THEORETICAL STUDIES ON THE METHODOLOGICAL PROCEDURES OF RADIATION BREEDING

V. PROCEDURES FOR TAKING X₂-SEEDS IN RELATION TO TILLERS FOLLOWING SEED IRRADIATION IN AUTOGAMOUS PLANTS

抄録

To detect at least one desirable mutant with a minimum total number of X₂-plants or of combined X₁- and X₂-plants, two methods were established as suitable in relation to tillers of X₁-plants.
They are: a type of the “one-plant-two-grain method” (method D₂) and of the “one-plant-three-grain method” (method E₃) in which one grain is taken from each of two or three heads of an X₁-plant respectively.
These methods have been evaluated by considering the probability that one or more plants with the mutant allele in homozygous recessive form will appear in the total X₂-plants in relation to the number of heads per X₁-plant and to the independent degrees of mutation among the heads of the X₁-plant.
The “one-plant-one-grain method” (method C) proposed by Yoshida (1962) is the best when the number of heads per X₁-plant (t) is equal to or smaller than three and method C or D₂ is the best when t_??_4.
No single method is known to cover all of the advantages. However, methods D₂ and E₃ will be better than the “one-plant-two-grain method” and the “one-plant-three-grain method” proposed in the first report of this series when t_??_2 and t_??_3 respectively. Generally speaking, it does not seem advantageous to use the “one-ear-one-grain method”. especially the “one-ear-two-grain method” and the “one-ear-three-grain method”.