Recently Skou and Haahr (1987) published results of screening for resistance to barley leaf stripe (Anamorph: Dreschlera graminea) in 1029 varieties and lines from Nordic collections.

Field inoculation close to 100% and testing in the greenhouse resulted in 0-10% attack in 42% of the barleys and of these 7% had no attack at all. A subsequent test of selected, resistant barleys inoculated with a monospore culture of the pathogen further separated in the barleys into different levels of resistance.

By use of a series of about 100 redoubled monoploids produced by the Bulbosum-technique for genetic analysis the high leaf stripe resistance of the variety 'Zita' was found to be monogenic and semi-dominant.

The resistance of a group of highly resistant, recent European varieties, including 'Zita', was traced in a pedigree analysis. The resistance was traced back to 'Vada' and 'Minerva' and the analysis further showed that this leaf stripe resistance gene by mere chance was bred into the north-west European barleys together with the Laevigatum powdery mildew resistance gene Ml- (La) (Table 1).

By scanning the barley breeding literature, it was found that the Laevigatum powdery mildew resistance was bred into more than 150 barleys where it is very likely that the Vada-resistance occurs in many of these barleys dependent of how many breeding generations back the resistance was bred into the varieties (Skou, Haahr, and Jørgensen 1988).

Some other highly resistant varieties without any known genetic background found may or may not have the Vada-resistance. They include 'Tystofte Kors' which was mentioned as resistant as early as in 1910 (Mortensen et al. 1911) and for that reason seems to be the first barley in the world described as resistant, and its resistance may be worldwide (cf. Shands and Arny 1944; Loiselle 1985). Further, some barleys that originate from other continents and Russia belong to this group.

A few highly resistant barleys, e.g. 'Freja', apparently possess two additively acting genes.

Crossing a resistant with a susceptible variety has now and then led to a variety with an intermediary level of attack, and in other cases transgressive effects have led to varieties with either a higher level of resistance or susceptibility than in their parents.

The considerable differences in the level of resistance among the moderately resistant or susceptible varieties suggests significant levels of partial resistance.

A series of more than 50 susceptible, related varieties and lines with 15-80% attack come from Finland, Norway, and Sweden. They descend mainly from 'Asplund', 'Maskin', and 'Svalöf Vega'. The genes or t1susceptibility promoting factors" in these varieties obviously have an additive effect.

References:

Knudsen, J. C. N. 1986. Resistance to barley leaf stripe. Z Pflanzenzuchtg. 96:161-168.

Loisaelle, R. 1985. Canadian Barley Genetic Resources Inventory 1985. (Research Branch Agriculture, Canada). 473 p.

Mortensen, M. L., S. Rostrup, and F. K. Ravn. 1911. Oversigt over landbrugsplanternes sygdomme i 1910. Tidsskr. f. Planteavl 18:317-350.

Shands, H. L. and D. C. Arny. 1944. Stripe reaction of spring barley varieties. Phytopathology 34:572-585.

Skou, J. P. and V. Haahr. 1987. Screening for and inheritance of resistance to barley leaf stripe (Drechslera graminea). Risø Report No. 554 (ISBN 87-550-1378-3), 96 p.

Skou, J. P., V. Haahr, and J. H. Jørgensen. 1988. Bekampelse af frobarne sygdomme i varbyg. Tidsskr. f. Landokonomi (in press).