(Singh and McIntosh, 1986a) (Plate 3-7)


SrBB (Luig, 1983).

Low Infection Type

X= to X.

Environmental Variability

Moderate, with lower infection types at cooler temperatures (Luig, 1983).


Common wheat. Sr8b appears to be derived from Barleta which was probably introduced to Argentina from Spain (Luig, 1983).

Pathogenic Variability

Australian populations are differentiated by their pathogenicity on wheats with Sr8b. Virulence was common in North America and South America, Europe and Africa in the early 1970s (Luig, 1983). In the survey of Huerta-Espino (1992) high levels of virulence were found in western Asia and eastern Europe, northern Africa and western Europe and South America. Populations in southern Africa showed a wide range of variability and those in China were generally avirulent.

Reference Stocks

v: Barleta Benvenuto C.I. 14196 (Singh and McIntosh, 1986a).

Source Stocks

Klein Titan (Singh and McIntosh, 1986a). Bezostaya Sr5 (RA McIntosh and AK Khanzada, unpublished 1989). Klein Cometa Sr30 (Singh and McIntosh, 1986a).


Seedling leaves of (L to R): Klein Cometa, Barleta Benvenuto, Klein Titan, Bezostaya and Chinese Spring; infected with A. pt. 34-(1), 2, 3, 7 [pSP8bP30] and B. pt. 126-5, 6, 7, 11 [p5p8bP30]. Sr8b and Sr30 in Klein Cometa interact to produce a lower infection type than conferred by Sr8b alone. The expression of Sr30 in Klein Cometa is shown when infection occurs with the 5r8b-virulent pathotype (B.).


Use in Agriculture

Sr8b is a rare gene. Bezostaya is the only non-South American wheat reported to carry this gene. However, the pedigree of Bezostaya includes Klein 33, which was of Argentinian origin. Resistance is effective to avirulent pathotypes in field plots (Singh and McIntosh, 1986a).