'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 BREEDING OF NEW FRUIT AND GRAPE VARIETIES WITH COMPLEX DISEASE RESISTANCE N. SAVELYEV All-Russian Research Institute for Genetics and Breeding of Fruit Plants, 393770 Michurinsk, Russia

On the base of the genetic investigations conducted in out institute, the following dominant genes were identified: A -Coccomyces hiemalis Higg resistance cherry,Septoria ribis Desm resistance - [R₁(Sr₁),R₂(Sr₂),R₃(Sr₃)] in currant, Plasmopara vitikola Berl et de Toni (Pv_(a)) and Oidium Tuckeri Berk. (Un_(v)) resistance in grape. Tuciness controlling gene (Su) and astringency controlling gene (Ta) in pear fruit and poor growth habit (o₂) gene in cherry were also identified. Application of Malus floribunda derivatives with Vf gene and polygenic resistance in hybridisation produced the new highly productive apple varieties - "Skala", "Uspenskoye", surviving at -40oC and are characterised by monogenic scub resistance, poor growth habit (tree height 3,3-3,7 m), high quality of fruit and their weight 160-300g and higher concentration of vitamin C (25-27 mr%) and P-active compounds (above 300mg%). Inclusion of Pyrus ussuriensis in crossings enabled us to obtain winter resistant varieties of pear "Pamyati Jakovleva", "Nezhnost", "Svetlyanka" and "Avgustovskaya rosa". They have high fruit quality and complex resistance against Venturia pirina Aderh, Entomosporium maculatum Lev., Septoria piricola Desm.