The degree of resistance to Colletotrichum trifolii was highly variable among red clover cultivars. Seven weeks after spray inoculation plant survival ranged from 3 % to 52 %. The new cultivars Pavo and Merula exhibited the highest level of resistance. The other Swiss cultivars of the persistent «Mattenklee» type showed an intermediate level of resistance. Cultivars of the short-lived type were generally the most susceptible among the cultivars tested, with the exception of cultivar Tedi, which exhibited a 31 % resistance. Of the cultivars of Medicago sativa L. evaluated, all five were very susceptible to a C. trifolii isolate, which had been found on diseased red clover plants in Switzerland. None of the red clover cultivars was severely affected by C. destructivum. Resistant and susceptible plants were selected and crossed reciprocally in a diallel design. Anthracnose resistance appeared to be highly heritable. Progeny of crosses between resistant plants exhibited a mean plant survival of 81 %. In the F1 populations from crosses between resistant and susceptible specimens, plants survived at a rate of 42 %. Crosses between susceptible plants produced F1 populations which were highly susceptible: only 8 % of the plants survived. The data suggest that in the populations tested, few partly dominant genes are involved in anthracnose resistance.
Spring J.-L-, Zufferey V., Verdenal T., Reynard J.-S., Lorenzini F., Bourdin G., Blouin A., Carlen C., Jermini M., Morisoli R., Ferretti M.
Five Merlot clones bred in Switzerland are currently being distributed by the certification sector. A multiyear trial conducted by Agroscope in Gudo (Canton of Ticino) has made it possible to compare them with French and Italian reference clones and to highlight their very good performances.
Arbuscular mycorrhizal fungi are important for healthy soils and crops. A pan-European study shows that plant-protection products adversely affect these fungi, reducing their ability to supply plants with phosphorus via their roots.
Birdsfoot trefoil and sainfoin are used in mixtures for perennial hay meadows and for tannin-containing fodder. Agroscope is adding two new cultivars of birdsfoot trefoil to the ‘List of Recommended Varieties of Forage Plants’, whilst there is no change in the case of sainfoin.