Cotton Variety Sicot 746B3F A CSIRO-Bred Upland Cotton Claimed as an Invention

This application claims a specific new cotton plant, the variety Sicot 746B3F, together with its seeds, cells, tissues and organs, and the hybrid and transformed plants derived from it. It is filed jointly by Cotton Seed Distributors Ltd and Australia’s national science agency, the CSIRO.

The Problem

Almost all of the world’s cotton comes from a single species, Gossypium hirsutum, commonly called Upland cotton. Growers choose it because it yields heavily, matures early and tolerates a wide range of growing conditions. Its weakness is fibre quality, which is generally rated low to medium against the finer, longer, stronger fibre produced by the alternative species G. barbadense, or Pima. Pima never took over because it yields poorly, needs a long warm season and can be grown in only a narrow band of regions, so it occupies a small share of world cotton area.

That leaves plant breeders with a standing problem. Lint is graded on measures such as fibre length, fibre strength and micronaire, and the objective is to lift those measures inside a high-yielding Upland background rather than paying the yield penalty of switching species. Layered on top is pest pressure. Caterpillar pests, particularly Helicoverpa species, remain one of the major constraints on cotton production worldwide, which is why insect-resistant traits are now standard in Australian crops.

What This Invention Does

The application claims a plant of the cotton variety Sicot 746B3F, or any part, cell, tissue or organ of that plant. The claims extend to cotton seed of the variety, to F1 hybrid plants and seeds produced using the variety as a parent, and to plants and seeds produced by transformation of the variety along with their progeny.

The name itself carries information. Sicot is the naming prefix used by the CSIRO cotton breeding program, and the B3F suffix identifies the stacked trait package the variety is sold with: three-gene Bacillus thuringiensis insect protection against Helicoverpa and related caterpillars, combined with herbicide tolerance for in-crop weed control. What the patent claims, though, is not the traits. It is the plant itself, the particular genetic combination the breeding program assembled, which is what separates this variety from every other line on the market.

Key Features

• The variety as such. A plant of the cotton variety Sicot 746B3F is claimed, together with any part, cell, tissue or organ of it.
• Seed coverage. Cotton seed of the variety falls within the scope of the claims.
• Hybrid progeny. F1 hybrid cotton plants and seeds produced using the variety as a parent are included.
• Transformed plants. Plants and seeds produced by transformation of the variety, and the progeny of those plants, are covered.
• Upland species base. The variety sits within Gossypium hirsutum, the species that supplies the overwhelming majority of world cotton.
• Stacked trait package. The B3F designation reflects three-gene Bt insect protection combined with herbicide tolerance.

Who Is Behind It

The applicants are Cotton Seed Distributors Ltd, an Australian-owned business based at Wee Waa in northern New South Wales that has supplied elite cotton planting seed to the Australian industry since 1967, and the Commonwealth Scientific and Industrial Research Organisation, the national science agency headquartered in Canberra. The named inventor is Warwick Nigel Stiller, a long-serving breeder in the CSIRO cotton program whose name appears on the Sicot variety applications. This application is a divisional of Australian application 2023258381.

Why It Matters

Cotton is one of Australia’s larger agricultural exports, and Australian growers plant almost entirely Australian-bred varieties. That is a direct result of the long-running partnership between CSIRO, which does the breeding, and CSD, which multiplies and distributes the seed. Australian cotton yields sit among the highest in the world, and the varietal pipeline is a large part of the reason.

New plant varieties in Australia can be protected under plant breeder’s rights as well as under the patent system, and breeders frequently use both. A patent claiming the variety, its seed and its progeny gives control over propagation and over use of the variety as a parent in further breeding, which is the mechanism by which a public research agency recovers its investment and funds the next round of varieties.

Related Concepts

• Gossypium hirsutum – the Upland cotton species this variety belongs to.
• Plant breeding – the discipline that produced the variety.
• Bt cotton – the insect protection technology behind the B3F designation.
• Micronaire – one of the fibre quality measures cotton breeders select on.
• Plant breeder’s rights – the alternative Australian route for protecting a new variety.
• Cotton production in Australia – the industry this variety is bred for.

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AU 2026202042 was published in the Australian Official Journal of Patents on 2 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.