Production of Somatic Hybrids Using Auxotrophic Nurse Cultures

A serious problem in somatic hybridization of plants is the selection of the hybrids because not only the somatic hybrids, but also the unfused protoplasts, will regenerate. Most of the somatic hybrids reported have been selected by complementation selection procedures using auxotrophic, resistant or chlorophyll-deficient mutants or non-regenerating wild type lines (1). Apart from difficulties in producing such mutants, mutagenic treatment may have a negative influence on interesting plant breeding material. Another possibility for somatic hybrid selection is to isolate heterokaryons mechanically and cultivate them individually in microdroplets (2) or in a protoplast suspension derived from a chlorophyll-deficient cell line (3).