Sl Family Recurrent Selection in Autogamous Crops Based on Dominant Genetic Male-Sterility
- S. J. Knapp * and
- T. S. Cox
Recessive genetic male-sterility has been widely used to facilitate crossing in recurrent selection programs in autogamous crop species. Dominant genetic male-sterility, on the other hand, has not been widely used. Mass and half-sib family selection schemes have been described for the dominant male-sterile program. Our objective was to describe S1 family recurrent selection schemes and expected selection responses for the dominant male-sterile program. There is no mechanism for intermating selected S1 families in a dominant male-sterile program, other than manual emasculation and pollination, because S1 families are completely fertile. We proposed various S1 family recurrent selection schemes where intermating is done between selected S1 families and a male-sterile allele source as a means for overcoming this problem. These schemes include S1 family recurrent selection using the reference population as the male-sterile allele source and combined S1 and half-sib or S1 and full-sib family recurrent selection using half-sib or full-sib families, respectively, as the male-sterile allele source. Expected selection responses were described for selection of the same or different traits in different family types for combined family type selection schemes. The strengths of S1 family selection in a dominant genetic male-sterile program are that complete S1 family fertility eliminates the problem of male-sterile phenotype pleiotropy and selection response per year is often greater for S1 compared to mass or half-sib family recurrent selection. The weakness of S1 family selection in a dominant compared to a recessive male-sterile program is that expected selection response is less than that for S1 family selection in allogamous species where intermating is done strictly between S1 selected families.
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