same phenotype. The F2 of 85 plants was uniformly of the same phenotype, with no normal segregants. Inasmuch as homozygous viable, dominant seedling markers are rare, an allele symbol is applied to this mutant. Robinson, R. W., and B. R. Phills Over-coming sterility in an intergeneric hybrid. Solanum lycopersicoides, the most distantly related species that has been crossed with the  tomato, has never been   used in tomato breeding. It is known to possess genes for disease resistance and cold tolerance, but the very high degree of sterility in the intergeneric hybrid has prevented transferring these useful genes to the tomato. Several thousand backcrosses of tomato pollen to the maternal F1 were made, but without success. The problem of premature abscission of the F1 flowers was overcome by applying 25 to 50 ppm parachlorophenoxy acetic acid in lanolin to the pedicel, but the few fruit to develop were parthenocarpic and with no evidence of an embryo that could be cultured. Fluorescence microscopy revealed better pollen tube development in the reciprocal cross, in which the tomato was the maternal and the F1, the pollen parent, but the very low amount of pollen produced by the F1 is an obstacle to massive numbers of pollinations with F1 pollen. The only viable seed we have yet obtained from the intergeneric hybrid was produced by vibrating flowers of the F plants grown in growth chambers. Two F seeds have been obtained, both of them at 15°C. The number of seeds is too few to draw definite conclusions, but the lack of any seeds being produced at 20°C, 25°C, or 30°C suggests that the lower temperature is more favorable for seed production. One F2 plant closely resembled its S. lycopersicoides parent while the other F2 plant was similar to L. esculentum. The segregant resembling L. esculentum was fully self-ferule. It had fasciated fruit with colorless skin, similar to the effects of the f and y genes, demonstrating that novel variation occurs in the progeny of this intergeneric cross. Although the F2 segregant resembling L. esculentum is fully self-fertile, there does appear to be partial incompatibility in the backcross progeny to L. esculentum. This incompatibility is easily overcome with repeated backcrosses. Sree Ramulu, K., and M. Devreux Culture media for in vitro plant regeneration from different tomato organs. In tomato (L. peruvianum, L. esculentum, hybrid of L. esculentum x L. peruvianum) the potential of tissue culture techniques can be utilized in the 1) accelerated propagation of desirable mutants, 2) production and distribution of virus-free plants, 3) preservation of male sterile lines, rare self-incompatible genotypes, the array of S- mutants and background lines, 4) production of haploids and homozygous diploids, 5) solving certain important incompatibility problems, 6) determining the origin of regenerated individuals and 7) analysis of genetic stability in cultures and in regenerated plants. Several different media were tested in studies seeking a suitable one for organogenesis. The parts cultured include internodal segments, anthers and leaves. Eight different media on which shoot differentiation occurred were selected (Table 1): Stem culture - media 1-3 were used for L. peruvianum and media 2, 4 and 5 for the hybrid. Anther culture - media 6-8 were used for L. peruvianum and medium 4 for the hybrid. To induce root formation, the regenerated shoots were transferred to simple minimal medium supplemented with indole-3-butyric acid (5 mg/1). In leaf culture experiments, both shoot and root differentiation occurred on medium 9 (see Ancora, this issue of TGC). The types and frequencies of plants regenerated from cultures of different age on various media are reported elsewhere (see this issue of TGC).

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