Posts Tagged: seed

Peel back the layers and see what the onion is all about

For crying out loud, who doesn't love an onion? Whether you enjoy them in burgers, broths, sandwiches or soups, or deep-fry them as onion rings or serve them with liver, they're to die for and to cry for.

The average American eats 21 pounds of onions per year. Indeed, our appetite for the fresh green as well as yellow, red, and white bulb onions is increasing in the United States, up 70 percent from several decades ago. A valued crop generating $1.2 billion a year, the onion currently ranks No. 2 in the vegetable industry, right behind the potato. Yellow onions account for nearly 90 percent of all onion consumption, followed by red and white varieties.

Onions, cultivated for more than 5,000 years, are one of the most versatile vegetables. They are found in every ethnic cuisine from breakfast to lunch to dinner and are rich in vitamin C and fiber. As Julia Child noted, “It's hard to imagine civilization without onions.”

With a thriving onion industry comes a “crying” need for onion seed planting stock; onions have to flower and set seed. California is a major worldwide supplier of onion seed, with growers producing about 3,000 acres of hybrid onion seed worth about $12 million, and generating an additional $40 million annually in subsequent retail sales. The major growing areas in our state are the Imperial Valley and Colusa County.

Seed companies from around the world contract with growers here in California to produce hybrid onion seed. The many different varieties include red, yellow and white bulbs, including types that are adapted to different day lengths from our northern to southern hemispheres. Growers plant onion bulbs or seedling transplants in late summer with distinct male (male fertile) and female (male sterile) onion lines in the same field. Generally, the field ratio is one row of males for every three female rows and they're tough to tell apart from a distance, but males produce pollen.

In Northern California, flowering occurs for a short four to five weeks the following May and June, with scapes from each bulb producing a white umbel with multiple florets. Growers rely on honey bees for cross pollination, that is moving the pollen from male to female rows. Each acre usually includes 10 to 12 hives. Native bees are also important for pollinating onion flowers, as are flies. No pollinators? No onion seed production.

Thankfully, there are few pests of onion seed, although the recent introduction of the iris yellow spot virus vectored by the onion thrips has resulted in increased insecticide use to control this potentially devastating pest and disease. Recent research by UC Cooperative Extension specialists in Yolo County and UC Davis, however, documented that more than three insecticide sprays applied pre-bloom per year can reduce honey bee visitation to flowers. Insecticides may also interfere with the ability of female flowers to receive pollen; that is, sprays applied near to bloom time can lead to overall lower pollen germination. As a result, growers are now careful to minimize insecticide use in onion seed production fields to ensure good pollination and yields.

Likewise, growers must carefully manage their irrigation water to ensure that the onion flowers produce good nectar rewards to maximize honey bee visitation. Honey bees are attracted to flowers with ample nectar production. Fields that are too wet or too dry show reduced floral nectar rewards and a decrease in honey bee visitation.

After cross-pollination occurs and seeds are set, growers knock down the male rows to remove them to facilitate harvesting of female lines and ensure purity of the seed. Once the female umbels dry down, they are harvested primarily by hand, placed on tarps to fully dry, and then the tiny black seeds from the florets are mechanically threshed with a combine, and cleaned and packaged for retail sales.

Although a small acreage crop in California, onion seed is an important specialty crop that significantly boosts our agricultural economy, as well as providing needed seed for farmers throughout the world.

But, before you can slice them, chop them or dice them, you have to grow them and our California growers do it best.

Additional information on onion seed production can be found at:

http://ceyolo.ucanr.edu/Custom_Program/Seed_Crop_Production/Onion_Seed_Production/

 

Onion umbel with seeds

Sunflower seeds are boosting California’s ag economy

Sunflower seeds are a healthy snack, a salad garnish, and a baseball dugout icon. But how much do you know about the state’s hybrid seed production that results in the global planting and growing of oil and confectionary-type sunflower seeds?

Do you know that the Sacramento Valley produces about 25 percent of the world’s hybrid planting sunflower seeds? We grow some 47,000 acres of this crop, valued at about $70 million (2012 County Crop Reports).

Even better news is that the hybrid sunflower seed production industry is growing, sparked by the demand for our high quality seed and the increased interest in sunflower oil worldwide. In 2007, for example, the value of California’s sunflower seed crop totaled $22 million on 27,000 acres. Fast forward to today and we see a 70 percent increase in acreage and more than a three-fold increase in value. Additionally, the industry reports millions of dollars in seed sales to markets around the world including the Midwestern states as well as the four largest producers of sunflower oil: Ukraine, Russia, European Union, and Argentina.

The sunflower (Helianthus annuus) is native to North America; the Native American Indians prized it as an important, high-energy food source. Indeed, sunflower oil is a healthy choice; it is light in taste, supplies more vitamin E than any other vegetable oil, and delivers low levels of saturated fat. Sunflower oil is also stable at high cooking temperatures, rendering it favorable to the food processing industry.

Production of hybrid sunflower seeds involves planting male and female (male sterile) lines in the same fields, usually alternating with six rows of females and two rows of males. Males generally possess multiple flowers on a stock, compared to the single composite female flower. Honey bees, usually two colonies per acre, move the pollen from the male to female lines. Native solitary bees (especially sunflower bees) are also important in sunflower seed production, not only because of their pollination but because their presence increases honey bee activity, causing greater dispersement between male and female lines.

After pollination, when the seeds are set, growers remove the male rows to prevent contamination with female rows. After the sunflower stocks naturally dry down, the hybrid planting seed is harvested with yields averaging 1,400 pounds per acre and 40-45 percent percent oil content, depending on the variety.

Compared to open pollinated varieties, hybrid planting seed from controlled crosses of male and female lines result in higher yields and oil content. The plants also display better disease resistance, a high degree of self-compatibility (reducing the need for bee cross-pollination), and more uniformity in height and moisture content at maturity, which facilitates harvest.

It’s crucial to maintain field isolation between different hybrid sunflower varieties so that the seed produced remains pure to the desired cross. As a result, growers plant different sunflower seed varieties at least 1-1/4 miles apart or they separate fields in time so that they bloom at different times in the season, thus preventing pollen drift. volunteer sunflowers from the previous year, wild sunflowers, and sunflower varieties blooming in backyard gardens pose risks to hybrid sunflower seed production. Roguing prior to bloom is important when nearby production fields are blooming.

Do you know that sunflower seed production has few pest or disease problems? Sunflower head moth, a native caterpillar pest, can attack the seed heads as well as occasional flocks of birds (starlings, blackbirds, and finches) triggering yield and quality losses.

As the result of industry and research efforts, along with our near perfect weather for seed production with hot, dry summers and cool nights, the Sacramento Valley is known throughout the world as a premier location for sunflower breeding, variety development, and seed production.

In the summertime, the brilliant golden colors turn fields in the Sacramento Valley into Vincent Van Gogh-like paintings. Sunflowers are also fun to watch because in the bud stage they track the movement of the sun across the horizon. Once the flower opens it faces east toward the morning sun, which may help prevent the sun-scalding of seeds.

So, whether you like to cook with sunflower oil, snack on sunflower seeds, use them as a salad garnish, or watch your favorite baseball players crack them between innings, sunflowers pack a major economic agricultural wallop that begins right here in the Sacramento Valley. Who knew? Now you do.

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