Writer: D'Lyn Ford
LAS CRUCES - After more than a decade of field tests, New Mexico State University scientists have found a way to fill an early summer harvesting void with a new white onion variety that will hit the fresh market while others are still rooted in the ground. They're also ready to release a new red onion - a first for the NMSU.
Named 'NuMex Solano' and 'NuMex Crimson', both are fall-seeded onion varieties planted from late September to early October and harvested from late May to early June. Having two more fall-seeded varieties allows New Mexico producers to fill a crucial market window for grocery and produce sellers.
"We'll be harvesting when there are very few places in the country that can supply onions to the U.S. market," said Chris Cramer, an onion breeder with NMSU's Agricultural Experiment Station in Las Cruces. Currently, New Mexico supplies about 60 percent of the U.S. onions during May and June.
Cramer explained that the 'NuMex Crimson' release has red scales and a flat globe shape. Among its most useful characteristics is resistance to premature seed stalk formation, a process known as bolting. It's also moderately resistant to a damaging fungal disease known as pink root. "What makes it unique is there are very few red onion cultivars that are grown in this area, and it happens to be our first red onion that has been released from the program," Cramer said.
'NuMex Solano' is a white onion that matures three weeks after 'NuMex Crimson'. Solano matures in the third to fourth weeks in June, a time when very few white varieties are harvested. The variety also has a high level of bolting and pink root resistance. "'Solano' has a very round globe shape to it, and excellent pure white scale color," he said. "It tends to be a very hard, very firm onion, which makes it better for shipping."
Onion researchers with NMSU's Agricultural Experiment Station, led by retired onion breeder Joe Corgan, have spent years developing varieties with different maturity dates. Growers need an array of varieties that mature at different times because each variety matures within a one- to two-week window.
"Here in New Mexico, we're harvesting onions from late May all the way to the beginning of August," Cramer said. "You need a number of varieties for that constant window of production." An onion grower in southern New Mexico may plant 20 to 30 different onion varieties to ensure continuous harvest in all three colors - red, white and yellow.
As a biennial crop, onions have a long growing cycle, lengthening the time needed to develop new stock. A single growth cycle takes two years compared to some crops that can have three generations in a year. "When we make the initial cross, it could take 10 to 15 years before the variety is released," he said. For example, Cramer said Corgan's first cross of 'NuMex Crimson' was made in 1989. Work on 'NuMex Solano' began even earlier.
The process is especially long because NMSU scientists make their breeding stock selections under the same growing conditions as producers in the region. In fact, Cramer said, his research teams actually test new onion varieties under more severe conditions than those in a typical grower's field.
For instance, the two new fall-seeded varieties are bolting resistant. To test resistance, Cramer plants them early in the fall, about a month earlier than most growers. "By using that selection pressure, we're developing varieties that are resistant to bolting," he said. Early planting means larger plants that are more susceptible to bolting.
New Mexico's growing season, which ranges from late September through mid-October, allows for three plantings. The fall-seeded onion crop normally matures late in May or early June. A transplanted crop, which is planted in mid-October and then uprooted and replanted in February, usually is ready by late June. Finally, a spring-seeded crop goes in the ground in late January and early February, and matures throughout July, Cramer said.
The first commercial seed for 'NuMex Solano' and 'NuMex Crimson' won't be available for sale until about 2004. NMSU is accepting bids for exclusive production of the two varieties, a change from past releases when any producer could go to the New Mexico Crop Improvement Association and request seed for new varieties.
"The problem was that a lot of growers in New Mexico weren't getting our varieties," Cramer said. "People requesting the seed were only producing the amount of seed that they needed for their own production. Very little was getting to the majority of growers in New Mexico."
As a result, he said, NMSU chose to grant the exclusive rights for one company to produce the two new varieties in hopes that it will have a vested interest in producing and marketing seed for more growers in New Mexico. Prior to the release of the two new onions, NMSU's plant breeders had developed 20 varieties, the first in 1983.
The latest in onion research and marketing will be featured at the annual Onion Conference at the Las Cruces Hilton on March 6. Presenters will review the sweet and processing onion outlook, as well as the current onion marketing order program, which assesses a fee on growers' production to fund promotions aimed at improving markets. New Mexico growers produce 8,000 acres of onions, mostly in Doņa Ana and Luna counties.
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