EVALUATION OF SCAB-RESISTANT APPLE PROGENIES FOR POWDERY MILDEW TOLERANCE

E. Pitera, J. Bogdanowicz
In the apple breeding programme for scab-resistance and tolerance to apple powdery mildew, we tried to find parents which transmit to the majority of their progeny a high level of mildew resistance.

During three years a total of 16 scab-resistant (Vf) apple progenies derived from 17 scab-susceptible and scab-resistant cultivars and selections were evaluated for susceptibility to Podosphaera leucotricha /Ell. et Ev./ Salm., under field conditions severe mildew infection occurred.

None of the 1,480 tested scab-resistant hybrids exhibited complete field immunity to apple powdery mildew. Only three crosses: 'Wealthy' x 'Primula', 'Idared' x U 211 ('Primula' open pollinated) and 'Gorjaczkowski Seedling' ('King of the Pippins' open pollinated) x 'Liberty' yielded progeny the majority of which very slightly or slightly susceptible to mildew ther crosses gave a relatively low proportion of seedlings in this class.

It is concluded that among apple progenies resistant to scab, derived from scab-susceptible and scab-resistant cultivars or selections (M. floribunda 821), distinct differences in the susceptibility to apple powdery mildew occur. The data obtained indicate that it is possible to select cultivars and clones for hybridization which would result in a high proportion of seedlings highly resistant to mildew among those resistant to scab. For conditions of Poland sources for mildew resistance could be, for example: 'Wealthy', 'Gorjaczkowski Seedling', 'Primula', U 211 and others.

Pitera, E. and Bogdanowicz, J. (1992). EVALUATION OF SCAB-RESISTANT APPLE PROGENIES FOR POWDERY MILDEW TOLERANCE. Acta Hortic. 317, 81-88
DOI: 10.17660/ActaHortic.1992.317.7
https://doi.org/10.17660/ActaHortic.1992.317.7
317_7
81-88

Acta Horticulturae