Intra- and interplot variability of Heterodera glycines population densities in experimental settings to soybean variety evaluations in Nebraska

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• 作者：Oscar Pé ; rez-Herná ; ndez^a ; ^{perez-hernandez@ucmo.edu} ; Loren J. Giesler^b
• 关键词：Beta-binomial ; Correlogram ; Epidemiology ; Spatial pattern ; Cyst nematode ; Soybean variety evaluations ; Spatial variability
• 刊名：Crop Protection
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：94
• 期：Complete
• 页码：123-136
• 全文大小：878 K
• 卷排序：94

文摘

SCN incidence (number of SCN-positive soil cores out of 10 per plot) occurs in an aggregated pattern within plots, but such aggregation may become less apparent with an increase of the infestation level, tillage, and pathogen dispersal over relatively small distances (e.g. 1–4 m). The intra plot clustering of incidence suggests a varying probability of SCN cyst recovery within plots during sampling and an irregular pathogen pressure on soybean plants within plots. At the interplot scale, SCN population densities in plots are positively correlated with population densities in contiguous plots, and likely, with population densities in plots located up to two positions away. The aggregation of contiguous plots is manifested even when the SCN infestation levels across an entire experimental area are close to the SCN detection threshold. Altogether, this study suggests consideration of the spatial pattern in SCN-soybean variety evaluations, particularly, if rigorous comparisons among varieties are desired. The information generated herein can be useful to determine site suitability for a variety trial and help guide a better assignation of varieties to experimental units, for example, assigning varieties to experimental units (plots) that do not exhibit a spatial relationship in terms of SCN population densities.