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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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