A Basic Study on Field Experiment and Investigation Methods in Rice Plant. III. Precision of some sampling methods in sample survey of quantitative characters.

Abstract

In sample survey on field experiment, samples have to be sampled at random in principle, but samples are often taken systematically due to restriction of time, labor and plot area. In order to get information on precision of the sampling methods in survey of quantitative characters in a hand-transplanted rice field, the error of some sampling methods were compared with that of random sampling. The characters surveyed were tiller number, panicle number and fresh weight both at maximum tiller number and full heading stage. The following sampling method was simple and precise at both growth stage, because its error was almost equal to the error of random sampling: split the experimental plot into four sub-plots by bisectors of length and width, then, sample continuous 10 hills in the direction of a planting row from two sub-plots located diagonally. At full heading stage, when CV of these characters were small, the other two sampling methods were also practical: (1)Sample continuous 20 hills in the direction of a planting row. (2)First, sample continuous 10 hills in the direction of a planting row, then change row to be sampled to the next one on the right or left side, then sample continuous 10 hills in the same direction.