CHARACTERISTICS OF A SOMATIC HYBRID BETWEEN SOLANUM-MELONGENA L AND SOLANUM-SANITWONGSEI CRAIB

In order to transfer the growth habit and the resistance to Pseudomonas solanacearum from S. sanitwongsei to S. melongena, electrofusion was carried out. The fused protoplasts were cultured in KM(8p) medium supplemented with 1,000ppm wilt-inducing product secreted by a virulent strain of P. solanacearum. The regenerated plants were further screened on the soil contaminated with P. solanacearum. Only one plant survived. Several morphological traits of the surviving plant were intermediate between those of the parents, and the chromosome number was 48. The pollen viability averaged 82.3%, and fruits were set. The hybridity was confirmed using random amplified polymorphic DNA (RAPD) markers. The somatic hybrid exhibited a resistance to P. solanacearum comparable to that of S. sanitwongsei. The juvenile growth of the offsprings (S1 plants) obtained by selfing of the somatic hybrid was superior to that of S. sanitwongsei. The S1 plants were also as resistant to P. solanacearum as S. sanitwongsei. When the S1 plants were used as rootstocks for eggplants, the fruit yields were as high as those of eggplants grafted on S. sanitwongsei. It was considered that the S1 plants could be used as rootstocks for eggplant production.