[Pollinator] NYTimes Article: Growers Yearn to Be Free of Mandarin Seeds

[Jennifer Tsang]

http://www.nytimes.com/2007/03/14/dining/14seed.html?em
<http://www.nytimes.com/2007/03/14/dining/14seed.html?em&ex=1174017600&en=25
c82399316ffb8a&ei=5087%0A> &ex=1174017600&en=25c82399316ffb8a&ei=5087%0A

 

March 14, 2007


Growers Yearn to Be Free of Mandarin Seeds 


By DAVID KARP

Maricopa, Calif.

A SWARM of bees can get anyone worked up, although most people would not
think to file a lawsuit in retaliation.

Last April, though, California's largest citrus grower threatened to sue
beekeepers, accusing them of letting their insects "trespass" on mandarin
groves. 

The growers were not afraid of being stung, they were afraid that the bees
would pollinate their trees, something farmers usually want bees to do. But
these trees in the San Joaquin Valley were planted to bear seedless fruit,
and pollination would create seeds. 

This spring a citrus growers trade association will be lobbying the state
legislature for a Seedless Mandarin Protection Act that would establish
"no-fly zones" of two miles for hives around designated orchards.

If the response seems unusual it's because of what is at stake: seedless
mandarins fetch three to four times the price of seeded ones, according to a
2005 study. The acres in California planted with mandarins, mostly seedless
varieties, have grown to 27,000 from 10,000 in 1998. In 10 years it will
probably be hard to find mandarins, also known as tangerines, with seeds.

"It's becoming impossible to market mandarins with a high level of seeds,"
said Etienne Rabe, a manager for Sun Pacific, a large grower, as he watched
harvesters clip fruit at a huge planting near Bakersfield.

Tom Mulholland, who grows 400 acres of mandarins southeast of Fresno, was
even more dismissive of seeded varieties. "Push 'em out, bye-bye," he said.
"That's where your low prices are going to be." 

As growers learned starting 70 years ago with seedless grapes and more than
a decade ago with seedless watermelons, shoppers will pay for convenience.
To feed the demand for fruit with less mess, farmers and scientists have
been chasing new varieties and developing new technologies. 

But the process began long ago, when growers found natural mutations of
citrus fruits with few or no seeds, like navel oranges and Persian limes,
which they propagated by grafting. A few seedless mandarins have been around
for more than a century, notably the early-season satsumas, but they were
limited in season and not as addictively sweet and richly flavored as the
best varieties, like clementines.

Originally, clementines were seedy, and required pollination by bees to bear
regular crops. In the 1960s California researchers discovered that by
applying a spray at bloom, simulating the growth hormones naturally secreted
by seeds, farmers could obtain good harvests of seedless clementines. Bees
became undesirable.

Spanish scientists improved this technique, and in the 1980s and 1990s
seedless Spanish clementines conquered markets in Europe and the eastern
United States.

California growers saw this success, and in the late 1990s rushed to plant
clementines, mostly in the San Joaquin Valley citrus belt, from south of
Bakersfield to Fresno.

They also placed big bets on a clementine-like variety of seedless mandarin,
found in Morocco in the 1980s, with the ungainly name of W. Murcott Afourer.
A hybrid of Florida's Honey Murcott tangerine, possibly with a clementine,
it has thin, easily peeled skin, a deep orange color and very good flavor.
Ripening after clementines, from late January to March, and producing
abundantly without bees or hormones, it quickly became the hottest new
citrus variety. 

A freeze in mid-January destroyed about half of the state's late-season
mandarins, but as shipments soar in the next few years "there's going to be
a head-on clash" with Spanish exporters, Mr. Rabe said. 

But clementine and W. Murcott trees dependably produce seedless fruit only
when grown in isolated blocks. If they are not, the presence of bees becomes
an issue. 

Most growers underestimated how much buffer zone they needed around
plantings to keep bees from bringing pollen from nearby seedy citrus. In
pressing for legislation, California growers are again following Spanish
farmers, who in 1994 got their government to bar beekeepers from putting
hives near their plantings during bloom.

Hives could be moved to other groves, or beekeepers could feed their
colonies, said Joel Nelsen, president of California Citrus Mutual, a growers
association.

