Development of inter-specific hybrids between Solanum melongena L. and Solanum sisymbriifolium Lam. through embryo rescue

Abstract

In present investigation, inter-specific hybridization between two species was carried out using a three-way cross with the aim to study the response of heterotic hybrids for cross-compatibility and to improve the fertility traits of interspecific cross such as pollen viability and density for further introgression of agronomically important traits. The present investigation highlights genotypic variation of for cross-compatibility between S. melongena hybrids and Solanum sisymbriifolium. Among three hybrids, H3 x Solanum sisymbriifolium (4%) and H4 x Solanum sisymbriifolium (1.5%) showed compatibility for fruit set and developed immature seeds only. The embryo rescue from 25 day-old fruits and in vitro culture on ½ MS medium supplemented with 2mg/L–1BAP showed germination. H5 x S. sisymbriifolium showed 49.4% embryo germination and produced four complete plantlets. Furthermore, all plants were morphologically variable for the presence or absence of spines, flower clustering, slightly curved/straight stigma tip, and flower color. The regenerated plantlets were intermediate to cultivated and wild parents for the quantitative traits. Two SSR markers viz., emg01A17, emh11001 and emb01E03 also confirmed the hybridity of three-way cross plants. Among four interspecific plants, one established high pollen viability (78.5%), while others were partial-fertile (62.8%) and all carried low pollen density (69-299 pollen/ 1cm2) at anthesis. Inbreeding and backcrossing of these plants to both cultivated and wild parents remained unsuccessful. This is the first report of developing a partially-fertile three-way cross between S. melongena and S. sisymbrifollium via embryo rescue.