US 4,658,084 A · Hybridization using cytoplasmic male sterility and herbicide tolerance from nuclear genes

Abstract

The process of the present invention provides a convenient route for producing a predetermined hybrid variety of a crop which is capable of undergoing both self-pollination and cross-pollination. Cytoplasmic male sterile plants which also exhibit herbicide tolerance attributable solely to nuclear genes are the key plants for use in the present process. Economical bulk planting of the key plants with either maintainer or restorer plants is made possible. Following cross-pollination from a pollen source which lacks the herbicide tolerance unneeded plants effectively are eliminated by use of a herbicide. For instance, unwanted plants may be effectively eliminated immediately after pollination or prior to pollination in the succeeding generation (provided the requisite genes for herbicide tolerance are present therein) to make possible the existence in an unharmed state of a substantially homogeneous stand of the desired plants. In a preferred embodiment cytoplasmic male sterile plants, plants resulting from the self-pollination of a maintainer, and restorer plants are planted in a substantially random population prior to the application of two different herbicides (as defined) at the appropriate times. The process of the present invention is applicable to grain crops, forage crops, seed-propagated fruits, seed-propagated ornamentals, and industrial species. In a particularly preferred embodiment a predetermined variety of Brassica napus (i.e., rape or improved forms thereof known as canola) is formed which is the product of cross-pollination.

Claims70

Dependent claims

An improved process for producing a substantially homogeneous population of plants of a predetermined hybrid variety of a crop which is capable of undergoing both self-pollination and cross-pollination comprising:

(a) growing in a first planting area a substantially random population of (1) cytoplasmic male sterile plants which exhibit tolerance to at least one herbicide attributable solely to homozygous dominant nuclear genes, and (2) male fertile plants which are capable of pollinating said cytoplasmic male sterile plants and which lack said herbicide tolerance because the presence of homozygous recessive nuclear genes for such trait, whereby said cytoplasmic male sterile plants (1) and said male fertile plants (2) are pollinated with pollen derived from said male fertile plants and seed is formed on said cytoplasmic male sterile plants and on said male fertile plants,
(b) harvesting in bulk said seed which is formed on said plants of said first planting area,
(c) growing at least a portion of the seed from step (b) in a second planting area in the absence of segregation between the seed derived from said cytoplasmic male sterile plants which exhibit said herbicide tolerance attributable solely to homozygous dominant nuclear genes and said male fertile plants which lack said herbicide tolerance because of the presence of homozygous recessive nuclear genes for such trait, and
(d) contacting prior to pollination substantially all of the plants present in said second planting area with a herbicide which is effective to destroy said plants resulting from seed formed on said male fertile plants of said first planting area, whereby a substantially homogeneous population of a predetermined hybrid variety is formed which resulted from seed formed on said male sterile plants of said first planting area.

1 more element

(a) growing in a first planting area a substantially random population of (1) cytoplasmic male sterile plants which exhibit tolerance to a first at least one herbicide which is attributable solely to homozygous nuclear genes and exhibit tolerance to a second at least one herbicide which is attributable solely to different homozygous nuclear genes, and (2) male fertile plants which are homozygous recessive maintainer plants for said cytoplasmic male sterile plants and which lack said herbicide tolerance to said first at least one herbicide because of the absence of the required nuclear genes for such trait and exhibit tolerance to said second at least one herbicide attributable solely to said homozygous nuclear genes, whereby said cytoplasmic male sterile plants (1) and said maintainer plants are pollinated with pollen derived from said maintainer plants and seed is formed on said cytoplasmic male sterile plants and on said maintainer plants,
(b) harvesting in bulk said seed which is formed on said plants of said first planting area,
(c) growing in a second planting area a substantially random population of plants derived from seed harvested in step (b) together with homozygous dominant fertility restorer plants for said cytoplasmic male sterile plants which exhibit herbicide tolerance to said first at least one herbicide attributable solely to said homozygous nuclear genes and lack tolerance to said second at least one herbicide because of the absence of the required nuclear genes for such trait,
(d) contacting prior to pollination substantially all of the plants present in said second planting area with said first herbicide which is effective to destroy said plants resulting from seed formed on said maintainer plants in step (a) whereby cytoplasmic male sterile plants and restorer plants remain,
(e) pollinating said cytoplasmic male sterile plants and said restorer plants of step (d) with pollen derived from said restorer plants and seed is formed on said cytoplasmic male sterile plants and on said restorer plants,
(f) harvesting in bulk the seed which is formed on said plants remaining in said second planting area,
(g) growing in a third planting area a substantially random population of plants derived from seed harvested in step (f), and
(h) contacting substantially all of the plants present in said third planting area with said second herbicide which is effective to destroy said plants resulting from the seed formed on said restorer plants of step (e), whereby a substantially homogeneous population of male fertile F.sub.1 hybrid plants of a predetermined variety is formed.

5 more elements

An improved process for producing seed capable of forming a predetermined hybrid variety of a crop which is capable of undergoing both self-pollination and cross-pollination comprising:

(a) growing in a planting area a substantially random population of (1) cytoplasmic male sterile plants which exhibit tolerance to a first at least one herbicide which is attributable solely to homozygous nuclear genes, and exhibit tolerance to a second at least one herbicide which is attributable solely to different homozygous nuclear genes, and (2) male fertile plants which are homozygous recessive maintainer plants for said cytoplasmic male sterile plants and which lack said herbicide tolerance to said first at least one herbicide because of the absence of the required nuclear genes for such trait and exhibit tolerance to said second at least one herbicide attributable solely to said homozygous nuclear genes, whereby said cytoplasmic male sterile plants (1) and said maintainer plants are pollinated with pollen derived from said maintainer plants and seed is formed on said cytoplasmic male sterile plants and on said maintainer plants,
(b) harvesting in bulk the seed which is formed on said plants of said first planting area,
(c) growing in a second planting area a substantially random population of plants derived from seed harvested in step (b) together with homozygous dominant fertility restorer plants for said cytoplasmic male sterile plants which exhibit herbicide tolerance to said first at least one herbicide attributable solely to said homozygous nuclear genes and lack tolerance to said second at least one herbicide because of the absence of the required nuclear genes for such trait,
(d) contacting prior to pollination substantially all of the plants present in said second planting area with said first herbicide which is effective to destroy the plants resulting from seed formed on said maintainer plants in step (a) whereby cytoplasmic male sterile plants and restorer plants remain,
(e) pollinating said cytoplasmic male sterile plants and said restorer plants of step (d) with pollen derived from said restorer plants,
(f) subsequently contacting substantially all of the remaining plants present in said second planting area with said second herbicide which is effective to destroy said restorer plants and which is ineffective to destroy cytoplasmic male sterile plants because of said herbicide tolerance attributable solely to said homozygous nuclear genes, and
(g) harvesting seed from said cytoplasmic male sterile plants which is capable of forming F.sub.1 hybrid plants in the substantial absence of seed form said maintainer and restorer plants which initially grew in said seconod planting area.

4 more elements

Dependencies are inferred from the claim text.

Hybridization using cytoplasmic male sterility and herbicide tolerance from nuclear genes

Life of this patent

Hybridization using cytoplasmic male sterility and herbicide tolerance from nuclear genes

Life of this patent

Abstract

Claims70