Electrofusion for the production of somatic hybrid plants of Solanum melongena L. and Solanum khasianum C.B. Clark

Electrofusion has successfully been used for the production of somatic hybrid plants of Solanum melongena (eggplant) and S. khasianum. This fusion was carried out in a movable multi-electrode (2 mm apart) fusion chamber (500–700 μl capacity) containing a mixture (1:1) of mesophyll protoplasts of both species. Following an alignment of protoplasts induced by an A.C. fields of 125 V/cm and 1 Mhz, fusion was initiated by an exposure of the protoplast samples to a train of 3–4 D.C. pulses of 1.2 kV/cm, each 20 μs. The fusion rate was estimated at 30–40%, at least 30% of which were binary fusions. The mixture of fused protoplasts cultured in KM8p medium containing 0.2 mg/l 2,4-D, 0.5 mg/l zeatin, 1 mg/l NAA and 6.5% (w/v) glucose produced abundant calli, some of which gave rise to shoots on regeneration medium. Although no selection methods have been used, a total of 83 somatic hybrid plants were recovered from 83 individual calli in 3 fusion experiments. They accounted for 40–50% of all the regenerated plants. Several traits of the hybrids were intermediate to those of the parents. All the hybrid plants flowered preciously. The pollen viability averaged 12%, but none of them had set fruits. A random sample of the hybrids gave chromosome numbers ranging from 46 to 48. These numbers approximated to the expected tetraploid level ( 2n = 4x = 48 chromosomes ) The hybridity was confirmed by the banding patterns ofperoxidase activities whcih were composed of the bands of both parents.