Abstract

Because of labor shortage farmers in the central region grow rice by using wet broad cast method accounted for 45.10 percent, of total cultivated areas. Famers use planting rate of 28.62 kg/rai, which is higher than the recommended rate of the Department of Rice As a result, the rice plot has a large error density, Which is difficult in farm management, and obtains low yield rice The objective of this study is to determine the influence of planting rates on chlorophyll content, leaf area and dry weight accumulation at various growth stages of RD49 rice variety. The experiment was conducted at the farmer's plots in Sanabtub sub district, Wang Noi district, Phra Nakhon Si Ayutthaya province by using Randomized Complete Block Design (RCBD) with 4 replications. The treatments were: three seeding rates; 7.5 kg/rai; 15 kg/rai, 25 kg/rai. The results showed that planting rate Influence total chlorophyll content during bloom stage planting with seed rate of 7.5 and 25 kg/rai provided higher in leaf area index compared to planting with seed rate of 15 kg/rai. the growth rate during panicle stage from planting by seed rate at 15 kg/rai. was higher than those of the other 2 planting rates. Additionally, Leaf area index during panicle stage correlates to yield, which the highest yield was obtained from planting rate of 7.5 kg/rai. at the seed rate of 7.5 kg/rai, yielding the highest yield per area. which explains that seed rate affects stems growth and growth in the production phase which must be managed.