HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Helms, T. C. Articles by Hammond, J. J. Search for Related Content PubMed Articles by Helms, T. C. Articles by Hammond, J. J. Agricola Articles by Helms, T. C. Articles by Hammond, J. J.

Intrablock Variance among Duplicate Treatments for Nearest-Neighbor Analyses

Dep. of Plant Sciences, North Dakota State Univ., Fargo, ND 58105
Dep. of Plant Sciences, South Dakota State Univ., Brookings, SD 57007
Dep. of Plant Sciences, North Dakota State Univ., Fargo, ND 58105

^* Corresponding author (helms{at}badlands.nodak.edu).

Nearest-neighbor analysis (NNA) adjusts for spatially correlated residuals, with the goal of increasing precision. The magnitude of the block x treatment interaction mean square is commonly used to evaluate the precision of the NNA model. An alternative method of evaluating the precision of the NNA and classical unadjusted (UNADJ) randomized complete block (RCB) analysis would be to use the pooled variance between duplicate treatments within each block. We defined pure error as variation between plots that are treated alike within a block. Within each location, each genotype was randomly assigned to two plots within each block of an RCB design. The pure error of soybean [Glycine mar (L.) Merr.] genotypes was evaluated at eight locations. Our objective was to compare the block x treatment and pure error mean squares for yield, physiological maturity, and plant height to determine whether the NNA or UNADJ analysis reduces intrablock variation. The NNA analysis always decreased the magnitude of the block x treatment interaction mean squares, compared with the UNADJ analysis. In some comparisons, the pure error mean square of the NNA analysis was significantly smaller than the pure error of the UNADJ analysis. The magnitude of the block x treatment mean square is not useful for comparing the relative precision of these two analyses. When the pure error mean square was used to measure precision, the NNA was at least as precise as the UNADJ analysis.

Received for publication May 5, 1997.

This article has been cited by other articles:

				R.-C. Yang, T. Z. Ye, S. F. Blade, and M. Bandara Efficiency of Spatial Analyses of Field Pea Variety Trials Crop Sci., January 1, 2004; 44(1): 49 - 55. [Abstract] [Full Text] [PDF]

				M. Bermudez and A. P. Mallarino Yield and Early Growth Responses to Starter Fertilizer in No-Till Corn Assessed with Precision Agriculture Technologies Agron. J., September 1, 2002; 94(5): 1024 - 1033. [Abstract] [Full Text] [PDF]

				T. C. Helms, J. H. Orf, and J. T. Terpstra Resource Allocation to Select for Yield in Soybean Crop Sci., September 1, 2002; 42(5): 1493 - 1497. [Abstract] [Full Text] [PDF]