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Applications of bulking in molecular characterization of plant germplasm: a critical review

Published online by Cambridge University Press:  27 June 2007

Yong-Bi Fu*
Plant Gene Resources of Canada, AAFC Saskatoon Research Centre, 107 Science Place, Saskatoon, SK S7N0X2, Canada
*Corresponding author. E-mail:


Characterization of plant germplasm using molecular techniques is playing an increasingly important role in the management and utilization of plant genetic resources, but has its limitations in the screening of large numbers of accessions held in seed genebanks worldwide. Bulking individual plants from one accession or group to form a representative sample is a promising approach to widening the scope of a characterization, but it is not without technical problems in detecting genetic variation. This review was conducted to assess the technical pitfalls of bulking, and to evaluate the effectiveness of various bulking methods in the assessment of genetic variation and genetic relationships, and in the identification of plant germplasm. Clearly, some alleles, particularly those occurring at low frequency, may go undetected in a bulked sample, depending on the bulking methods and the molecular techniques used. As a result, genetic diversity estimates and genetic relationship inferences can be significantly biased. Germplasm identification may not be always reliable. Thus, it is imperative that the detection limit imposed by bulking be assessed for a newly initiated molecular germplasm characterization and bias be considered in interpretation of the resulting characterization data. Equally imperative is the need for continuous efforts of exploring efficient bulking procedures for the screening of large germplasm collections, particularly by the newly developed marker systems.

Research Article
Copyright © NIAB 2003

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