Modeling Demographics and Genetic Diversity in Ex Situ Collections during Seed Storage and Regeneration

• Published in: Crop science Vol. 50; no. 6; pp. 2440 - 2447
• Main Authors: Richards, Christopher M, Lockwood, Dale R, Volk, Gayle M, Walters, Christina
• Format: Journal Article
• Language: English
• Published: Madison Crop Science Society of America 01.11.2010; American Society of Agronomy
• Subjects: Agronomy. Soil science and plant productions; alleles; Biological and medical sciences; Collections; crops; Cultivars; Frequency distribution; Fundamental and applied biological sciences. Psychology; Gene banks; Generalities. Genetics. Plant material; Genetic diversity; genetic erosion; Genetic resources, diversity; genetic variation; Genetics and breeding of economic plants; genotype; Genotypes; heterozygosity; inbreeding; Kinetics; mortality; outcrossing; plant breeding; plant genetic resources; Plant material; sampling; seed aging; seed germination; seed storage; Seeds; simulation models; storage time; viability; wild plants; Regeneration; Genetic diversity; Demography; Storage; Modeling
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2010.04.0236

Gene banks have a critical role in preserving genetic diversity for many conservation uses. A key challenge in this task is maintaining both the genetic integrity and the viability of a collection during regeneration and long-term storage. In this study we examine the interacting effects of sampling and viability decline from seed aging on genetic diversity. To do this, we developed a model that simulates sampling during regeneration of individual genotypes using two commonly used but contrasting regeneration protocols. Critically, the model simulates a realistic nonlinear decline in viability across time, and the combined effects of sampling and mortality were evaluated for their effect on allelic diversity. In addition, the model was used to contrast the kinetics of allelic richness among rounds of regeneration in accessions with different heterozygosity levels (e.g., cultivars vs. wild) and different breeding systems (outcrossing vs. inbred). Results underscore a significant interaction between regeneration timing and regeneration size. Regeneration procedures should consider viability kinetics and intra-accession diversity to best manage genetic erosion. These changes highlight the trade-off faced by curators between the logistics of increasing regeneration sampling size and improving the technical procedures for seed storage and monitoring.