Abstract
Forty heteroploid tomatoes arised out of five hundred seeds, which were obtained from the regenerated tetraploids produced by the decapitation-method. They could be already noticed in the seedling stage for the slowness of germination and the abnormality of cotyledons. The dwarfness and bushy form are two remarkable characteristics of the mature plants and their fruit-setting is very rare or none. The somatic chromosome numbers of the heteroploid plants so far examined are 49, 50, 51, 52, 53, and 54; namely 4n+1, 4n+2, 4n+3, 4n+4, 4n+5 and 4n+6 respectively. The heteroploidy may be caused by the gamates, which have super diploid chromosome numbers on the consequence of irregular division of pollen mother cells in the tetraploid tomatoes.
