Occurrence and distribution of barley yellow dwarf virus (BYDV) isolates in central Ethiopia

A survey for BYDV was carried out in Ethiopia during the main rainy season of 1995 and the short rainy season of 1996 in the major barley-growing areas of the Arsi, North Shewa (Oromiya and Amhara regions) and West Shewa zones. Barley fields were sampled at 5-km intervals, and samples from each field were randomly collected.Samples were tested by the tissue blot immunoassay (TBIA) for the presence of the five BYDV serotypes. Of the 35 fields sampled in Arsi, 20 in NorthShewa (Amhara region), 24 in North Shewa (Oromiya region) and 33 in West Shewa, BYDV was detected in 23, 12, 5 and 14 fields, respectively. All five known BYDV serotypes were identified from samples collected in Arsi and West Shewa zones, whereas fourisolates
(PAV, MAV, RPV and SGV) were detected in North Shewa zone (Amhara region) and two isolates (MAV and RPV) from samples collected from North Shewa zone (Oromiya region). Mixed infections of two or more BYDV serotypes were found in all the survey zones. The BYDV serotypes most frequently detected in Arsi, North Shewa (Amhara region), North Shewa (Oromiya region) and West Shewa were PAV, MAV, RPV, and MAV, respectively. During the short rainy season of 1996, the five BYDV isolates were also detected in samples collected from the two North Shewa zones, where the SGV type was the most common in Oromiya region and PAV in Amhara region.