Maliheh Arab, Preventative Gynecology Research Center (PGRC
), Imam Hossein Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
juncea obtained from Plant Genetic Resource Centre (PGRC), Gannoruwa, Sri Lanka.
Although there are over sixty mustard (Brassica juncea (L.) Czern & Coss) germplasm accessions are present in the gene bank of PGRC  in Sri Lanka, genetic diversity and the relationship among these accessions have yet to be studied fully.
For eight cultivars, information about the mucilage was available from a preliminary screening conducted by PGRC in 1999.
The flax seed used for screening of the world collection originated from 1689 flax accessions regenerated during one of the years 1999-2001 by PGRC at Saskatoon (Diederichsen et al., 2002).
The objective of this analysis was to assess the geographic patterns of RAPD variation in the world collection of cultivated flax maintained at PGRC. Molecular markers are less affected by environmental factors than those morphological and botanical characters previously used to describe flax variation and should be more informative in determining geographic patterns of flax diversity (Harlan, 1986).
The PGRC collection of flax germplasm is largely a duplication of the flax collection maintained in the United States National Plant Germplasm System.
Approximately 10 to 15 seeds of each cultivar were randomly selected from the accession in the PGRC oat collection and grown in the greenhouse at the AAFC Saskatoon Research Centre.
Abbreviations: bp, base pair; AFLP, amplified fragment length polymorphism; PCR, polymerase chain reaction; PGRC, Plant Gene Resources of Canada; SSR, simple sequence repeat.
The RAPD characterization procedures used were the same as those previously applied for all the flax accessions held at PGRC and include seed planting in greenhouse, extraction of DNA from young leaves, PCR analysis of isolated DNAs using RAPD primers, and scoring of DNA fingerprints (Fu et al., 2002a).
This average proportion of fixed loci was lower than those observed for all of the other cultivars in the PGRC collection (51.2% including fiber flax cultivars), higher than those for the flax landrace accessions assessed (42.7%), and comparable with those for the whole flax collection (45.8%; Fu et al., 2002a; Fu et al., unpublished).
Origin Heading Plant Flag leaf Spike group date height blade area length UM 39 15 26 12 PGRC
40 13 24 12 USDA-MO 38 15 19 13 CA-Jenkins 28 17 22 15 USDA-NSGC 33 17 - 17 USDA-OR 9 17 23 9 CA-Davis is 37 15 19 11 CIMMYT 26 14 13 13 Whole collection 46 19 22 14 Origin Spikelet Kernel Kernel group no./spike no./spike no./spikelet UM 12 43 41 PGRC
14 26 22 USDA-MO 11 33 31 CA-Jenkins 11 22 22 USDA-NSGC 20 45 41 USDA-OR 11 22 24 CA-Davis is 11 19 19 CIMMYT 13 17 17 Whole collection 15 34 35 Origin Spike group density Mean UM 13 25 PGRC
11 20 USDA-MO 15 22 CA-Jenkins 16 19 USDA-NSGC 22 28 USDA-OR 11 16 CA-Davis is 9 17 CIMMYT 8 15 Whole collection 15 25