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

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Abstracts of posters

GENETIC MAPPING OF MOLECULAR MARKERS IN DURUM WHEAT USING TWO RIL POPULATIONS

PAGNOTTA M.A.*, NACHIT M.M.**, ELOUAFI I.**, TANZARELLA O.A.*, SORRELLS M.E.**, PORCEDDU E.*

* Dipartimento di Agrobiologia e Agrochimica, Università della Tuscia, Via S. Camillo de Lellis, 01100 Viterbo, Italy

pagnotta@unitus.it

** ICARDA, CIMMYT/ICARDA, Durum Improvement Program, P.O. Box 5466, Aleppo, Syria

*** Department of Plant Breeding, Cornell University, Ithaca, NY14853, USA

durum wheat, molecular markers, RFLP, genetic map

Durum wheat (Triticum turgidum L. spp durum) is a very important crop in the economies of the Mediterranean region, USA, and Canada. However, limited research has been carried out in the field of linkage maps and QTL (quantitative trait loci) analyses, as compared with other cereals. In collaboration with other Institutions, the University of Tuscia has participated to the construction of two genetic maps of durum wheat. The former was obtained using RILs (Recombinant Inbred Lines) from an interspecific cross (durum wheat cv Messapia x an accession of T. dicoccoides), whereas RILs deriving from an intraspecific cross between two durum cultivars (Jennah Khetifa and Cham 1) have been used for the most recent map. The two durum wheat parents were chosen since they were polymorphic for a high number of markers. “Jennah Khetifa” is a landrace collected in 1990 in the south east high plateau of the Atlas Mountains of Morocco, it shows specific adaptation to North African continental dryland. It is tall, moderately resistant to drought, cold, leaf rust (Puccinia recondita Rob.), powdery mildew (Erysiphe graminis DC.), common bunt (Tilletia caries D.C.), and to septoria leaf blotch (Mycosphaerella graminicola {Fuckel} Schroeder), but it is susceptible to yellow rust (Puccinia striiformis Westend.). “Cham 1” combines wide adaptation with high yield potential and yield stability. “Cham 1” is early, resistant to yellow rust and Russian wheat aphid, but is susceptible to leaf rust, septoria leaf blotch, and powdery mildew. Additionally, it shows high values for osmotic adjustment and quality. Several different markers (RFLPs, SSR, AFLPs, coding sequences and seed storage proteins) have been assigned to the durum wheat chromosomes and used in constructing the two maps. The former map [Blanco et al. 1998, TAG 97:721-728] covers 1352 cM with 213 loci, while the last [Nachit et al. 2001, TAG 102: 177-186] includes 306 markers covering a total of 3598 cM in all 14 chromosomes. The average map distance between markers ranges between 8.3 cM for chromosme 7A and 15 cM for 5B, with an overall average of 11.8 cM and some gaps exceeding 30 cM. There is a substantial agreement and co-linearity between this genetic map and other published Triticeae maps, in particular the consensus map by Van Deynze et al. (1995a; 1995b) [Genome 38:45–59; MGG 248:744–754]. However, some minor inconsistencies were detected. Among the different kind of markers used to construct both maps, several RFLP probes (UTV) were developed at the University of Tuscia, Viterbo. In the RIL population from the Messapia x T. dicoccoides interspecific cross, out of 77 probes screened by hybridisation to DNA of the parental genotypes, digested with 5 restriction enzymes, 56 detected polymorphisms with at least an enzyme, producing a total of 97 markers, 73 of them were mapped. In the second intraspecific cross between the durum wheat cultivars “Jennah Khetifa” and “Cham 1”, out of the 118 probes screened using parental DNA digested with 5 restriction enzymes, 56 of them detected polymorphisms between the parental lines for at least one enzyme and produced 82 markers 52 have been mapped. Ten probes could not be linked to any linkage-group. Out of the 66 UTV probes utilized in both mapping populations, 19 UTV probes were mapped in both RILs, 34 UTV probes only in the RILs from the interspecific cross and 13 UTV probes only in the lines from the intra specific cross. There is a substantial agreement between the two maps for the location UTV probes, even though minor differences have been detected. The results obtained show the potential usefulness of the mapped probes for future genetic analysis of durum wheat.