Climate change and variability (CCV) exposes tropical crops as rice to heat and drought. Increasing atmospheric CO2 is expected to improve plant transpiration efficiency but benefits may be more than offset by reduced transpirational cooling and accelerated phenology. Yield is generally affected by environment effects on morphogenesis, particularly to stress during reproductive sink capacity determination. Exposure of reproductive processes to heat and drought, in turn, depends on plant structura1 development and resulting microclimate and water availability. These highly genotype-dependent interactions make it difficulty to predict CCV impacts and design adaptations. An important step is to model this system, particularly interactions between plant morphogenetic and phenological processes with climate and resources, and resulting microclimate within the crop stand. Models are needed that consider crop structura1 development at organ level, while providing sufficient phenological and physiological detail to situate stress sensitive processes within time and canopy. Such a model must be coupled with a heat balance providing accurate information on soil, floodwater, leaf and panicle temperature. Key physiological processes would thus become predictable, including: tillering and tiller maintenance/abortion, leaf area dynamics including senescence, spike number dimensioning and adjustments, stem carbohydrate accumulation and mobilization to grains, thermal and drought induced spike sterility determined at the sensitive microspore and anthesis stages or by panicle exertion limitation, and finally grain filling process. A new type of functional-structura1 plant models is needed that integrates environment dynamics within soil-water-plant-atmosphere continuum. EcoMeristem model was designed to simulate environment and genotype driven phenotypic plasticity for rice and other cereals. It simulates rice plant morphogenesis at organ, plant and canopy levels in response to drou