| While quantitative trait loci (QTL) analysis of yield-related traits for rice has been rapidly developing, crop models using genotype information have been proposed only relatively recently. In this study, a 3D functional-structural plant model (FSPM) of rice is presented, which integrates the morphology (plant structure, static and dynamic), important physiological processes (functions) and quantitative genetic information for plant height. It was devised using GroIMP, an interactive modeling platform based on the Relational Growth Grammar formalism (RGG) and the extended L-systems (XL) modeling language, which is a superset of Java.This dissertation consists of six chapters:Chapter 1 is an overall introduction, including:general background of the crop models and FSPM methods; a literature review on quantitative genetics of rice (Oryza sativa L.). general use of plant models and, more specifically, functional-structural plant modeling, a brief introduction of the XL language and of GroIMP; finally challenges and preliminary conclusions.In Chapter 2, a basic phenotype model of rice implemented as a relational growth grammar in GroIMP is presented. This model simulates growth and morphology in combination with ecophysiological processes using the FSPM paradigm, thereby integrating rules for morphogenesis (organ formation, growth and organ extension) and physiological functions (photosynthesis, source-sink functions etc.) with each other. First simulation results including final morphology and performance of the photosynthesis model are discussed.Chapter 3 discusses an extension of the rice FSPM. which now considers ecophysiological processes, morphogenesis, and quantitative genetics. In the model, some parameters of the growth function are controlled by genetic models describing the effect of main effect and epistatic QTLs. The link between the phenotype (as represented by the simulated rice plant), and the QTL genotype was implemented via a data interface between the rice FSPM and the QTLNetwork software, which computes predictions of QTLs from map and measured trait data. At the example of the traits plant height and grain yield, it is shown how QTL information for a given trait can be used in an FSPM, computing and visualizing the phenotypes of different lines of a mapping population. Further, we demonstrate how modification of a particular trait feeds back on the entire plant phenotype via physiological processes considered.In Chapter 4, a method for the coupling of QTLs with an ecophysiological model and modifications for the sexual reproduction of genotypes are described, and a virtual breeding model of rice called "RiceBreeder" is presented. As an implementation and validation of the genotype-phenotype model of rice, it is used to visualize the superior lines as well as the parental lines from a mapping population, representing the various growth dynamics. As a validation QTL mapping results from the simulated phenotype are compared with the measured parameters.Chapter 5 is a general discussion for the previous chapters. A rice FSPM that integrates selected physiological processes, morphological aspects and quantitative genetics for yield-related traits by implementing a detailed description of organogenesis, morphogenesis and growth dynamics is developed. It is thus used to employ QTL information to refine model parameters and visualize the dynamics of development of the entire phenotype as a result of ecophysiological processes, including the trait(s) for which genetic information is available. The development of the RiceBreeder model will accelerate the progress in developing "breeder's tool" for breeders and scientists with further extensions.Some conclusions are drawn in Chapter 6:FSPM as a new paradigm in plant modeling will play an important role in the assessment of plant performance of variation in genetic traits across environments; and the current rice model will ultimately become a powerful tool for a better understanding of plant biology and crop breeding.
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