Feldbeobachtungen zum Mehltaubefall von Erdbeersämlingen

Favourable natural conditions for mildew infection (Sphaerotheca macularis [Wallr. ex Fries] Jaczewski) of seedling progenies of strawberries (Fragaria ananassa Duch.) led to clear cut differences be~ween as well single plants as whole progenies. These differences could be classified into four groups :

1. Heavy infection,

2. moderate infection,

3. slight infection,

4. no visible infection (field resistance).

In general the field resistant plants, regardless of the crosses, possessed dark green glossy (leather) foliage originally derived from Fragaria chiloensis. Susceptible plants preferably showed leaf characteristics, originally introduced by Fr. virginiana, i.e. light green, tender foliage. These findings agree with those of Wilhelm (1955). Also the results of Peries (1962) can be interpreted under these aspects. Therefore selection of strawberries resistant to mildew will prefer the dark green glossy leaved phenotypes.