Screening of barley germplasm for leaf blight (Bipolaris sorokiniana) resistance

Spot blotch or leaf spot, caused by Bipolaris sorokiniana (earlier Helminthosporium sativum) is the most common form of leaf blights of barley which appears in warmer and humid weather. The genetic studies for leaf blight in barley have concluded complex inheritance of leaf blight resistance at adult plant stage. Current Indian barley varieties are mostly susceptible to leaf blight under high input conditions and attempts have been made to introduce resistance for this fungal disease in Indian barley. In the present study, a set of 85 barley germplasm accessions under epiphytotic conditions were screened for leaf blight disease occurrence. Of these lines, 68 genotypes were found resistant, 7 were moderately resistant, 7 were moderately susceptible and 3 were found susceptible. The genotypes grouped as resistant were able to keep the disease level on the plant at very low level may be useful in developing mapping populations for QTL studies. The molecular markers reported for QTL regions of leaf blight resistance were used to screen these lines to validate their applicability in molecular studies for leaf blight in Indian conditions. Three molecular markers (Ebmac 705, Bmag 606 and Bmag 225) located on 3H genomic region of barley were found associated with leaf blight resistance during molecular screening. This suggests that the genomic region at 3H chromosome is significantly involved in inheritance of leaf blight resistance in Indian barley. This study may prove useful in selection of plant material and marker assisted selection for incorporating leaf blight resistance in Indian barley.