PRODUCTION, CHARACTERIZATION AND BREEDING EVALUATION OF SOMATIC HYBRIDS BETWEEN POTATO AND SOLANUM BREVIDENS (PHIL)

One hundred fifty five somatic hybrid clones were produced between S. brevidens and two S. tuberosum cultivars (White Lady, Szazszorszep) by PEG mediated protoplast fusion. The usefulness of early identificatio n of fusion products based on presumed vigorous growth of hybrid colon ies was. The efficiency of selection system was evaluated by ''squash blot'' hybridization with a S. brevidens species specific repetitive D NA probe of selected colonies. The hybrid origin of selected colonies or regenerated plants in some cases was proved by chromosome counting or RFLP analyses. One hundred thirteen hybrid clones were planted into greenhouse for resting their overall development under in vivo condit ions as well as for investigating their male and female fertility. In case of 20 clones detailed morphological analyses were performed also. Most of the hybrids with cv. White Lady had normal development in viv o and showed mostly intermediate morphological characters of parents. All flowering clones proved to be female fertile and some of them male fertile too. In this combination B1 backcross progenies were produced by the use of four different S. tuberosum genotypes. Till this point we investigated the resistance level of 28 hybrid clones against Erwin ia carotovora ssp. carotovora causing bacterial soft rot of potato. Ba sed on artificial infection of tubers eleven clones were found to be h ighly resistant against this bacterial disease. In case of combination II with cv. Szazszorszep, most of the hybrids showed abnormal develop ment under in vivo conditions. Nevertheless all the clones characteris ed by relatively normal development and morphology proved to be both m ale and female sterile. By the results of above experiments we could d etermine the breeding value of hybrid clones belonging to the two diff erent fusion combinations and create the possibility to incorporate va luable genes of S. brevidens into the commercial potato breeding progr amme of Hungary.