Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 2.30

IDENTIFICATION OF AGRONOMICALLY VALUABLE QTL-ALLELES IN WILD BARLEY (H. SPONTANEUM) THROUGH ADVANCED BACKCROSS QTL ANALYSIS

V. TALAMÉ*, M.C. SANGUINETI*, E. CHIAPPARINO*, H. BAHRI**, M. BEN SALEM***, R. ELLIS****, B.P. FORSTER****, S. RHOUMA***, W. ZOUMAROU***, R. TUBEROSA*

*) Department of Agroenviromental Sciences and Technology, University of Bologna, Via Fanin 44, 40137 Bologna, Italy

**) Ecole National D’Agricolture de Meknes, PBS40 Meknès, Morocco

***) Institut National de la Recherche Agronomique de Tunisie, 2049 rue Hedi Karray, Ariana, Tunis, Tunisia

****) Scottish Crop Research Institute, Invergowrie, DD2 5DA, UK

Hordeum vulgare, Hordeum spontaneum, ABQA, drought stress

Advanced backcross QTL analysis (ABQA) allows to quickly identify and exploit beneficial QTL alleles by integrating QTL discovery and variety improvement in a single process (Tanksley and Nelson 1996; T.A.G. 92: 191-203). The strategy relies on the evaluation of backcross (BC) families between an elite variety used as recurrent parent and a donor accession (often a wild species sexually compatible with the cultivated species). ABQA has already proven its validity for the exploitation of exotic germplasm in tomato (Bernacchi et al. 1998; T.A.G. 97: 381-397), rice (Xiao et al. 1998; Genetics 150: 899-909) and recently also in barley (Pillen et al., 2003; TAG. Published online: 2 April 2003).

In this study, ABQA was used on double haploid (DH) lines derived from an H. vulgare x H. spontaneum backcross to identify allelic variation in wild barley valuable for improving grain yield and other agronomically important traits in cultivated barley grown under conditions of water deficit in Mediterranean countries. DH lines were obtained by means of anther culture from BC₁F₂ plants derived from the cross between Barke (a European two-row cultivar) and HOR11508 (a wild barley accession). The DH lines characterized by negative agronomic traits such as ear shattering, excessive earliness and lateness, low kernel weight and/or dormancy were not considered. In total, 123 double haploid (DH) lines were genotyped with 58 AFLP and 59 SSR markers. The DH lines and the two parental lines were tested under conditions of varying water availability in three locations (Italy, Morocco and Tunisia) in replicated field trials. Data were collected for seven agronomic traits: growth habitus, heading date, plant height, ear length, ear extrusion, grain yield and 1000-grain weight. QTLs were detected by means of ANOVA based on simple regression for each marker. Genome regions were identified as containing a putative QTL when a significant effect was observed at one or more locations with P < 0.001 or at two or more locations with P < 0.05. Significant QTL effects were identified for all traits. Among the 81 putative QTLs identified, 43 (53%) agronomically favorable effects were contributed by the wild parental line. Interestingly. Although the majority (65%) of QTL alleles increasing grain yield was contributed by H. vulgare, at six chromosome regions (localized on chromosomes 2H, 3H, 5H and 7H) the alleles increasing grain yield were contributed by H. spontaneum. Our results revealed the effectiveness of the ABQA approach for identifying, in all three locations, QTL regions of H. spontaneum contributing agronomically valuable alleles, thus indicating that ABQA may represent a useful germplasm enhancement strategy for the release of cultivars better adapted to conditions of limited water availability.