Abstract

Global climate change that results in the increased global temperatures is known as the directional effect on several growth stages of rice. The aim of this study was to compare the Growing Degree Day (GDD) of rice RD49 at several growth stages of rice (seedling, tillering, the highest-tillering, panicle initiation, flowing, physiological maturity and harvest stage) between the field and greenhouse condition. An experiment was performed by collecting the highest and lowest temperature of the day from paddy field condition at Snabtub sub-district, Wang Noi distrist, Ayutthaya province and from greenhouse condition at Department of Agronomy, Kasetsart University which were used for GDD values calculation. Comparison of the calculated GDD values obtained from field and greenhouse was then performed. The results showed that the accumulated GDD values of tillering stage (2 weeks after planting) of field and greenhouse condition were 306.83 and 329.23 °d, respectively. The accumulated GDD values of panicle initiation (10 weeks after planting) of field and greenhouse condition were 1,533.30 and 1,489.98 °d, respectively. The number of tillers per plant under field condition was 2.37 tillers per plant, which was lower than greenhouse condition (6.5 tillers per plant). The numbers of panicle under field condition were 3.75 panicles per plant. Alternatively, there was no the panicle initiation under greenhouse condition. The accumulated GDD values of harvest stage (14 weeks after planting) of field and greenhouse condition were 2,106.65 and 2,033.48 °d, respectively. Collectively, an assessment of rice growth by using GDD value can be used for prediction several growth stages of rice RD49, which will be useful for the rice cultivation management.