Abstract
A case study survey on yield and its components in the Central Plain of Thailand was conducted in the Saraburi-Ayutthaya area during the harvesting season of 1967. The average values of yield components of the thirty plots of this study were compared with those of other surveys done in Thailand and Malaya. Basing on these data an attempt to figure out the yield components of rice plants actually grown by farmers in southeast Asian countries was made. Simple correlation coefficients among yield components were also calculated and compared for the results of several surveys including this one. However, no general rule of correlation coefficients common for southeast Asia was found. All the yield components of the samples were presented graphically. According to the shapes of the yield component patterns of each sample on this graph, the thirty samples were grouped into six types. Their characteristics were discussed.
