S01 - Session O7 - Identification and validation of QTLs for tuber quality related traits in yam (Dioscorea alata L.)

Authors: Gemma Arnau *, Adou Emmanuel Ehounou, Erick Maledon, Elie Nudol, Hélène Vignes, Marie-Claire Gravillon, Assanvo Simon P Nguetta, Pierre Mournet, Amani Michel Kouakou, Hana Chair, Fabien Cormier

Two diploid full-sib segregating populations comprising 121 progeny (population A, 74F x 'Kabusa') and 193 progeny (population B, 74F x 14M) were used to map several quality traits. All progeny and genitors were genotyped-by-sequencing (GBS) and a consensus high-density genetic map was constructed containing 1579 SNP loci, with a total length of 2613.5 cM and average distance of 1.68 cM between markers. Both populations were assessed over two consecutive years for seven important morpho-agronomic quality-related traits (tuber size, shape regularity, flesh colour, flesh oxidation, oxidation ratio, tubercular roots and skin texture). The heritabilities of most traits were high. Quantitative traits loci (QTLs) were identified for all the traits studied, with 34 QTLs detected on 8 of the 20 yam chromosomes. The fraction of total phenotypic variance attributable to a single QTL ranged from 11.1% to 43.5%. We detected significant correlations between traits and QTL co-localizations that were consistent with these correlations. Nine QTLs were validated on a diversity panel, including three for tuber size, three for shape regularity, two for skin texture and one for tubercular roots. The validated QTLs should be useful for breeding programs using marker-assisted selection to improve yam tuber quality.