequential extracts were taken on a daily basis at three temperatures, 37°, room temperature and 4°. Extracts were fractionated by centrifugation and filtration. The fractions of the extracts were subjected to alkaline borohydride, mild acid, protease digestion or glycosidase treatment followed by PAGE and HPAEC-PAD (Murray, 1998). The cell wall subunits and “glue” matrix were found to vary both in the quantity extracted and in the character of the “glue” matrix extracted. This variability is dependent both on the time of day that the fibers were collected and the temperature of the extraction. The extracts demonstrated the ability to synthesize the “glue” matrix by a temperature dependent mechanism that “consumed” hexoses in the process and released apparent carriers. The “glue” matrix appears to add carbohydrate residues to the subunits in the matrix after the initial carbohydrate residues are conjugated. The enzymatic activities associated with the “glue” matrix will be discussed. (Murray, A. K., 1998, U.S. Patent No. 5,710,047).

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Genetic Variability for Root Development in Cotton

ABSTRACT
Cotton root system development is under genetic control and continuously influenced by the environment. Root architectural diversity can influence the overall productivity of the plant since both uptake and distribution of water and nutrients are impacted by the size and distribution of the root system. The impact of various environmental factors on the phenotypic expression of exotic accessions and modern cotton cultivar root systems was evaluated. Plants were grown in aeroponic, hydroponic, and soil systems and the development of root mass, root length, root extension rates and root architecture were measured. Significant differences in root length development and root architecture were observed among the cotton lines evaluated. Genetic diversity in the rooting response to pruning and temperature were also observed. These findings should aid in developing germplasm for improved response to adverse environments and increased plant productivity.

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