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A process model for explaining genotypic and environmental variation in growth and yield of rice based on measured plant N accumulation
- Yoshida, Hiroe, Horie, Takeshi
- Field crops research 2009 v.113 no.3 pp. 227-237
- Oryza sativa, rice, plant growth, grain yield, nitrogen, plant nutrition, nutrient uptake, genetic variation, environmental factors, genotype-environment interaction, mechanistic models, calibration, model validation, leaf area index, nutrient partitioning, vegetative growth, dry matter accumulation, inflorescences, photosynthesis, nutrient use efficiency, stomatal conductance, senescence
- The objective of this study was to develop a mechanistic model for simulating the genotypic and environmental variation in rice growth and yield based on measured plant N accumulation. The model calibrations and evaluations were conducted for rice growth and yield data obtained from a cross-locational experiment on 9 genotypes at 7 climatically different locations in Asia. The rough dry grain yield measured in the experiment ranged from 71 to 1044gm⁻² over the genotypes and locations. An entire process model was developed by integrating sub-models for simulating the processes of leaf area index development, partitioning of nitrogen within plant organs, vegetative biomass growth, spikelet number determination, and yield. The entire process model considered down-regulation of photosynthesis caused by limited capacity for end-product utilization in growing sink organs by representing canopy photosynthetic rate as a function of sugar content per unit leaf nitrogen content. The model well explained the observed genotypic and environmental variation in the dynamics of above-ground biomass growth (for validation dataset, R ² =95), leaf area index development (R ² =0.82) and leaf N content (R ² =0.85), and spikelet number per unit area (R ² =0.67) and rough grain yield (R ² =0.66), simultaneously. The model calibrations for each sub-model and the entire process model against observed data identified 10 genotype-specific model parameters as important traits for determining genotypic differences in the growth attributes. Out of the 10 parameters, 5 were related to the processes of phenological development and spikelet sterility, considered to be major determinants of genotypic adaptability to climate. The other 5 parameters of stomatal conductance, radiation extinction coefficient, nitrogen use efficiency in spikelet differentiation, critical leaf N causing senescence, and potential single grain mass had significant influence on the yield potential of genotypes under given climate conditions.