Simulation Of Above-Ground Morphogenesis And Square-Boll Abscission Of Cotton

Based on the achievements in physiological and ecological mechanisms of the above-ground morphogenesis and square-boll abscission of cotton, the experiments including sowing-date, nitrogen, waterlogging, density conducted in the lower reaches of Yangtze River Valley (Nanjing, Dafeng and Dongtai) from2009to2011, we Systematically quantified the effects of the main environmental factors on the above-ground morphological indexes and square-boll abscission of cotton. Using agricultural model principle and systematic analysis method, we developed simulation model of nitrogen and waterlogging for the above-ground morphological indexes and square-boll abscission of cotton based on cumulative thermal and solar radiative effectiveness (TSE). Thus, introducing genetic effect and cumulative physiological, thermal and solar radiative effectiveness (TVE) as the driving variable is to simulate LAI and construct simulation model of cotton to predict the above-ground morphological indexes, square-boll abscission and LAI of cotton. These models were tested with the field experimental data collected from different sits. The main results are as follows:1. Effects of temperature-light factor on the above-ground morphological index and square-boll abscission in cottonA test was carried out with three sowing dates to study the effects of temperature-light factor on the above-ground morphological indexes and square-boll abscission of cotton. Cumulative thermal and solar radiative effectiveness (TSE) integrating independent thermal and solar radiative effectiveness and their interaction was introduced as the driving variable. The dynamics of the height of plant, the number of fruit branches, fruit nodes, big bolls with TSE were generally best described by logistic curves, while the changes of the number of squares and young bolls followed quadratic curves. The termination of the fastest growth or occurrence were about73,80,80and104, respectively for the height of plant(HP), the number of fruit branches(NFB), fruit nodes(NFN) and big bolls(NBB). The appearance of the biggest relative growth or occurrence rate were about46,57,65and89. respectively for HP, NFB, NFN and NBB. And their theoretical maximums were about132cm,22,83, and25per plant. There was a positive correlation between the biggest relative growth or occurrence rate and their initial TSE. For the number of squares(NCS) and young bolls(NYB), their theoretical maximums were about27and9per plant, whose TSE were about68and85.2. Simulating the effects of nitrogen on the above-ground morphological index and square-boll Abscission in cottonNitrogen, the most important crop nutrient, has a regulatory role in crop growth. In order to support nutrient management in main morphogenetic processes of cotton, a simple model was presented to simulate the effects of nitrogen on the above-ground morphological indexes and abscission of cotton. A nitrogen test was carried out with six nitrogen application levels to study the quantitative relationship between nitrogen concentration in subtending leaf of lower fruit branches (NCSLL) and morphological indexes at flowering and boll-setting stage in cotton. Cumulative thermal and solar radiative effectiveness (TSE) integrating independent thermal and solar radiative effectiveness and their interaction was introduced as the driving variable. Results showed that the changes of NCSLL at flowering and boll-setting stage followed the equation:y=axb. The average NCSLL was approximately equal to the NCSLL of some day after anthesis and the ratio of the total number of days at flowering and boll-setting stage was stable. The dynamics of the height of plant, the number of fruit branches, fruit nodes, big bolls with TSE were generally best described by logistic curves, while the changes of the number of squares and young bolls followed quadratic curves. At the same time, the relationships between the model parameters of morphological indixes and the average NCSLL at flowering and boll-setting stage in cotton also followed quadratic curves. The model was validated using a data from an independent experiment with four N application rates and root mean squared error (RMSE) was used for assessing the model performance. Validation of the model resulted in RMSE values of3.4cm,1.1,2.7,2.4,1.6,1.4and3.5%per plant, respectively for the height of plant, the number of fruit branches, fruit nodes, squares, young bolls, big bolls, and the abscission rate. This indicated that the simulated and observed values were inosculated well. Under different planting density conditions, the RMSE were7.3cm,1.2, 3.1,2.4,1.7,1.6and4.0%per plant, respectively. So the simulated and observed values were also agreed well except plant height’s.3. Effects of short waterlogging at flowering and boll-setting stage on above-ground morphological index and square-boll abscission in cottonBy setting the short waterlogging for3days,6days,9days and12days at flowering and boll-setting stage test, and TSE including RTE (relative thermal effect) and SRE (solar radiative effect) for the driving variable, the study analyzes quantitatively the dynamic effects of the dawn water potential of functional leaf at the end of different waterlogging treatments on the height of plant, the number of fruit branches, fruit nodes, squares, young bolls, big bolls, and the abscission rate to construct the model. The results show that the dawn water potential of functional leaf have a linear decrease relationship with longer waterlogging, which has a quantitative relation with the model parameters of morphological indexes. The average RMSE between the simulated and observed values of the height of plant, the number of fruit branches, fruit nodes, squares, young bolls, big bolls, and the abscission rate were2.6cm,1.3,2.3,1.9,1.7,2.0and4.7%per plant, respectively. The simulated and observed values were inosculated well, indicating that this model was good in prediction to the height of plant, the number of fruit branches, fruit nodes, squares, young bolls, big bolls, and the abscission rate after waterlogging.4. Studying the simulation models on the above-ground morphological index, square-boll abscission and LAI in cottonBased on the effects of temperature-light factor, nitrogen and waterlogging on the above-ground morphological indexes, square-boll abscission and LAI of cotton in the former three chapters, introducing genetic effect and cumulative physiological, thermal and solar radiative effectiveness (TVE) as the driving variable is to simulate LAI and construct simulation model of cotton which can be used to simulate the dynamics of HP, NFB, NFN, NBB, NCS, NYB and abscission rate of different varieties under different conditions. Besides, using independent tests to validate the model. Validation of the model resulted in RMSE values of2.7cm,1.1,2.6,2.3,1.7,1.7and5.1%per plant, respectively for the height of plant, the number of fruit branches, fruit nodes, squares, young bolls, big bolls, and the abscission rate. In addition, the RMSE of LAI was0.29. This indicated that all the simulated and observed values were inosculated well.