QTL analysis of main and epistatic effects for quality traits in pasta wheat

RONCALLO PF; CERVIGNI GDL; BEAUFORT V; CONTI V; AKKIRAJU P; GOMÉZ P; CARRERA A; MIRANDA R; WEHRHAHNE L; JENSEN C; BARIFFI JH; HELGUERA M; DUBCOVSKY J D; ECHENIQUE V

St. Petersburg, Rusia

Congreso; 8th International Congress of Wheat.; 2010

VIR, CIMMYT, ICARDA, BGRI

Durum wheat is specially used in pasta production for their grain quality attributes. Gluten strength, grain protein content and yellow color are important semolina quality traits. Carotenoid pigment content is the main determinat for semolina yellow color. The main objective of this work were to map quantitative trait loci (QTL) and to detect epistatic QTL effect for grain protein content (GPC), gluten strength by SDS test (SDS), yellow color (CIE b*) and carotenoid pigment content (CPC). A population of 93 recombinant inbred lines (RILs) was generated by single seed descent from the cross between experimental line UC1113 (intermediate pasta quality) with the cultivar Kofa (excellent pasta quality).The RILs, the two parental lines and eight Argentinean varieties were evaluated during two consecutive growing seasons (2006/07 and 2007/08) in three locations of Argentina. A randomized complete block design with three replications was used. A composite linkage map was constructed on RILs population with 269 genetic markers (Zhang et al. 2008). Heritability were obtained with GENES software. Main effect QTLs were identified by environment using CIM method with Windows QTL-Cartographer version 2.0. Epistatic (QQ) effects and QTL × environment (QE) interactions were identified using QTLNetwork version 2.0. ANOVA showed that environmental effect were strong on quality traits. However, highly heritability values were obtained for SDS, CIE b* and CPC over 94%, whereas GPC had slighty lower values (70-86%). Color QTLs were mostly located on chromosomes 4AL, 5AS, 5BL, 6AL, 7AS, 7AL, 7BS, 7BL. A new QTL for CPC and CIE b* was identified on the short arm of chromosome 7A that show significant main and epistatic effect (7AS x 6BL). No QE and QQE (QTL x QTL x environment)  interactions were detected for CIE b* and CPC. On the other hand, QTLs for SDS were identified mainly on 1BL, 6AL, 6BL and 7AS, where SDS was strongly associated with the Glu-B1 locus on 1BL chromosome. The main QTLs for GPC were located on 3BS, 5AS and 7BL chromosome. 7BL GPC QTL shows a overlapping position with 7BL CPC QTL. Digenic QTL x QTL and enviromental interaction (QE and QQE) effects were identified affecting GPC. QTLs identified in present study will be useful to understand the genetic basis of these parameters and to improve pasta making quality.