Tuesday, February 10, 2009

New sunflower is for the birds

Midnight Sun-flower photographed by Bob Van Veldhuizen
After sixteen years of selection, a new oilseed sunflower variety adapted to interior Alaska growing conditions has been announced. Midnight Sun-flower is an open pollinated selection made from a sunwheat variety (a dwarf hybrid sunflower) that was originally planted in 1993. This selection was unofficially released as ‘Midnight Sun-flower’ to local gardeners in spring 2008 as a potential agronomic and horticultural oilseed crop, primarily for the wild birdseed market.

Sunflowers (Helianthus annus L.) are an annual broadleaved plant that can grow 5 to 20 feet tall. They have stout, rough, and hairy stems one to three inches in diameter topped by a seed head that is 3 to 24 inches in diameter. The heads have many small, cross-pollinated flowers surrounded by pointed scales and 40 to 80 yellow rays. Wild sunflowers or horticultural varieties may have multiple branched heads from a single stalk. There are two types of sunflowers that are grown as an agronomic crop. Those that have black or dark brown seed are grown for the oil content, and those with white stripes on the seed grown for the confectionary market. Both the heads and the leaves of sunflowers track the sun during the day and tilt upward at midnight. This phenomenon is called nutation and continues every day until the end of the flowering stage.

About half of the dried weight of sunflower heads is seed. The whole seed contains about 24 to 45 percent oil. Only about 20 to 35 percent oil can actually be expressed from the whole seed. Sunflower oil is obtained by a combination of expressing and solvent extraction. The remaining oil cake meal contains about 35 percent protein, which is used as a livestock feed. Sunflower oil is mostly polyunsaturated and is used in the edible oil market. It also is a semidrying oil that is used in the manufacture of soaps and paints. Whole oil seed is used as a feed for poultry and caged and wild birds. Confectionery seeds are either eaten raw or roasted. In Alaska, sunflowers have been grown on limited acreages off and on for many years, primarily as livestock forage and secondarily as oil and confectionary seed for the local birdseed market.

Starting in 1993, seeds were collected from the earliest maturing heads of a sunwheat variety in the Fairbanks area. These seeds were hand threshed, cleaned, and planted in test plots the following season. This process has been repeated every year since then. Since sunwheats are hybrid varieties and all sunflowers are open pollinated, there was considerable variation in the following year’s crop. However, continued selection for early maturity has resulted in a more uniform, open pollinated sunflower that closely resembles the Canadian Sunola varieties. To date, the plants are quite dwarfish, 20–24 inches tall, and with head diameters of close to 6 inches. It matures 7 to 10 days earlier (an average of 83 days from planting) than the earliest sunwheat varieties and 14–20 days earlier than common sunflower varieties. This produces acceptable yields of around 350–400 lbs/acre, much better than that of the earliest sunwheat varieties. Because this is an open pollinated selection there is still considerable variability among plants.

The heads are mature when the backs of the heads have turned from green to yellow and the bracts have turned brown, which occurs late August to mid-September. Heads will require more drying after harvest to continue ripening the seeds. This can be done by tying a few of the cut stems together and hanging them upside down in a warm dry place for a couple of weeks. The seed can either be left in the heads or they can be threshed from the heads by hand. To do this, use a pair of leather gloves and rub the seeds from the heads into an open container. The heads can then be discarded. Dried heads and cleaned seed can be placed at birdfeeders as a high energy feed for wild birds throughout the winter.

Limited seed will be available through the UAF Alaska Agricultural and Forestry Experiment Station this year. Contact Bob Van Veldhuizen for more information at fnrv@uaf.edu.

For more information on sunflower and other agronomic crop performance trials, see
“Performance of Agronomic Crop Varieties in Alaska, 1978–2002,”
by Robert M. Van Veldhuizen and Charles W. Knight, AFES Bulletin 111 (136 pp), published October 2004 (PDF).

For more information on ornamental sunflower performance, see Annual Flowering Plant Trials (PDF).

by Bob Van Velduizen, SNRAS-AFES research assistant

No comments: