Response of Thai rice varieties under elevated CO2 concentrations

Seeds of rice will be germinated in a plate by adding water and 7 days after germination, three germinated seeds will be transferred to plastic pots (38 cm top, 24 cm bottom and 27 cm height). The pots will be placed in a solar plant factory greenhouse at National Center for Genetic Engineering and Biotechnology. The soil type that will be used in this experiment has a clay form (65.7% clay, 23.3% silt, and 11.0% sand). Each pot will contain 15 kg of soil. Weeds will be manually controlled and Fertilizer formulas 16-8-2 and 46-0-0 will be mixed and applied at a rate of 1 g/pot (0.31 g N, 0.04 g P and 0.01 g K) at 18 and 32 DAS. The seedlings will be thinned to one seedling per pot at 20 days after seeding (DAS). At 30 DAS, plants were treated with CO2 at two levels, 400 ppm representing ambient concentration and 800 ppm for elevated CO2 concentration. Treatment for elevated concentration of CO2 will be conducted in a solar plant factory climate-controlled greenhouse equipped with temperature and humidity controls and sensors to monitor microclimate (temperature, humidity, radiation). A total of 50 pots per CO2 concentration including border pots will be arranged at 20-cm spacing among plants in a completely randomized design with five replications per cultivar and per CO2 treatment. Pots will be kept watered at field capacity while maintaining 5 cm of standing water.