Quantitative genetic analysis of acid detergent fibre content in barley grain

Acid detergent fibre (ADF) in cultivated barley (Hordeum vulgare vulgare L.) grain, a major indicator of digestibility, negatively affects feed quality, especially of non-ruminant livestock and poultry. Genetic studies of barley grain ADF content have been very limited. The objectives of this study were to map quantitative trait loci (QTLs) affecting ADF content to a molecular marker linkage map in barley, and to determine interactions among the QTLs identified. A population of 150 doubled haploid lines (DHLs) derived from a cross of ‘Steptoe’/‘Morex’ was used for mapping. A total of five QTLs were identified; three with relatively large effects mapping adjacent to one another on chromosome 2H and one each on chromosomes 4H and 1H (5). The five QTLs explained 64.5% of total variation. Steptoe contributed high ADF alleles at all QTLs identified. In order to confirm that the three adjacent QTLs on chromosome 2H are distinct genetic units, three DHLs representing each QTL were selected for backcrossing to Morex. Analysis of F2 ADF data from these three crosses showed that the three QTLs are distinct heritable genetic units. Additivity among the three major QTLs on chromosome 2H and the QTL on chromosome 1H (5) were observed. q 2003 Elsevier Ltd. All rights reserved.