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 - 4.05

Molecular markers linked to a powdey mildew resistance gene from Triticum turgidum var. dicoccoides

CENCI A., VALENTINI F., SIMEONE R.

Dip. Biologia e Chimica Agro-Forestale e Ambientale, Università degli Studi, Bari

powdery mildew, resistance, wheat, molecular markers, backcross inbred lines

Wild relative of wheat are useful sources of agronomically important genes. Triticum turgidum var. dicoccoides, accession MG29896, resulted particularly interesting for high seed protein content and resistance to powdery mildew. In order to study single genetic factors influencing these traits in a durum wheat (T. urgidum. var. durum) background, several backcross inbreed lines (BILs) were produced from the MG29896 and the durum wheat cv. Latino, highly susceptible to powdery mildew. Among these BILs, line 5BIL29 (BC₅F₅) showed very high field resistance.

Line 5BIL29 and cv. Latino were checked for resistance to natural populations on different italian environments: in spite of hugh infection level for cv. Latino, no disease symptoms were observed for line 5BIL29. 5BIL29 x Latino derived F₁, F₂ (400 plants) and F₃ (120 F2 progenies) were essayed in field conditions: segregation analysis showed resistance inherited as single and dominant locus. About 200 microsatellite markerss were essayed with MG29896 and cv. Latino: about 100 resulted polymorphic and were essayed with 5BIL29 but only Latino amplification pattern was observed for the backcross inbred line. In order to find molecular markers linked to the resistance locus, pools were produced using DNA from 10 homozygous resistant and from 10 homozygous susceptible F₂ plants and bulked segregant analysis was performed by using AFLP. Restriction enzymes PstI and MseI were used for DNA digestion and selective amplifications were performed with specific primers PstI+4 and MseI+3. Seventy primer combinations were essayed and more than 4.800 bands were amplified. About 900 polymorphisms were observed between Latino and MG29896 whose 14 between Latino and 5BIL29. One AFLP marker resulted linked to the resistance locus at 0.9 cM.