Something has to be done, he said. "As more mandarin plantings start
bearing, the situation's going to explode," he added.

Pollination by bees is crucial to many California crops, including almonds,
stone fruit and melons, and while the law would let this continue,
beekeepers vehemently object to the restrictions. They have recently
sustained grave losses because of a mysterious syndrome called colony
collapse disorder.

"It'd be a devastating loss of the locations needed to keep bees healthy,"
said Joe Traynor, a bee consultant in Bakersfield.

A partial solution for this problem - an irradiated version of W. Murcott
that never develops seeds, even when cross-pollinated by bees - has been
developed by Mikeal L. Roose and Tim Williams, citrus breeders at the
University of
<http://topics.nytimes.com/top/reference/timestopics/organizations/u/univers
ity_of_california/index.html?inline=nyt-org>  California at Riverside. In
1996 they irradiated W. Murcott budwood sticks (stems used for grafting) to
rearrange the chromosomes to cause sterility.

While many resulting trees had fatal mutations, one, now called Tango, was
virtually identical to the original W. Murcott yet averaged only one seed in
five fruits. 

Nurseries started propagating Tango in June, and have orders for millions of
trees.

Using irradiation to breed mutations in citrus is not new - Richard Hensz
developed the deep-red Star Ruby and Rio Red grapefruits using this
technique, starting in 1959. But Dr. Roose and Mr. Williams have undertaken
a far-reaching program trying to rid the seeds from 63 varieties of citrus.
Although most are mandarins, their 6,000 experimental trees also include
oranges, tangelos, lemons and grapefruits.

On a recent visit to his test plots in Riverside, Calif., Mr. Williams
offered samples of a dozen selections, identical to the parents except that
they averaged only one to three seeds instead of 10 to 30.

(There's a debate among growers over what is "seedless." A consortium of
growers that markets 90 percent of California-grown clementines and W.
Murcotts under the name Cuties allows no more than 15 fruits with seeds out
of 100. Other growers say that is too strict.)

The original Daisy mandarin may be the most delicious citrus, but hardly
anyone has planted it because it is so seedy. Mr. Williams said the
University of California might release irradiated Daisy and other low-seeded
varieties late next year.

Many researchers around the world are irradiating citrus. Florida, still the
leading producer of mandarins in the United States, cannot grow high-quality
clementines in its climate, and has lagged in introducing seedless
varieties. But the United States
<http://topics.nytimes.com/top/reference/timestopics/organizations/a/agricul
ture_department/index.html?inline=nyt-org>  Department of Agriculture and
the University of Florida
<http://topics.nytimes.com/top/reference/timestopics/organizations/u/univers
ity_of_florida/index.html?inline=nyt-org>  have several promising irradiated
selections, including low-seeded versions of the state's three major
commercial mandarins. One, Fallglo, may be released within a year; after
that it will take about five years for fruit to be sold commercially.

Scientists also are breeding new seedless varieties, mainly by hybridizing
trees with three sets of chromosomes, rather than the normal two. That
genetic imbalance causes the fruits to be seedless. Five years ago the
University of California introduced three such triploid mandarins, of which
some 200 acres have been planted, and University of Florida breeders are
evaluating 12,000 triploid mandarins.

"Triploids are the future of seedlessness," said Jude W. Grosser, a citrus
breeder at the University of Florida.

He also induces mutations by regenerating a tree from a single cell. One
result bears seedless Valencias, the world's leading juice orange, in a
version more suitable for eating fresh. He said it would probably be
introduced in three years.

An experimental method called cybridization transfers a gene for sterility
into seedy varieties, rendering them seedless more efficiently than the
shotgun approach used in irradiation. 

While all these techniques involve advanced biotechnology, none are
considered "genetic modification" for regulatory purposes, Dr. Grosser said.
And there has been no evidence that any of them have compromised flavor or
healthfulness.

The success of all these methods may show that, paradoxically, the best way
for a mandarin to proliferate is to be sterile.

 

 

Jennifer Tsang
Coevolution Institute <http://coevolution.org> 
423 Washington St. 5th Fl.
San Francisco, CA 94111-2339
T: 415.362.1137

F: 415.362.3070

www.nappc.org

www.pollinator.org

 

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