Rita Tueryapina, Hans Peter Jensen* and Isaak Rashal
Institute of Biology, Latvian University, Salaspils LV-2169,
Latvia and
*Risø National Laboratory, DK-4000 Roskilde, Denmark
Powdery mildew caused by Erysiphe graminis f.sp. hordei is one of the widespread barley diseases in the Baltic countries. There has however been no special programme for disease resistant barley breeding until now. Therefore the use of resistance genes in new varieties has been uncontrolled and the selection was indirect. For this reason the knowledge about powdery mildew resistance genes has been lacking until now.
Sixteen Latvian barley varieties released in different years as well as 74 advanced breeding lines from Latvian plant breeding stations, 12 Lithuanian varieties and 6 Estonian barley varieties were included in the analysis. The investigation was carried out by analysis of resistance spectrum to 22 powdery mildew isolates kindly provided by Risø National Laboratory in Denmark. The genotypes were tested by inoculating 8-9 days old seedlings under greenhouse conditions. The seedlings were scored for the infection type according to the 0-4 scale (Torp et al., 1978). The results were analysed in accordance with the gene-for-gene theory. The resistance genes of the analysed genotypes were identified by comparing their reaction spectra with those of differentials possessing known genes.
Totally the presence of the following 8 named genes were detected: Mla6, Mla7, Mla9, Mla12, Mla13, Mlg, Mlk, MlLa; the tentatively named gene Ml(Ru3) and unidentified resistance from line KM 1192, designated as u1u2 (Jensen et al., 1992).
The results from the analysed Latvian varieties are given in Table 1.
For a long time Latvian barley varieties had no specific mildew resistance
genes. Those appeared first in the 1980s. Variety 'Klinta' besides resistance
MlLa possesses one additional unidentified resistance with a reaction
spectrum different from those of the known genes. Among genes recognized
in the tested barley varieties only Mla13 could be classified as
effective against the Latvian barley powdery mildew population (Rashal,
Tueryapina, 1996). Genes Mlg, Mlk, Mla7 and Mla9 are ineffective.
Resistance u1u2 was used in some varieties released after 1990.
This resistance is of medium efficiency in Latvia now.
Table 1. Powdery mildew resistance genes in barley varieties of
Latvian origin
| Variety | Year of registration | Detected resistance genes |
|---|---|---|
| Vairogs | 1930 | none |
| Kombainieris | 1955 | none |
| Priekulu 1 | 1959 | none |
| Priekulu 60 | 1972* | none |
| Stendes | 1972* | none |
| Abava | 1980 | Mlg |
| Agra | 1984* | Mla9 |
| Imula | 1990 | Mla9, Mlk |
| Linga | 1990 | u1u2 |
| Ilga | 1994 | u1u2 |
| Balga | 1995 | u1u2 |
| Ruja | 1995* | Mlg |
| Gate | 1995* | Mla7, Mlg |
| Rasa | 1996 | Mla7, Mlg |
| Klinta | 1996 | MlLa, +? |
| Sencis | 1996* | Mla13, Ml(Ru3), MLg, MlLa |
*Year released
The resistance genes used in other Baltic States differ from those used
in Latvian breeding. Analysis of Estonian varieties (Table 2) showed that
only one out of the tested five varieties possessed the ineffective gene
Mlg. Among 12 Lithuanian varieties (Table 3) only five had the specific
resistance genes: Mla6, Mla12, Mla13, Mlg or MlLa.
Table 2. Powdery mildew resistances genes in barley varieties
of Estonian origin
| Variety | Detected resistance genes |
|---|---|
| Anni | Mlg |
| Elo | none |
| Esme | none |
| Leelo | none |
| Muna | none |
Table 3. Powdery mildew resistances genes in barley varieties of
Lithuanian origin
| Variety | Detected resistance genes |
|---|---|
| Auksiniai | none |
| Auksiniai II | none |
| Dainiai | none |
| Dotnevos 4-eiliai | none |
| Dziugiai | none |
| Gausiai | none |
| Gintariniai | none |
| Auksiniai 3 | Mla6, Mlg |
| Aidas | Mla12 |
| Alsa | Mla12, Mlg |
| Ula | Mla13, Ml(Ru3), MlLa |
| Vilnieciai | Mlg |
The analysis of the Latvian advanced breeding lines show them to have a
wider set of resistance genes. In addition to those mentioned above they
possess genes Mla1, Mla3, Mla14, Mlp or Mlat, and
also some unknown resistance genes (Table 4).
Table 4. Powdery mildew resistances genes in barley breeding lines
of Latvian origin
| Detected resistance | Number of lines |
|---|---|
| Mla1 | 1 |
| Mla1, Mlg, MlLa | 1 |
| Mla3, Ml(Tu2) | 1 |
| Mla6, Mla14 | 1 |
| Mla6, Mla14, Mlg | 1 |
| Mla6, Mlat or Mlp | 1 |
| Mla7 | 2 |
| Mla7, Mlg | 3 |
| Mla7, Mlg, Mlk | 2 |
| Mla7, Mlg, +? | 1 |
| Mla7, Mlg, +? | 1 |
| Mla7, Mlg, +? | 1 |
| Mla7, Mlk | 3 |
| Mla7, Mlk, MlLa | 2 |
| Mla7, Mlk, Ml(IM9) | 1 |
| Mla7, Ml(IM9) | 3 |
| Mla9 | 3 |
| Mla9, Mlg | 1 |
| Mla9, Mlg, Mlk | 2 |
| Mla9, Mlk | 3 |
| Mla12 | 7 |
| Mla12, Mlg | 6 |
| Mla12, Mlg, U | 1 |
| Mla12, +? | 1 |
| Mla13, Ml(Ru3) | 3 |
| Mla13, Mlg, Ml(Ru3) | 2 |
| Mla13, MlLa | 1 |
| Mla13, Mlg | 1 |
| Mlg | 4 |
| u1u2 | 4 |
| u1u2, Mlg, +? | 1 |
| none | 9 |
The most used resistance sources in the tested material were Weihenstephan
(Mlg), Lyallpur (Mla7), Arabic (Mla12), Kwan (Mlk), Monte
Cristo (Mla7) and Rupee (Mla13). Less frequently were found
such popular sources in European varieties as Spontaneum (Mla6), Laevigatum
(MlLa), Algerian (Mla1) and Ricardo Mla3).
References:
Jensen, H.P., Christensen, E., Jørgensen J.H. 1992. Powdery mildew resistance genes in 127 Northwest European spring barley varieties. Plant Breeding 108:210-228.
Rashal, I., Tueryapina R. 1996. Barley powdery mildew in Latvia: Genetic structure of the pathogen population. In: Integrated Control of Cereal Mildews and Rusts: Towards Coordination of Research Across Europe. Limpert, E., Finckh, M.R., Wolfe, M.S. (eds.). European Commission - Directorate General XII - Science, Research, Development, Brussels, Luxemburg, p. 15-19.
Torp, J., Jensen, H.P., Jørgensen, J.H. 1978. Powdery mildew resistance genes in 106 northwest European spring barley varieties. Kgl. Vet. Landbohojsk. Årsskr.:75-102.