Reaction Of The Durum Recombinant Inbread Lines (Ril) Sw Alger/Gidara To Septoria Leaf Blotch (Septoria tritici)

S. Asaad ⁽¹⁾, A. El-Ahmed ⁽²⁾ and M. Nachit ⁽¹⁾.
⁽¹⁾ ICARDA, P.O. Box 5466, Aleppo, Syria.
E-mail: S.Asaad@cgiar.org
⁽²⁾ Faculty of Agriculture, Aleppo University, Aleppo, Syria. .

Abstract

Septoria tritici leaf blotch is considered a major disease problem of wheat worldwide, particularly in West Asia and North Africa countries. The objective of this study was to identify resistant lines in the Recombinant Inbred Line (RIL) cross SW Alger/ Gidara. During the 2000/01 season, 83 lines from the SW Alger/Grd cross were screened against Septoria tritici under controlled conditions. Ten-seeds/ entry was sown in two pots of 20- cm diameter (5 seeds/pot) containing a mixture of soil, sand and peat. Pots were placed in plastic house at 25±2 C0 and watered regularly. At the 5-7-leave stage plants were artificially inoculated with a mixture of 5 different aggressive isolates of Septoria tritici, collected and isolated from infected durum wheat grown in Syria. Pots were then covered with polyethylene tent for 48 h. Inoculation was repeated twice with 7 days interval. The number of infected leaves/plant as well as density of pycnidia formation (PF) on the lesion, after three weeks of inoculation was used to evaluate the severity of infection. This was recorded by using a 0-3 rating scale, where 0= no PF, 1= scarce PF, 2= moderate PF, and 3 heavy PF. The plant reaction was accordingly considered as 0=HR, 0.1-0.5= R, 0.6-1.0=MR, 1.1-1.5= MS, 1.6-2.0=S and 2.1-3.0= HS. Results revealed 10, 6 and 33 lines reacted as HR, R and MR, whereas 16, 14 and 4 lines reacted as MS, S and HS, respectively. Similarly, the number of infected leaves/plant was found 0, 0.5, 1.5, 2.2, 2.7, and 4.3, respectively. These results indicate the usefulness of SW Alger/Grd cross as a source of resistant gene (s) to S. tritici.