(Loegering and Sears, 1966) (Plate 3-19)


Srr12 (Rondon et al., 1966).

Chromosome Location

2B (Sears et al., 1957; Loegering and Sears, 1966); 2BL (Sears and Loegering, 1968). Sr16 is distal to, and genetically independent of, Sr9 (Loegering and Sears, 1966). It is allelic with a gene (SrKt2) in Kota (RA McIntosh, unpublished 1980).

Low Infection Type

2 to 3.

Environmental Variability

No variation was detected by Roelfs and McVey (1979).


Common wheat cv. Reliance. Sr16 is probably present in Kanred, a Crimean wheat used as one of the parents leading to Reliance and Thatcher.

Pathogenic Variability

Avirulence is uncommon. Huerta-Espino (1992) recorded avirulent cultures among collections from Ethiopia, Kenya, Nepal, Chile and Paraguay. Most isolates of the wheat stem rust are normally considered to be virulent. However, comparison of rust infections on seedlings of ISr16-Ra and Chinese Spring often indicate very slight reductions in uredinial development on the line with Sr16 (RA McIntosh, unpublished 1976).

Reference Stocks

i: ISr16-Ra (Loegering and Harmon, 1969); ITha 2B-Ra (Loegering and Sears, 1973).

s: Chinese Spring*7/Marquis 2B Sr9g (Williams and Kaveh, 1976); Chinese Spring*5/Thatcher 3B Sr12 (Loegering and Sears, 1973); Chinese Spring*4/Thatcher 2B Sr16 (Sears et al., 1957).

v: Reliance Sr5 (Rondon et al., 1966). Thatcher Sr5 Sr9g Sr12 (Loegering and Sears, 1966).

Source Stocks

Because of the high frequencies of virulence in the pathogen, searches for Sr16 are rarely undertaken. Consequently, Sr16 probably occurs in more wheat cultivars than has been reported. It is common in Thatcher derivatives (Luig, 1983), for example Manitou Sr5 Sr6 Sr7a Sr9g Sr12, Neepawa Sr5 Sr7a Sr9g Sr12, Lee Sr9g Sr11, Celebration Sr9g Sr12.


A. and B. Seedling leaves of (L to R): ISr16-Ra, CS/Thatcher 2B, CS/Marquis 2B, tine AE and Chinese Spring; infected with A. culture 80-E-2 [p9gP16PKt2] and B. pt. 126-5, 6, 7, 11 [p9gp16pKt2]. The first three lines with Sr16 are usually not as susceptible as Chinese Spring to Australian pathotypes. On the other hand, tine AE which possesses gene SrKt2 in a W2691 background, is fully susceptible to the second culture.
C. Four seedling leaves of ISr16-Ra; infected with USDA Cereal Rust Laboratory pathotype BDCN. Courtesy AP Roelfs.


Use in Agriculture

Not intentionally deployed in agriculture.