Genetic Diversity of Rapeseed Accessions from Different Geographic Locations Revealed by Expressed Sequence Tag‐Simple Sequence Repeat and Random Amplified Polymorphic DNA Markers

Abstract

Genetic diversity information will be very valuable for future rapeseed {Brassica napus L.) improvement. The genetic diversity and relationships among 92 rapeseed accessions, including 44 from China, 22 from Europe, 16 from the United States, and 10 fronn Canada, were assessed by 60 random amplified polymorphic DNA (RAPD) and 22 expressed sequence tag (EST)-simple sequence repeat (SSR) primers. In total, 618 RAPD and 117 EST-SSR polymorphic fragments were detected. The average number of polymorphic fragments found by each RAPD primer was 10.3 ranging from 3 to 17 and that detected by each pair of EST-SSR primer was 5.3 ranging from 4 to 7. The unweighted pair-group method with arithmetic mean (UPGMA) cluster analysis revealed that these 92 accessions could be classified into three major clusters. Cluster I consisted of accessions mainly from China, which belong to the semi-winter type. Cluster II contained accessions from Europe and the United States, which belong to the winter type. Cluster III was a semi-winter and spring type mixture group, which contained accessions mainly from China and Canada. The principal component analysis and population structure analysis revealed similar results to the cluster analysis. Analysis of molecular variance result based on four geographic groups indicated that genetic variation was 8.24% among populations of geographic regions and 91.76% within geographic regions. Rapeseed accessions from the United Stated have the greatest genetic distance from accessions of other geographic origins, especially those from China. United States rapeseed could be important germplasm resources for enriching the genetic background of Chinese rapeseed and vice versa.

Genetic Diversity and Population Structure in a World Collection of Brassica napus Accessions with Emphasis on South Korea, Japan, and Pakistan

“…Analysis of molecular variance showed that only 9% of the variation was accounted for by the seven populations whereas 91% was due to variation among individual B. napus lines. The overall genetic differentiation among populations was also low (ΦPT = 0.09), which is in agreement with previous findings by Li et al (2012). Nevertheless, we found that the pairwise genetic differentiation were significantly higher (ΦPT = 0.20 to 0.26) between the Canadian and Australian spring types and the Chinese and Pakistani semiwinter type accessions than comparisons between other populations.…”

“…The overall genetic differentiation among populations was also low (ΦPT = 0.09), which is in agreement with previous findings by Li et al (2012). The overall genetic differentiation among populations was also low (ΦPT = 0.09), which is in agreement with previous findings by Li et al (2012).…”

“…The majority of research in B. napus has been performed with simple sequence repeat (SSR) markers (Bus et al, 2011;Chen et al, 2008;Hasan et al, 2006;Li et al, 2012;Soengas et al, 2006;Wang et al, 2009;Zhou et al, 2006), but restriction fragment length polymorphism (Diers et al, 1996), randomly amplified polymorphic DNA (Cartea et al, 2005), and amplified fragment length polymorphism (AFLP) (Lombard et al, 2000;Qian et al, 2006) markers have also been used. The majority of research in B. napus has been performed with simple sequence repeat (SSR) markers (Bus et al, 2011;Chen et al, 2008;Hasan et al, 2006;Li et al, 2012;Soengas et al, 2006;Wang et al, 2009;Zhou et al, 2006), but restriction fragment length polymorphism (Diers et al, 1996), randomly amplified polymorphic DNA (Cartea et al, 2005), and amplified fragment length polymorphism (AFLP) (Lombard et al, 2000;Qian et al, 2006) markers have also been used.…”

“…Polymorphism in genomic DNA is commonly used to assess genetic diversity in both plant and animal species. The majority of research in B. napus has been performed with simple sequence repeat (SSR) markers (Bus et al, 2011;Chen et al, 2008;Hasan et al, 2006;Li et al, 2012;Soengas et al, 2006;Wang et al, 2009;Zhou et al, 2006), but restriction fragment length polymorphism (Diers et al, 1996), randomly amplified polymorphic DNA (Cartea et al, 2005), and amplified fragment length polymorphism (AFLP) (Lombard et al, 2000;Qian et al, 2006) markers have also been used. These studies have shown that population structure in oilseed rape is primarily based on spring, semiwinter, and winter growth habits (Chen et al, 2008;Li et al, 2012;Qian et al, 2006;Zhou et al, 2006) as well as morphology in leaf and root crops when these were included in the analysis (Bus et al, 2011;Cartea et al, 2005;Hasan et al, 2006;Soengas et al, 2006).…”

Heterotic Grouping and the Heterotic Pattern among Chinese Rapeseed (Brassica napus L.) Accessions

“…Chinese breeders developed most cultivars of oilseed rape that were adapted to local conditions by interspecific hybridization between the introduced B. napus and the indigenous B. rapa cultivars (Qian et al, 2006). As a result, Chinese rapeseed became genetically diverse from winter and spring rapeseed from other regions of the world (Becker et al, 1995; Diers and Osborn, 1994; Li et al, 2012; Ma et al, 2000; Qian et al, 2006). In addition, because of different local B. rapa accessions used in breeding programs (Liu, 2000, p. 26‐45; Qian et al, 2006), there is considerable genetic variation among Chinese B. napus .…”