Evaluating the Genetic Diversity of Triticale with Wheat and Rye SSR Markers

Abstract

Triticale (×Triticosecale Wittmack) is becoming increasingly important in agriculture and understanding its genetic diversity is essential for its continued improvement. Simple sequence repeat (SSR) markers are highly polymorphic and widely used for genetic diversity studies. Previous genetic diversity studies using SSRs have focused on the European winter triticale gene pool. Our objective was to investigate the genetic diversity and relationships of 80 hexaploid triticale accessions representing a more global gene pool using 43 wheat (Triticum spp.) and 14 rye (Secale cereale L.) SSR markers. Two hundred forty‐one alleles from 57 markers were detected with an average of 4.2 alleles per locus (ranged from 2 to 11 alleles per locus). The average gene diversity was 0.54 with a range of 0.07 to 0.86. Cluster analysis grouped the 80 accessions into five clusters that were generally consistent with the available pedigree information, country of origin, growth habit, and release year. Every larger cluster, however, included lines with unrelated pedigrees, different countries of origin, growth habit, and release year, which most likely is due to germplasm exchange among breeding programs. Genetic diversity estimates of the accessions evaluated with markers from different sources were similar (0.55 and 0.53 for wheat and rye, respectively), indicating that the wheat and rye markers detected similar genetic variability in the wheat and rye genomes of triticale.

Genetic diversity of Brazilian triticales evaluated with genomic wheat microsatellites

“…Tams et al (2004) determined polymorphism information content (PIC) of 0.54, indicative of moderate variability, in the evaluation of 128 triticale cultivars from five continents using three to five microsatellites per chromosome. The same value was also found by Kuleung et al (2006), when 80 hexaploid triticales were analysed, employing 43 wheat and 14 rye microsatellites.…”

“…However, it must be taken into account that these accessions come from only two breeding sources, Embrapa Trigo (43%) in Brazil and Cimmyt (57%) in Mexico ( Table 1). The PIC values (0.54) revealed for triticale by Kuleung et al (2006) and Tams et al (2004) were obtained for 80 and 128 genotypes, respectively, representing a broad spectrum of historic and modern triticale germplasm from 17 countries, five continents and at least 27 breeding programs. At the same time, the PIC of 0.71 determined by Prasad et al (2000) for wheat was calculated for 55 accessions from 29 countries, the PIC of 0.68 determined by Hai et al (2007) for wheat included accessions from four distinct continents and the PIC of 0.51 registered by Landjeva et al (2006) represented the wheat germplasm created in Bulgary over a period of almost 80 years.…”

“…Molecular markers such as microsatellites or SSRs (Simple Sequence Repeats) constitute an important tool for studies on genetic diversity, population structure, genetic mapping and crop breeding due to their abundance, codominance, level of polymorphism, reliability and easiness to assay (Röder et al, 1995(Röder et al, , 1998 Microsatellites of wheat or rye have been efficiently employed in analysis of the genome of triticale (Kuleung et al, 2004(Kuleung et al, , 2006Tams et al, 2004) and the estimates revealed on the genetic diversity of triticales from distinct continents indicate that the genetic base of this cereal must be extended (Darvey, 1986, Nascimento Junior et al, 2004. Analyzing the genome of five triticales from Russia, Mexico and the United States, using 176 microsatellites from wheat (148) and rye (28), Kuleung et al (2004) identified polymorphism in 31% of the used markers.…”

Genetic variability for coloured caryopses in common wheat varieties determined by microsatellite markers

“…Null alleles (0 in Table 2) were detected at 13 SSR markers. Kuelung et al (2006) also mentioned presence of null alleles.…”

“…These 25 genotypes were subjected to an analysis of genetic variability using 44 SSR markers located on chromosomes close to genes determining different pigmentation characteristics of the caryopsis. These were obtained from the database GrainGenes (2010) and from the literature dealing with wheat and triticale variation (Röder et al 1998;Sourdille et al 2001;Somers et al 2004, Dobrovolskaya et al 2006Kuelung et al 2006). Genomic DNA, isolated by means of a DNeasy Plant Mini Kit (Qiagen, Hilden, Germany) from mixed samples of 3-5 cultivated plants from the one leaf stage (i.e.…”