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

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.25

SEARCHING FOR AGRONOMICALLY VALUABLE ALLELES WITH ADVANCED BACKCROSS QTL ANALYSIS IN TWO H. VULGARE X H. SPONTANEUM CROSSES

TALAME’ V.*, BOSSOLINI E.*, MUHELBAUER G.**, BEN SALEM M.***, SANGUINETI M.C.*

*) Department of Agroenvironmental Science and Technology, University of Bologna, Italy

**) Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, USA

***) Institut National de la Recherche Agronomique de Tunisie, Tunis, Tunisia

barley, ABQA, QTL, biodiversity, drought stress

The objective of advanced backcross QTL analysis (ABQA) is 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). In ABQA, the QTL analysis is usually delayed until the BC2 generation, after selecting against characteristics which may have a negative effect from an agronomic standpoint (e.g., ear shattering in cereals). The BC lines carrying the favorable QTL alleles will already be rather similar genetically to the elite variety (ca. 87.5% in BC2) and thus amenable for commercial exploitation. ABQA has already proven its validity for the exploitation of exotic germplasm in tomato (Bernacchi et al. 1998; T.A.G. 97: 381-397) and rice (Xiao et al. 1998; Genetics 150: 899-909). We have undertaken parallel efforts in two barley populations in the attempt to uncover beneficial QTL alleles for drought tolerance from Hordeum spontaneum , the wild progenitor of barley. Wild barley is a valuable source of genes to improve biotic and abiotic stress tolerance. Results of three field trials conducted in 2001 under rainfed conditions in North-African countries with the first population showed that at a number of QTLs for grain yield the alleles increasing the value of the trait were contributed by H. spontaneum (Talamè et al. 2001; SIGA abstracts, 14.6). The results of field trials conducted with the same population in 2002 in Tunisia and Italy are being analysed. In 2002, a second population has been evaluated in a rainfed trial (3 reps) conducted near Bologna. This population includes 90 BC2F6 families; so far, these families have been genotyped with 118 SSRs and 45 AFLPs. Data have been collected for a number of morpho-physiological traits, yield and yield components. Statistical analysis of the data is in progress. QTL analysis will be performed to identify molecular markers associated with QTLs for the main morpho-physiological traits and for grain yield and its components.