Abstract
The “Crossing-within-Spike-Progeny (CSP) method” is a method to efficiently screen for mutants in allogamous (cross-fertilizing) plants. This paper presents a theoretical analysis of how to minimize the total number of plants in the screening generation (T) and the total cost (Tc) required to detect one or more mutants with a given probability when using the CSP method. Tc depends on the number of plants per line in the screening generation (n), the number of plants per hill plot in the M2 generation (h), the ratio of the cost needed in non-screening generations to that in the screening generation (W), and the mutation rate per cell (p1). T was lowest when n = 1 (T = 47.93 × p1−1), irrespectively of h. On the other hand, the value of n which gave minimum Tc (designated n*) was not constant, but varied with h. n* was 6 when h = 2, increased as h increased, and was 15 when h = 48, when W = 10. Unlike in the case of autogamous species, the presence of chimeras in the M1 inflorescences greatly increased both T and Tc. A method for estimating the mutation rate per cell is also presented.
