抄録
1) Plants or dormant seeds of three different forms of sesame (Sesamum indicum L.) cultivated in Japan, B1D(BAN-type), WD(3BO-type) and WD8 (QAN-type), were treated with four different radiations, (β-ray from P32, X-ray, γ-ray from Co60, and β-ray+X-ray).
2) Morphologically modified plants and several mutants obtained from the treated plants or from their progenies were compared with the controls as to vegetative and floral organs.
3) Three important morphological changes were observed: Alteration of phyllotaxis, development of nectary to flower or capsule, and alteration of loculus number per capsule by addition of an extra carpel.
4) The extra-floral nectary of Sesamum is homologous to the floral bud; by the radiation treatment, several transitional forms from nectray to flower are obtained.
5) The form B1D(BAN-type), gives many modified and mutant types and among them there are the same types as 3BO-type(WD) and QAN-type(WD8), used as the materials in the present study.
6) In certain mutants, there was a greater increase in the seed yield per plant than in that (yield) of the control; therefore, such mutants were marked as beneficial ones (Mutant SM3-20, SM3-22, etc.).
7) The relation between the normal cultivated type and the induced mutant type is discussed from the sesame evolutional point of view, the result proving that B1D(BAN-type) may be the most primitive type among the sesame forms cultivated in Japan.
