Articles
BREEDING OF PLUM CULTIVARS RESISTANT TO SHARKA (PLUM POX) DISEASE
The two cultivars assessed previously as being immune, Scoldus No. 1 and Zh’lta Butilcovidna, as well as partially resistant cultivars Opal and Cacanska Najbolja and tolerant cultivars Stanley, Cacanska Lepotica, Large Sugar Prune and Ruth Gerstetter were used as sources of genetic resistance.
A total of 12 crosses resulted in 367 seedlings which were multiplied on myrobalan and in their first year inoculated with a local sharka virus strain.
On the basis of the symptom developed, some 285 of them were rejected in their second year.
The hybrids that developed no sharka symptoms on leaves (82) were screened by means of ELISA technique and 8 of them were found to be infected.
The hybrids which were not infected (74) were regrafted on myrobalan and inoculated once more.
Over the period of several years, 56 of hybrids showed complete resistance.
The resistant hybrids were obtained from 9 parental crosses, most of them (20) deriving from a cross Large Sugar Prune × Zh’lta Butilcovidna.
On the basis of positive pomological characteristics shown until now, 7 hybrids were selected for further research: G/8, G/12, G/18, G/19, H/3, 3/15 and 2/83 (5/44).