The genetic diversity of UK, US and Australian cultivars of Triticum aestivum measured by DArT markers and considered by genome

Abstract

The genetic diversity of UK, US and Australian wheat varieties over the period of modern plant breeding is estimated using diversity array technology markers. Diversity is assessed by both genetic distance between varieties, by AMOVA and as the volumes of multi-dimensional convex hulls estimated from principal co-ordinate analysis. At the whole genome level the three populations are genetically distinct; this is also true of the B genome. However, the US and Australian D genomes are found to occupy the same region of diversity space and the A genomes for these countries are partially overlapping. The use of high-density genotyping with a common marker set allows an unprecedented direct comparison between the diversities of the national populations, between individual genomes and the fluctuation of diversity over time. The highest genetic diversity amongst varieties is reported in the Australian population followed by the US, which in turn is more diverse than the UK. However the average diversity of loci is higher in the US set than in the Australian. Non-random fluctuations in genetic diversity over time are observed.

Molecular analysis of temporal genetic structuring in pea (Pisum sativum L.) cultivars bred in the Czech Republic and in former Czechoslovakia since the mid-20th century

“…Results from published studies vary considerably. Some studies showed a decrease in diversity over time (Russell et al 2000;Fu et al 2003;Reif et al 2005;Figliuolo et al 2007;Malysheva-Otto et al 2007,), while others observed increases (Fu 2006;White et al 2008) or a decrease in the diversity levels after which an increase occurred (Roussel et al 2004;Qi et al 2006). Our findings are consistent with the work of Le Clerc et al (2006) analysing changes in the pea germplasm genetic diversity through time.…”

Array-based high-throughput DNA markers for crop improvement

“…Later, barley and other crops having more complex genomes were also used ; also see Table 3). As evident from Table 3, DArT markers have been developed now on large scale (for instance, in wheat 43000 markers) and were extensively utilized for the study of genetic diversity, preparation of integrated framework linkage maps and association mapping (White et al, 2008). DArT markers have also been used for QTL mapping for Fusarium head blight in wheat and for leaf pubescence in barley (Rheault et al, 2007;Wenzl et al, 2007a).…”

“…Constructed a framework linkage map of 93 DH lines using DArT, AFLP and SSR markers. Inferred origin of DArT markers from gene-rich regions Semagn et al (2006) Used 41000 DArT markers and developed a linkage map with 90 SSR and 543 DArT (278 bread wheat-derived probes and 265 durum wheat probes) markers using 176 RILs Wenzl et al (2007b) 242 DArT markers were used to study association with resistance against stem rust, leaf rust, yellow rust, powdery mildew, yield and yield-contributing traits Crossa et al (2007) Studied genetic diversity of UK, US and Australian wheat varieties using DArT markers White et al (2008) Cassava 734 Tested three complexity reduction methods to select the two that generated largest frequency of polymorphic clones (PstI/TaqI: 14.6%, PstI/BstNI: 17.2%) to produce large genotyping arrays. Detected B1000 polymorphic clones on two arrays; PstI/TaqI array was validated using 38 accessions …”

Development of a molecular linkage map of pearl millet integrating DArT and SSR markers

“…The cost of DArT markers per data point has been reported to be tenfold lower than the cost of SSRs ). This genotyping method was developed originally for rice (Jaccoud et al 2001) and has subsequently been used in genetic mapping and fingerprinting studies in many other plants including barley (Wenzl et al 2004Hearnden et al 2007), cassava Hurtado et al 2008), Arabidopsis (Wittenberg et al 2005), pigeonpea , wheat (Akbari et al 2006;Crossa et al 2007;White et al 2008;Neumann et al 2010), sorghum (Mace et al 2008), the Festuca -Lolium complex (Kopecký et al 2009), Musa (Risterucci et al 2009; Amorim et al 2009), oat (Tinker et al 2009) and rye (Bolibok-Bragoszewska et al…”