Mapping the genomic regions encoding biomass-related traits in Cynara cardunculus L

Cynara cardunculus, a member of the Asteraceae family, comprises the three taxa var. scolymus (globe artichoke), var. altilis (cultivated cardoon) and the ancestral var. sylvestris (wild cardoon). The substantial quantities of lignocellulosic biomass produced by these plants (up to 30.0 t/ha year−1dry matter by the cultivated cardoon) can be used either as a source of bioenergy and/or as raw material for paper pulp production. Here, genotyping-by-sequencing to an F1population derived from a cross between a globe artichoke (C3) and a cultivated cardoon (ALT) genotypes has been used to perform a genome-wide linkage analysis, leading to the elaboration of a pair of highly dense genetic maps, each derived from one of the two highly heterozygous parental genotypes. In both maps, the number of linkage groups (17) matched the species’ haploid chromosome number. The F1population was phenotyped over two seasons with respect to plant height, stem number, capitulum number, leaf and stem fresh weight, and the dry weight of the whole plant, the leaves, the stems, the capitula and the achenes. The phenotypic data were combined with the linkage maps to identify 81 quantitative trait loci, of which 50 were placed on the C3 map and 31 on the ALT map. The loci were scattered over 13 linkage groups, and were clustered within 27 genomic regions, 22 of which harboured two or more QTL. Ten of these regions were specific to the C3 map and six to the ALT map, while the other 11 were represented on both maps. The 27 regions harboured in all 1960 genes, 83% of which could be functionally annotated. An enrichment for certain gene ontology terms was noted for the gene content of the genomic regions harbouring loci influencing seed yield and the number/weight of stems.