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Wheat Information
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Number 82: 8-10 (1996)
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linkage of the Agropyron elongatum gene Sr26 for stem rust
resistance to the centromere of wheat chromosome 6A
M.V. Prabhakara Rao
Nuclear Agriculture Division, Bhabha Atomic Research Centre,
Bombay 400 085, India
Summary
The Agropyron elongatum gene Sr26 for stem
rust resistance on chromosome 6A of bread wheat variety Kite was
mapped by using ditelo-6AL (beta arm). There was no pairing in
F1 between chromosome 6A of Kite carrying the
Agropyron segment and telo-6AL of Chinese Spring. Analysis of
test cross progeny for cytological constitution and rust resistance
failed to recover any crossover between Sr26 and the 6A
centromere.
Introduction
Knott (1961) transferred the gene Sr26 for stem rust
resistance from Agropyron elongatum chromosome 6Ag to
common wheat chromosome 6A by means of X-ray induced translocation.
This resistance gene has been incorporated into the Australian wheat
cultivars Eagle, Kite and Jabiru which are widely cultivated (Luig
1978). McIntosh (1978) lists Sr26 as being located on
chromosome arm 6A (beta). However, intra-chromosomal mapping of
Sr26 on 6A has not been reported and the present study was
undertaken to determine this.
Materials and methods
The Australian wheat variety Kite was crossed to Kalyansona
mono-6A and Chinese Spring ditelo-6AL. In the cross to mono-6A,
monosomic and disomic F1's were identified cytologically
and selfed. F2 progenies were scored for resistance to
stem rust. The monotelodisomic F1between ditelo-6AL and
Kite was studied cytologically and test crossed to Kalyansona
(susceptible variety). The test cross progeny was analyzed for both
cytological constitution and resistance to stem rust.
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