II. 27. Genetic studies of resistance to barley yellow mosaic virus of German winter barley cultivars.
W. Friedt, Biologische Bundesanstalt fur Landund Forstwirtschaft, Institut fur Resistenzgenetik, D-8059 Grunbach, Germany F.R.
Barley yellow mosaic virus (BaYMV) is one of the major diseases of winter barley in the Federal Republic of Germany. BaYMV is a soil-borne virus, which is transmitted by fungi (e.g. Polymyxa graminis into the winter barley plants. Therefore, chemical measures against this viral disease are either inefficient or uneconomic, and the only reasonable way of preventing yield losses by BaYMV (up to 70% of more) is by growing resistant cultivars. Although six released varieties are presently on the market (Table 1), they are not among the leading ones, due to some unfavorable agronomic characters (e.g. small grain). For that reason, new resistant cultivars with improved grain size are urgently needed.
Table 1. Ranking of registered winter barley cultivars in West Germany in 1984 (ANONYMOUS 1984); Ba-YMV-resistant cvs. are printed in large, bold letters.
Two-rowed cultivars
Igri (i), Sonja (2), Viola (11), Marylin (12), SONATE (13),
Kaskade (16),
DIANA (17), Irla (19), Isabell (27), Malta (28), GLORIA (35)
Six-rowed cultivars
Mammut (3), Tapir (4), Gerbel (5), Corona (6), Hasso (7), FRANKA
(8),
Ermo (9), Dura (10), Adonia (14), BIRGIT (15), Katja (18), Sigra
(20),
Doris (21), V.Gold (22), OGRA (23), Largo (24), Majo (25), Catinka
(26),
Ginso (29), Elster (30), Optima (31), Dunja (32), Bollo (33), Augusta
(34)
Furthermore, previous genetic studies have indicated, that the resistant varieties of Table 1, as well as other German breeding materials, all carry only one recessive resistance gene Table 2.
The genes of different cultivars are obviously identical, since their crosses do not segregate in F2, where all plants are resistant (Fridedt 1984). This gene was most probably derived from a commonly used cross parent. Therefore, additional resistance genes must be introduced in order to broaden the genetic basis of BaYMV-resistance in German barley breeding materials. Although numerous stocks in various gene bank collections are known to be resistant to BaYMV (e.g. Takahashi 1983, Huth 1984), only a few of them have been studied genetically, up till now. Two dominant resistance-genes were identified in 'Mokusekko 3' (Yml) and 'Mihori hadaka' (Ym2) respectively, by Takahashi et al. (1973). Recently, Ukai (1984) reported, that a recessive resistance gene in mutant 'Ea52' of the susceptible variety 'Chikurin Ibaraki 1' is not allelic to the former genes; therefore, Ukai (1984) proposed the symbol ym3 for this new gene. It is interesting to note, that the gene of mutant 'Ea52' does not provide resistance to the BaYMV-strains) prevailing in Germany, whereas the original variety 'Chikurin Ibaraki 1' proved to be resistant in our tests (Friedt, unpubl.).
Crosses of German cultivars to 'Mokusekko 3' did not segregate in F2, where all plants showed BaYMV-resistance. This result might be explained by allelism of the recessive gene in German materials and the dominant gene of 'Mokusekko 3'. However, it could also be explained by the presence of an additional (recessive) gene in the latter variety, which then' should be allelic to the gene in our material. Takahashi et al. (1973) had already interpreted their data by the possible existence of an additional "weaker" resistance gene in 'Mokusekko 3'. In order to identify the chromosomal location of the resistance gene in cultivars like 'Birgit' or 'Franka', these were crossed to the genetic marker stocks 'Colsess-orange lemma', 'L.T.16' and 'Nigrinudum' obtained from the Institute of Agricultural and Biological Sciences of Okayama University (Table 3). As expected, the F1-generation was susceptible to BaYMV. Extensive studies of the F2-generation have been initiated, but results are not yet available.
References:
Anonymus. 1984. Saatgutvermehrungsflachen im Bundesgebiet 1984. Blatt fur Sortenwesen 17:205.
Friedt, W. 1984. Fruhselektion auf Resistenz gegen Barley Yellow Mosaic Virus durch mechanische Inokulation. Nachrichtenbl. Deut. Pflanzenschutzd. 36:179-182.
Huth, W. 1984, Die Gelbmosaikvirose der Gerste in der Bundesrepublik Deutschland - Beobachtungen seit 1978. Nachrichtenbl. Deut. Pflanzenschutzd. 36:49-55.
Takahashi, R. (Adv. Ed.). 1983. Catalogue of barley germplasm preserved in Okayama University. Inst. for Agric. and Biol. Sci., Okayama University, Kurashiki, Japan, 217 p.
Takahashi, R., J. Hayashi, I. Inouye, I. Moriya and C. Hirao. 1973. Studies on resistance to Yellow Mosaic Disease in barley. I. Tests for varietal reactions and genetic analysis of resistance to the disease. Ber. Ohara Inst. 16:1-17.
Ukai, Y. 1984. Genetic analysis of a mutant resistant to barley yellow mosaic virus. Barley Genet. Newsl. 14:31-33.
