Hybridization process utilizing a combination of cytoplasmic male sterility and herbicide tolerance

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 cytoplasmic herbicide tolerance, and (2) male fertile plants which are capable of pollinating said cytoplasmic male sterile plants and which lack cytoplasmic herbicide tolerance, whereby said cytoplasmic male sterile plants (1) are pollinated with pollen derived from said male fertile plants (2),
• (b) contacting substantially all of the plants present in said growing area following said pollination with a herbicide which is effective to destroy said male fertile plants and which is ineffective to destroy said cytoplasmic male sterile plants, and
• (c) harvesting seed from said cytoplasmic male sterile plants which is capable of forming said hybrid plants in the substantial absence of seed from said male fertile plants which initially grew in said planting area.

A Brassica napus seed product consisting of a substantially homogeneous assemblage of seeds which upon growth yield rape plants which exhibit a combination of cytoplasmic male sterility and cytoplasmic atrazine tolerance when applied as a foliar spray at a rate of 2 kilograms per hectare.

A Brassica napus seed product consisting of a substantially homogeneous binary admixture of seeds which upon growth yield

• (1) a first rape plant component which exhibits cytoplasmic male sterility and cytoplasmic atrazine tolerance when applied as a foliar spray at a rate of 2 kilograms per hectare, and
• (2) a second rape plant component which is capable of pollinating said first rape plant component, is a homozygous recessive maintainer for said cytoplasmic male sterility of the first rape plant component, and which lacks atrazine tolerance when applied as a foliar spray at a rate of 2 kilograms per hectare.

A Brassica napus seed product consisting of a substantially homogeneous binary admixture of seeds which upon growth yield

• (1) a first rape plant component which exhibits cytoplasmic male sterility and cytoplasmic atrazine tolerance when applied as a foliar spray at a rate of 2 kilograms per hectare, and
• (2) a second rape plant component which is capable of pollinating said first rape plant component, is a homozygous dominant fertility restorer for said first rape plant component, and which lacks atrazine tolerance when applied as a foliar spray at a rate of 2 kilograms per hectare.