ESTIMATION OF OPTIMUM PLOT SIZE, NUMBER OF REPLICATIONS AND NUMBER OF SAMPLING UNITS FOR FABA BEAN YIELD TRIALS | ||
| Journal of Plant Production | ||
| Article 3, Volume 29, Issue 8, August 2004, Pages 4375-4390 PDF (3.92 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jpp.2004.238781 | ||
| Authors | ||
| Manal M. Salem,; Somaia A. Barakat | ||
| Central Laboratory for Design and Statistical Analysis, Agricultural Research Center, Giza, Egypt. | ||
| Abstract | ||
| This investigation was undertaken to study the optimum plot size, number of replications and number of sampling units for faba bean yield trials at Sids Agric. Research Station during 2002/2003 and 2003/2004 seasons. The experiment included 7 genotypes of faba bean cultivars. A randomized complete block design with three replications was selected. The area of each plot was 7.2 m2• Data were subjected by two procedures, the first method was developed by Smith (1938) and the second method was the maximum curvature developed by Lessman and Atkins (1963). The results obtained could be summarized as follows: Increasing plot size decreased the variance per basic unit and the coefficient of variability. However, the reduction was not in proportion with the increase in plot size. The index of soil variability ranged from -0.512 to -0.807 with an average of - 0.660 The exponential relationships between the coefficient of variability (C.v.) and plot size (X) were: C.v.= 18.293 X-O.624 for the first season. C.v.= 16.318 X-0.860 for the second season. • The optimum plot size was resulted by two methods as follows: 1- Smith's method: The optimum plot size was 2.441 and 3.218 m2 in the first and second seasons, respectively. 11- Maximum curvature method: The optimum plot size was 13.342 and 17.648 m2 in the first and second seasons, respectively. Increasing plot size and/or number of replications reduced the magnitude of difference detected at specified level of significance. The reduction of difference with increasing plot size was less than that obtained by equivalent increase in the number of replications. The standard error for the studied characters decreased as number of sample units or replicates increased. Number of plants required to detect 10% change between means were markedly decreased as number of replicates increased. The optimum number of sample units differed from character to another and it was greatly affected by number of replications. | ||
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