Vegetable breeding (3),

Broccoli: Focus on the Seed

Inspired by Johns Hopkins colleagues who found that sprouted broccoli seed has about 10 times more glucoraphanin than the plant itself does, Farnham has expanded his work to include the seed.

He notes that most broccoli seed is expensive. "It's a crop that's mainly grown for food, not seed. But this is a new approach. We're developing inexpensive seed sources that will provide high glucoraphanin levels. To accomplish this, we'll wind up breeding a different type of broccoli.

"The new focus doesn't mean that we're not interested in broccoli as a vegetable food," Farnham says. "But we are looking for new uses of the crop."

Recently, he and colleagues produced relatively high-glucoraphanin broccoli through crossing types high in glucoraphanin with ones low in the compound. Farnham's team has also produced and identified broccoli plants very high in glucoraphanin that can successfully pollinate without the help of insects.

Currently, Farnham is working with the private sector to test these self-pollinating lines for seed production.

He adds that USVL's overall glucoraphanin research may one day lead to extracting the compound from broccoli for pharmaceutical purposes--something he says wouldn't be cost-effective from the plant, but might be possible from the seed.

In the meantime, Fery is developing "double-green" peas--those whose hues come from combining two unrelated genes.

Peas: A Perfect Shade of Green

"When it comes to these peas, green's the thing," says Fery. "You want just the right shade of green--not too dark--and the ability to maintain that color." Specifically, Fery is integrating these green genes into a pinkeye-type southernpea. "This pea is the mainstay of the southernpea industry," he says.

Varieties of southernpea that stay green when dry have long garnered interest from plant breeders. Frozen-food processors like the persistent green seed trait because it greatly enhances the appearance of their product, Fery explains.

Double-green varieties have the gc gene and a gene called green testa (gt). The gc gene was identified in 1993 as being responsible for the green cotyledon trait in another USVL release, the southernpea cultivar Bettergreen. At harvest, dry seeds still have their fresh green color. The gt gene, discovered in 1974 at Auburn University, imparts a green seed-coat color that persists in the dry seed.

Fery says that while he and colleagues have developed several superior pinkeye types of advanced breeding lines containing the double-green seed trait, much seed-multiplication and evaluation work lies ahead before a cultivar can be released.

That's why USVL has established a cooperative research and development agreement (CRADA) with Western Seed Multiplication, Inc., of Wadmalaw Island, South Carolina, for completing the work and bringing this new generation of pea cultivars to market.

USVL and Western Seed, a major grower of cowpea seed stock for the food-processing industry, previously collaborated to develop Charleston Greenpack, which is now the leading southernpea cultivar being packed by frozen-food producers.

Under the present CRADA, the new breeding lines will be evaluated for commercial-processing suitability and their resistance to the blackeye cowpea mosaic virus.

Watermelon: The Call of the Wild

Looking ahead, USVL researchers see important developments on the horizon for watermelon (Citrullus lanatus).