The Estimation of Yield in Potato

[摘要] Four experiments were carried out in 1950 and 1956 with the purpose of determining the number of plants required for estimating the yield in potato. The variety used was Danshaku and the conditions of growing plants in the four experiments were as follows; Exp. A : Perfect tubers planted, each tuber 37-56g weighing, 1 stem per hill, upland field, 840 plants measured, 1956. Exp. B : Longitudinally half-cut tubers planted, each 37-56g weighing, 1 stem per hill, upland field, 1160 plants measured, 1956. Exp. C : Random-cut tubers planted, each less than 37g weighing, 1 stem per hill, upland field, 1200 plants measured, 1956. Exp. D : Half-cut and perfect tubers mixed-planted, each 37-56g weighing, 3 stems per hill, the second crop in the paddy field, 1600 plants measured, 1950. The yield and number of tubers per hill were recorded when the plants came to maturity. On the basis of these records the numbers of plants required for estimating the mean yield and mean number of tubers were calculated by the formula n=s2t2/()2 (n=sample size; t=Student's t-value ; x^-=sample mean; m = population mean) for various reliabilities (Table 1). The calculation was made in 5 different ways, i. e., on the individual basis and group mean bases of 5, 10, 20 and 40 plants taken together along the row. The numbers of plants to be sampled thus obtained for each level ofgroup ‥ng were almost the same in all experiments, excepting Exp. A which suffered from the late blight disease and gave a large coefficient of variability. From these results it was concluded that the most practical method for estimating the total yield or total numder of tubers is as the first step to take a random sample of about 50 groups of 5 plants or about 30 groups of 10 plants from a field and then to multiply their mean by the totalnumber of plants grown in the field.

[学科分类] 农业科学（综合）