US 4,658,085 AGranted

Hybridization using cytoplasmic male sterility, cytoplasmic herbicide tolerance, and herbicide tolerance from nuclear genes

AssigneeUniversity of Guelph

InventorsWallace D. Beversdorf, Lawrence R. Erickson, Ian Grant

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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 cytoplasmic herbicide tolerance (i.e., to a Type A herbicide) and tolerance to a different herbicide attributable solely to nuclear genes (i.e., to a Type B herbicide) are the key plants for use in the present process. The maintainer and restorer plants exhibit tolerance to different herbicides (i.e., to either a Type A herbicide or a Type B herbicide). The economical bulk planting of the parent plants is made possible during each step of the process. For instance, cytoplasmic male sterile plants, plants resulting from the self-pollination of a maintainer, and restorer plants can be grown in a substantially random population, with the self-pollinated maintainer plants being destroyed by an appropriate herbicide prior to pollination, and the self-pollinated restorer plants being destroyed by an appropriate herbicide immediately following pollination or in the subsequent generation. 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.

Claims79

Dependent claims

An improved process for producing a substantially homogeneous population of plants of a predetermined hybrid variety of crop which is capable of undergoing 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 cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to at least one Type B herbicide which is attributable solely to homozygous dominant nuclear genes, and (2) male fertile plants which are homozygous recessive maintainer plants for said cytoplasmic male sterile plants and which lack said cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to said at least one Type B herbicide attributable solely to said homozygous dominant 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 cytoplasmic herbicide tolerance to said at least one Type A herbicide and lack tolerance to said at least one Type B herbicide because of the absence of the required dominant nuclear genes for such trait,
(d) contacting prior to pollination substantially all of the plants present in said second planting area with a Type A 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 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 a Type B 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 first planting area a substantially random population of (1) cytoplasmic male sterile plants which exhibit cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to at least one Type B herbicide which is attributable solely to homozygous dominant nuclear genes, and (2) male fertile plants which are homozygous recessive maintainer plants for said cytoplasmic male sterile plants and which lack said cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to said at least one Type B herbicide attributable solely to said homozygous dominant 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 cytoplasmic herbicide tolerance to said at least one Type A herbicide and lack tolerance to said at least one Type B herbicide because of the absence of the required dominant nuclear genes for such trait,
(d) contacting prior to pollination substantially all of the plants present in said second planting area with a Type A 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 a Type B 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 which exhibit tolerance to each of said Type A and Type B herbicide in the substantial absence of seed from said maintainer and restorer plants which initially grew in said second planting area.

4 more elements

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 cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to at least one Type B herbicide which is attributable solely to homozygous nuclear genes, and (2) male fertile plants which are homozygous recessive maintainer plants for said cytoplasmic male sterile plants and which exhibit said cytoplasmic herbicide tolerance to at least one Type A herbicide and lack said tolerance to said at least one Type B herbicide because of the absence of the required nuclear genes for such trait, 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 lack said cytoplasmic herbicide tolerance to said at least one Type A herbicide and exhibit tolerance to said at least one Type B herbicide because of the presence of said required homozygous nuclear genes for such trait,
(d) contacting prior to pollination substantially all of the plants present in said second planting area with a Type B 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 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 a Type A 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 first planting area a substantially random population of (1) cytoplasmic male sterile plants which exhibit cytoplasmic herbicide tolerance to at least one Type A herbicide and exhibit tolerance to at least one Type B herbicide which is attributable solely to homozygous nuclear genes, and (2) male fertile plants which are homozygous recessive maintainer plants for said cytoplasmic male sterile plants and which exhibit said cytoplasmic herbicide tolerance to at least one Type A herbicide and lack said tolerance to said at least one Type B herbicide because of the absence of the required nuclear genes for such trait, 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 lack said cytoplasmic herbicide tolerance to said at least one Type A herbicide and exhibit tolerance to said at least one Type B herbicide because of the presence of said required homozygous nuclear genes for such trait,
(d) contacting prior to pollination substantially all of the plants present in said second planting area with a Type B 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 and seed is formed on said cytoplasmic male sterile plants and on said restorer plants,
(f) subsequently contacting substantially all of the remaining plants present in said second planting area with a Type A herbicide which is effective to destroy said restorer plants and which is ineffective to destroy said 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 from said maintainer and restorer plants which initially grew in said second planting area.

4 more elements

Dependencies are inferred from the claim text.