QTL Analysis of principal and epistatic effects for quality traits in pasta wheat

RONCALLO P; CERVIGNI G,; BEAUFORT V; CONTI V,; AKKIRAJU P,; GÓMEZ P,; CARRERA A,; MIRANDA R,; WEHRHAHNE L,; JENSEN C,; BARIFFI J,; HELGUERA M,; DUBCOVSKY J ; VIVIANA ECHENIQUE

San Petersburgo

Conferencia; 8th International Wheat Conference; 2010

IWC

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 determinant of semolina yellow color. The main objectives of this work were to map quantitative trait loci (QTL) and to detect epistatic QTL effects for grain protein content (GPC), gluten strength (measured by the SDS test), 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 the line UC1113 (intermediate pasta quality) with the var. Kofa (excellent pasta quality).The RILs, the 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. QTL mapping was performed using the genetic map reported by Zhang et al. (2008, TAG 117 (8): 1361 - 1377). Heritability was calculated using the GENES software. Principal QTL effects were detected for each environment using the CIM method with Windows QTL-Cartographer version 2.0. Epistatic (QQ) effects and QTL × environment (QE) interactions were identified using QTLNetwork version 2.0. The effect of the environment was strong, affecting all the quality traits considered, as was shown by the ANOVA test. However, high heritability values (³ 94%) were obtained for SDS, CIE b* and CPC. GPC showed slighty lower values (70-86%). QTL affecting color 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 principal 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, QTL 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 QTL for GPC were located on 3BS, 5AS and 7BL chromosome. 7BL GPC QTL showed an overlapping position with 7BL CPC QTL. Digenic QTL x QTL and enviromental interaction (QE and QQE) effects were identified affecting GPC. The QTL identified in the present study will be useful to understand the genetic basis of the traits under study and to improve durum wheat cultivars with better quality characteristics for pasta making.