Functionally associated molecular genetic marker map construction in perennial ryegrass (Lolium perenne L.)

Abstract

A molecular marker-based map of perennial ryegrass (Lolium perenne L.) has been constructed through the use of polymorphisms associated with expressed sequence tags (ESTs). A pair-cross between genotypes from a North African ecotype and the cultivar Aurora was used to generate a two-way pseudo-testcross population. A selection of 157 cDNAs assigned to eight different functional categories associated with agronomically important biological processes was used to detect polymorphic EST-RFLP loci in the F(1)(NA(6) x AU(6)) population. A comprehensive set of EST-SSR markers was developed from the analysis of 14,767 unigenes, with 310 primer pairs showing efficient amplification and detecting 113 polymorphic loci. Two parental genetic maps were produced: the NA(6) genetic map contains 88 EST-RFLP and 71 EST-SSR loci with a total map length of 963 cM, while the AU(6) genetic map contains 67 EST-RFLP and 58 EST-SSR loci with a total map length of 757 cM. Bridging loci permitted the alignment of homologous chromosomes between the parental maps, and a sub-set of genomic DNA-derived SSRs was used to relate linkage groups to the perennial ryegrass reference map. Regions of segregation distortion were identified, in some instances in common with other perennial ryegrass maps. The EST-derived marker-based map provides the basis for in silico comparative genetic mapping, as well as the evaluation of co-location between QTLs and functionally associated genetic loci.

Four QTLs determine crown rust (Puccinia coronata f. sp. lolii) resistance in a perennial ryegrass (Lolium perenne) population

“…This figure is in the same order of magnitude as that previously reported in other Lolium studies Jones et al, 2002a, b;Thorogood et al, 2002;Faville et al, 2004;Inoue et al, 2004;Warnke et al, 2004). Apparent segregation distortion can be due to statistical error, genotyping and scoring errors or can be a real biological phenomenon.…”

“…In this procedure, the mapping family consists of an F 1 progeny derived from a pair-cross between two unrelated, highly heterozygous individuals. This mapping approach has been applied with success in several species (apple, Maliepaard et al, 1998;poplar, Wu et al, 2000), and also in Lolium (Faville et al, 2004;Warnke et al, 2004).…”

A high-density consensus map of barley to compare the distribution of QTLs for partial resistance to Puccinia hordei and of defence gene homologues

“…Several authors already mapped QTLs on linkage maps that contain GTMs (Chen et al 2001;Faville et al 2004;Pajerowska et al 2005). This may allow the identiWcation of associations between markers that are based on genes with known or putative function and QTLs for agronomic traits.…”

Assessment of Genetic Diversity among Sugarcane Cultivars (<i>Saccharum officinarum</i> L.) using Simple Sequence Repeats Markers

“…These results suggest that genotypes of sugarcane have a high similarity of allele, which could result in lower genetic gain for selection. In terms of the discovery of SSR, development of functional primer pairs and polymorphism detection EST-SSR markers are less efficient than DNA-derived SSRs, however these caveats are balanced by the relatively low expense with EST-SSR development as a product of a genomic database (Faville et al, 2004).…”