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Karyological Studies an a Spontaneous Haploid Mutant of Brassica Napella

1933; International Society of Cytology; Volume: 4; Issue: 4 Linguagem: Inglês

10.1508/cytologia.4.457

1348-7019

Toshitaro Morinaga, Eiichi Fukushima,

Plant tissue culture and regeneration

In the rape or "Seiyo-Undai"1) (B.Napella) field, there are found in places a certain type of highly sterile individuals .Such individ uals can be easily detected among the normal in the end of flower season owing to their continuous and successive blooming.In 1927 the authors collected some seeds from those sterile individuals, and the offspring-tests were made for two generations in which, contrary to expectation, no sterile plants appeared.Thus the problem has lost its interest and the authors' attention has not been paid for years to this sterile type.In the spring of 1933, however, an idea , oc curred to the authors, that such spontaneous, highly sterile individ uals might be haploids which produce diploid offspring.Closer in vestigations proved this supposition to be correct.This is the first known case of haploid plants in Brassica.NOGUCHI's report (2) treat ing maternal hybrid has often been misquoted in this connection.In the rape field otherr types of sterility were also met with.Among those especially a type with a higher number of chromosomes than the normal attracted the authors' attention.The haploid mutant: Plants of this type of sterility occur in the field far more than those of the other types.The leaves and flowers are obviously smaller than those of diploid in the same line.Though the plant is generally lower in hight than the diploid, it may surpass the latter in bight , on account of its continuous development of inflorescences.The epidermal cell of the haploid was, in a few individuals examined, markedly smaller than that of the diploid.Half