Title
Scheduling Viability Tests for Seeds in Long-Term Storage Based on a Bayesian Multi-Level Model
Document Type
Article
Publication Date
6-2012
Journal or Book Title
Journal of Agricultural, Biological, and Environmental Statistics
Volume
17
Issue
2
First Page
192
Last Page
208
DOI
10.1007/s13253-012-0085-y
Abstract
Genebank managers conduct viability tests on stored seeds so they can replace lots that have viability near a critical threshold, such as 50 or 85 % germination. Currently, these tests are typically scheduled at uniform intervals; testing every 5 years is common. A manager needs to balance the cost of an additional test against the possibility of losing a seed lot due to late retesting. We developed a data-informed method to schedule viability tests for a collection of 2,833 maize seed lots with 3 to 7 completed viability tests per lot. Given these historical data reporting on seed viability at arbitrary times, we fit a hierarchical Bayesian seed-viability model with random seed lot specific coefficients. The posterior distribution of the predicted time to cross below a critical threshold was estimated for each seed lot. We recommend a predicted quantile as a retest time, chosen to balance the importance of catching quickly decaying lots against the cost of premature tests. The method can be used with any seed-viability model; we focused on two, the Avrami viability curve and a quadratic curve that accounts for seed after-ripening. After fitting both models, we found that the quadratic curve gave more plausible predictions than did the Avrami curve. Also, a receiver operating characteristic (ROC) curve analysis and a follow-up test demonstrated that a 0.05 quantile yields reasonable predictions.
Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Language
en
File Format
application/pdf
Recommended Citation
Trapp, Allan II; Dixon, Philip M.; Widrlechner, Mark P.; and Kovach, David A., "Scheduling Viability Tests for Seeds in Long-Term Storage Based on a Bayesian Multi-Level Model" (2012). NCRPIS Publications and Papers. 30.
https://lib.dr.iastate.edu/ncrpis_pubs/30
Included in
Agricultural Science Commons, Agriculture Commons, Biostatistics Commons, Horticulture Commons
Comments
This article is from Journal of Agricultural, Biological, and Environmental Statistics 17, no. 2 (June 2012): 192–208, doi: 10.1007/s13253-012-0085-y.