Abstract: Most of the corn in the United States is grown from hybrid seed. The production of hybrid seeds necessitates the emasculation of the desired female parent plant. If this emasculation is carried out by hand, then it becomes a major cost factor. One method to overcome these costs is to obtain inbred lines of corn which have stable cytoplasmic male sterility. Such cytoplasmic male sterility should remain stable when the genome of the inbred line is replaced by the genomes of other inbred lines by backcrossing.Three major groups of cytoplasmic male sterility (C, T and S) have been extensively studied. In the past the cms S-type has not been extensively utilized in the production of hybrid corn seed because cms S-cytoplasms do not show stable male sterility and also in some backgrounds have a high rate of genetic reversion to male fertility. We describe here the production of a novel stable cytoplasmic male sterile strain (LBN) which remains stably sterile in combination with a large number of inbred corn lines.

Abstract: A process for the production of high purity hybrid Brassica seed, comprising (a) selecting a heterozygous, maximally self-incompatible parent plant, (b) cloning said selected plant to produce a first cloned parental line, the plants of which are both maximally self-incompatible and maximally clonal-incompatible, (c) crossing plants of said parental line with plants of a second parental line, and (d) collecting high purity hybrid seed from said first cloned parental line. The second parental line may also have been obtained by cloning a second maximally self-incompatible plant to obtain a second cloned parental line, the plants of which are both maximally self-incompatible and maximally clonal-incompatible. The second parent plant may be homozygous or heterozygous. The high purity hybrid seed may be collected from said second maximally self-incompatible cloned parental line or alternatively from both first and second maximally self-incompatible cloned parental lines.

Abstract: A method is disclosed which selects for different types of mutants expressed in cereal seed. The method allows rapid qualitative or quantitative screening of the aleurone GA.sub.3 -induced expression of alpha-amylase activity in half-seeds (without embryo). Half-seeds of the M.sub.2 population of mutagenized cereal seeds are incubated under selection pressures that normally inhibit the expression of alpha-amylase activity. These selection agents include metabolic inhibitors which may function at the level of transcription, translation, or protein secretion.These selection agents include antimetabolites such as amino acid analogs (e.g., S-2-aminoethylcysteine, p-flourophenylalaine, canavanine, etc.), antibiotics (e.g. Actinomycin D, cycloheximide, erythromycin, kanamycin, streptomycin, or tunicamycin), biocides, herbicides, water or salt stress. Such selection pressures may be applied to the half-seed method in the presence of absence of GA.sub.3, ABA, and at various incubation temperatures.

Abstract: A process for commercially producing high purity hybrid cabbage seed. One (or both) of the parental lines is rendered sib-incompatible by cloning a maximally self-incompatible parent plant so that the resulting line (or lines), consisting of cloned plants, is sib-as well as self-incompatible. The two parental lines, one or both of which is clonally derived, may then be crossed by natural pollination without encountering inbreeding of the cloned parental line (or lines). Prior difficulties in maintaining the parental inbred breeding lines are eliminated.

Abstract: New hybrid seed varieties and plants therefrom are rapidly developed and commercially produced. New hybrid seeds can be readied for market in as little as three years, compared to the conventional eight to twelve years required for preexisting techniques of hybrid seed production. Plant breeders are no longer limited to homozygous parents in the production of new hybrids.