A NEW CONCEPT REGARDING THE IMPROVEMENT OF PLUM TREE BREEDINGS WITH TOLERANCE TO PPV (PLUM POX)

I. Botu, M. Botu, S. Preda, Gh. Achim

KEY WORDS: improvement, tolerance, virus, genotype

ABSTRACT

Romania is interested in the development and modernization of plum tree culture in the next years. This aspect is related to the implementation of programs for genetic improvement of plum tree breeds and port-grafts. One of the most important improvement objectives is represented by the creation of genotypes of plum trees that are resistant to the most spread and dangerous viral disease, i.e. (Plum-pox). It is very difficult to solve this problem from the scientific and economic point of view. At present, the improvement programs are based on trans-genesis method (not currently accepted integrally in the E.U.), conventional and some modern methods (multagenesis, androgynous somatic cross-breeding etc)

As Romanian and foreign plum tree breeds proved to have an accentuated sensitivity at PPV, we propose a new improvement strategy, based on the concept that new genotypes, resistant to PPV on long term of 16-25 years can be obtained if we use, as genitors, plants having genetic systems that do not allow accentuated accumulation of viral protein to descendents.

The system of resistance to Plum pos is not based on resistance genes, but on genes that delay infection at leave and fruit levels (16-25 years).

Such genotypes resistant over time (Andrea, Minerva, H 38-6-88, H 12-22-89) were created at Valcea R.D.S.P., but most of them originate from the local biotypes from Northern part of Oltenia (Scoldusi, DNT₃, Simbata 3, etc).