Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.37

PRODUCTION AND UTILIZATION OF SEXUAL “DOUBLE HYBRID” BETWEEN THE SOMATIC HYBRIDS S. MELONGENA (+)S. INTEGRIFOLIUM AND S. MELONGENA (+)S. AETHIOPICUM GR. GILO

Rotino G.l.*, Rizza F.**, Mennella G.***, Tacconi M.G.*, Alberti P.*, Vitelli G.***, Acciarri n.***

Istituto Sperimentale per l’Orticoltura – Sezione di Montanaso Lombardo (LO)*, Sede Centrale di Pontecagnano (SA)***, Sezione di Monsampolo del Tronto (AP)***; Istituto Sperimentale per la Cerealicoltura Sezione di Fiorenzuola (PC)**

Solanum melongena, Solanum integrifolium, Solanum aethiopicum gr. gilo, somatic hybrids, androgenic plants

Somatic hybridisation may provide an effective means for accessing wild germplasm and extending the genetic variability of eggplant by overcoming sexual barriers between species. Somatic hybrids between eggplant and the allied species S. integrifolium and S. aethiopicum gr gilo have been obtained and characterized. Both the allied species belong to the botanical section Oliganthes of Solanaceae and are resistant to Fusarium oxysporum f. sp. melongenae and to some strains of bacterial wilt (Ralstonia solanacearum ), which are very destructive diseases of eggplant. With regard to other features, the two species are extremely divergent. S. integrifolium shows spine and anthocyanin in stem, apex, leaf veins and petals, produce red fruits with ribs, it shows a certain degree of tolerance to spider mites; whereas S. aethiopicum gr. gilo is spineless and without anthocyanin and it is particularly susceptible to spider mites, the fruits show red skin at ripeness. Moreover, fruits of S. aethiopicum are used as food in some countries and show a delayed browning of the flesh after cutting.

With the purpose to incorporate the useful traits of both S. integrifolium and S. aethiopicum gr gilo into the eggplant gene pool, together with strategies based on distinct and direct employment of the somatic hybrids at tetraploid or diploid (after anther culture) level, crosses were also successfully performed between the two different somatic hybrids, each used both as male and as female parent. The resulting tetraploid progenies were inoculated with an Italian isolate of Fusarium oxysporum f. sp. melongenae and the fully resistant plants were used as anther donor. Four culture media, different in the type and level of growth regulators, have been employed. Androgenic plants have been obtained through embryos formation or callus proliferation from microspores. Dihaploids have been obtained and, after acclimatization, they are currently analyzed for their response to Fusarium using an Italian and a Dutch isolate. The regenerated plants are under phenotypic, molecular, biological and biochemical characterization. The first results about Fusarium resistance showed a good accordance of the data gathered following inoculation with the two isolates of Fusarium.

Besides their utility as potential valuable breeding materials, the materials obtained may be usefully utilized in genetic and molecular works to study the sources of resistance to Fusarium derived from S. integrifolium and S. aethiopicum gr gilo . Moreover, the “double hybrids” and the derived androgenic plants could be exploited to study the interaction of the three genomes (melongena, integrifolium and aethiopicum ) coexisting in the genetic materials obtained.