Abstract
Self-compatibility, shoot-regeneration ability and embryoid formation in the first backcross generation (B1F1) between cultivated tomatoes of Lycopersicon esculentum and a wild species L, per, var. glandulosum were studied for the programme of transferring the high shoot-regeneration ability of L. per. var. glandulosum into L. esculentum. Self-compatibility in each B1F1 plant was assessed by fruit set and seed content that were determined by observing the B1F1 plants which flowered in the field and of which fruits were set under open pollination. From the results, three B1F1 plants were selected as completely self-compatible ones because they showed sufEicient fruit set and seed content. Shoot-regeneration ability was compared among eight BIFI plants together with a cultivated tomato, a wild species L. per. var. glalrdulosum and their F1 by means of in vitro culture of leaf segment. The results revealed that, with respect to shoot-regeneration ability, L. per. var. glalrdulosum was completely dominant against cultivated tomato and eight B1F1 plants segregated with a wide range of variation from plants nearer to L. per. var. glandulosum to those to cultivated tomato. Totally B1F1 plants were rather close to L. per. var. glandulosum. Two out of the three self-compatible plants were estimated to have a higher shoot-regeneration ability than cultivated tomato. In the experiment for embryoid formation, one self-incompatible B1F1 plant was used. Callus cells derived from leaf were cultured in suspension in 8E media supplmented with low concentrations of auxin and, subsequently, small masses of cells in size of 350∼850 um were cultured on MS agar medium supplemented with 1.0mg/l ZR. Embryoids began to appear in 15∼20 days. This confirms that som.e of the genes responsible for em-bryoid formation in L. per. var. glandulosum are transmitted to the first backcross genera-tion between L. esculentum and L. per. var. glavrdulosum. In addition to the conclusion, this experiment could also deepen the understanding about plant hormones, NAA and 2, 4-D, which added to the suspensio medium and ZR to the medium for embryoid formation.
