As we in the Northern Hemisphere move into winter, it can be helpful to consider summer flowers from time to time. An iconic summer flower that we’ve discussed in the past is the sunflower, Helianthus annuus.
Three recent patents from Dow Agrosciences offer innovations in the area of sunflower breeding, combining traditional plant breeding across multiple generations, tissue culture, and transgenic manipulation of the plants’ genome.
Sunflower (Helianthus annuus L.) now ranks second among all oilseed crops in the world as a source of edible vegetable oil.
Food uses of sunflower include snack foods, cooking mediums and salad oils. Whole achenes are an important component of bird and other small animal feeds. Sunflower silage has utility as a livestock feed.
Sunflower oil is also used in the manufacture of margarine, soap, pharmaceuticals, shortening, lubricants and as a source for biodiesel fuels.
Sunflower hulls can be pressed into logs for use in the fireplace and cooking stoves.
Sunflower hybrids can be classified into two broad categories: confection (non-oil) and oil types.
Confection sunflower seeds may be further divided into three classes: in-shell, kernel and birdseed. In-shell seed refers to larger sunflower seeds which may be roasted, salted and packaged for human consumption. Kernel seed refers to medium sized seeds which may be dehulled and also packaged for human consumption. Smaller seed may be sold in birdseed markets. Oil-type sunflower seed is richer in oil and therefore better suited to the production of sunflower oil and is used to produce ingredients for animal feed.
Oil sunflower hybrids may be further divided into three classes: linoleic (regular oil type), NuSun (mid-oleic), and high oleic.
A third category of sunflower seed referred to as hybrid seed has attributes of both confection and oil type sunflowers.
Sunflowers have both male and female organs on the same flower; sunflower breeding techniques take advantage of the plant’s ability to be bred by both self-pollination and cross-pollination.
Dow Agrosciences’ patents teach us much about sunflower breeding, improvements, and methods:
Why Breed Plants?
A Little Botany
Because sunflower has both male and female organs on the same flower, sunflower breeding techniques take advantage of the plant’s ability to be bred by both self-pollination and cross-pollination. Self-pollination occurs when pollen from the male organ is transferred to a female organ on the same flower on the same plant. Self-incompatability is a form of infertility caused by the failure of sunflower plants with normal pollen and ovules to set seed due to some physiological hindrance that prevents fertilization. Self-incompatability restricts self-pollination and inbreeding and fosters cross-pollination. Cross-pollination occurs when pollen from the male organ on the flower of one plant is transferred to a female organ on the flower on a different plant.
Add Some Genetics
When two different, unrelated inbred sunflower parent plants are crossed to produce an F1 hybrid, one inbred parent is designated as the male, or pollen parent, and the other inbred parent is designated as the female, or seed parent. Because sunflower plants are capable of self-pollination, hybrid seed production requires elimination of or inactivation of pollen produced by the female parent to render the female parent plant male sterile. This serves to prevent the inbred sunflower plant designated as the female from self-pollinating. Different options exist for controlling male fertility in sunflower plants such as physical emasculation, genetic male sterility, cytoplasmic male sterility and application of gametocides. Incomplete removal of male parent plants from a hybrid seed production field before harvest provides the potential for unwanted production of self-pollinated or sib-pollinated seed which may be unintentionally harvested and packaged with hybrid seed. [note: A plant is sib-pollinated (a type of cross-pollination) when individuals within the same family or line are used for pollination (i.e. pollen from a family member plant is transferred to the stigmas of another family member plant).
A seed of sunflower inbred line …
A method for producing an inbred sunflower plant …
A method of introducing a desired trait into sunflower inbred line …
A method for producing an inbred sunflower plant …
A method for producing a CN1703-derived sunflower plant … [CN1703 is the designation of the specific sunflower line to be produced via this invention]
A method for regenerating a sunflower plant … [using tissue-culturing methods]
A method for developing a sunflower plant in a sunflower plant breeding program
These claims, and their dependents, don’t just apply standard plant breeding and tissue-culturing methods. They also provide for genetic modification of the sunflowers that form this specific line. In particular, transgenic material is introduced that “comprises a gene conferring upon the sunflower plant tolerance to a herbicide” (claim 51) or “comprises a gene conferring upon the sunflower plant insect resistance, disease resistance or virus resistance” (claim 53).
Thus, the sunflower line produced by this invention (and the separate lines produced via the ‘501 and ‘502 patents) is a GMO plant intended to resist herbicides, insects, disease, or plant viruses.