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Wheat Information
Service
Number 74: 4-5 (1992)
Selective
resistance of short arm of chromosome 4E of Agropyron elongatum
to Erysiphe graminis f. sp. tritici isolates
S. S. Bains*, H. S. Dhaliwal and Sanjiv Gupta
Biotechnology Centre, Department of Plant Breeding, Punjab
Agricultural University, Ludhiana-141 004, Punjab, India
To-date, several alien addition lines of wheat have been developed in
different parts of the world (Evans and Jenkins 1960, Islam et al
1978, Dvorak 1980, Morris et al 1990). Some of them have been
successfully used as donors of disease resistance to wheat cultivars
(Sears 1956, Riley et al 1968, Cauderon et al 1973).
Wheat-rye and wheat-barley addition lines tested against Erysiphe
graminis f. sp. tritici from Punjab, India proved
susceptible though barley and rye parents of these lines were
resistant (Dhaliwal et al 1987).
In this investigation, a set of eight wheat-Agropyron
elongatum disomic and ditelo addition lines obtained from Dr B.
S. Gill of Kansas State University, Kansas, USA, was studied during
1990 and 1991.
Different lines were evaluated against an isolate of E.
gramtinis f. sp. tritici of known virulence, using the
detached leaf technique (Dhaliwal et al 1987) in the laboratory where
temperature ranged from 18 to 22oC. Conidial germination
and appressoria formation in vivo were studied, using the
"Cello-tape" method. Additionally, the leaf surface was examined
directly under the microscope to confirm the above observations.
Conidia germinated and the resulting germ tubes formed appressoria on
different lines (Table
1). Subsequent
development of E. graminis f. sp. tritici as visible
powdery mildew colonies did not, however, occur on all lines. The
line having disomic addition 4E was free from visible colonies of
E. graminis f. sp. tritici. The ditelo addition 4EL,
however, developed powdery mildew colonies.
E. graminis f. sp. tritici is a variable pathogen
having several distinct pathological races (Prabhu and Prasada 1963,
Sharma et al 1990). The simultaneous handling of more than one race
was not possible at Gurdaspur because of limited laboratory
facilities. Alternatively, therefore, the lines were field evaluated
at Keylong in Himachal Pradesh. E. graminis f. sp.
tritici is believed to over summer in hilly areas of Hintachal
Pradesh (Mehta 1930). It was found that addition 4E of A. elongatum
was susceptible to race(s) prevalent in Himachal Pradesh as no
addition line was powdery mildew free. Thus, addition line exhibiting
resistance against E. graminis f. sp. tritici from
Punjab, proved susceptible to race(s) prevalent in Himachal
Pradesh.
The powdery mildew resistance of 4E was, thus, race specific and it
appears to be associated with short arm of the chromosome as the
ditelo, addition 4EL was susceptible to E. graminis f. sp.
tritici from Punjab.
P. A. U., Regional Research
Station, Gurdaspur, Punjab, India
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