by Anna Charny
Exotic: originating in a foreign country or having a strange or bizarre
allure, beauty or quality.
Of the estimated 300,000 plant species worldwide, only a minute fraction
serves as food, medicinal and industrial sources. Most of these crops were
domesticated thousands of years ago. The remainder comprise a vast,
unexplored frontier bursting with possibility. Israeli scientists are now
turning to the desert and semi-arid areas in search of promising plants for
cultivation. They are also interested in initiating cooperative research
projects between Israel and seed source countries. Pipe dreams, destined to
disappear in shifting desert sands? Maybe. Maybe not.
A stunning variety of new and exotic fruits in enticing colors and unusual
shapes may soon find its way to Israeli tables and export, providing Prof.
Yosef Mizrahi and colleagues Dr. Avinoam Nerd and Dr. Genady Goldman get
their way.
Mizrahi, of Ben-Gurion University's Life Sciences Department and the
Institutes for Applied Research and an expert in desert agriculture, views
various desert fruit crops, including the poetically sounding dragon pearl
fruit, pitaya and marula, as significant potential boosters for Israel's
export market, and other countries with arid environments. "The future of
Israeli agriculture lies in the desert," he says. "Growing urbanization,
increasing pollution, limited water resources and expensive labor will
eventually drive agriculture into the desert and to hardy crops with low
water and labor requirements."
Changing climatic conditions, including global warming, also dictate the
need for further developing arid-zone crops. Cacti show great adaptability
to infertile soils and tolerate temperatures of up to 50-55 degrees
Centigrade. They can therefore provide diversification and sustainable
agricultural systems in dry, infertile lands where common crops fail. "For
years, the Israeli agricultural approach has been bent on forcing common
crops into desert areas, often with impressive success," says Mizrahi. "Yet
why not take the easy route? Why not explore desert areas in search of
native promising fruits, and then domesticate them?"
Mizrahi's awareness of the potential fortune in wild desert fruits and nuts
waiting to be commercially explored began back in the 1980s when working
with American ethnobotanist, Dr. James Aronson. In 1984 he set out to
distant shores, including Mexico, Central America, Morocco and Sub-Tropical
Africa, in search of rare and wild fruits for experimental domestication.
His journeys took him to the Kalahari Desert in Botswana, where native
Bushmen introduced him to the monkey orange, a sweet and sour pomelo-sized
fruit, and to Sicily, where he learned about the cactus pear's power for
treating prostate disease from the local elderly population. "When you get
old and begin to have problems, add the plant's flowers to your tea and you
will be young again," they promised with laughing eyes. He returned with 40
different species, generally unknown to the world market, and planted them
in five desert sites, each differing in climate, soil and water conditions.
Experimental stages focused on assessing the species' survival, growth,
yields and quality, followed by market evaluation.
Current Results
Promising "contenders" include five different pitaya species from Central
and South America, and the white sapote, hailing from Mexico. They also
include the marula, a white, highly aromatic sweet and sour fruit, and the
cactus pear, known for its juicy flesh, that is, however, well protected by
a formidable prickly covering.
Crawling Pitaya (Hylocereus undatus)
The pitaya belongs to the climbing cacti family, an epiphytic group native
to the forests of Mexico, northern South America and Central America.
Epiphytic plants, common in tropical rain forests, lack soil roots and live
in the canopy, supported by other trees and vines. Their aerial roots form a
tangled network through which they obtain water and nutrients from falling
organic debris.
Interestingly, native crawling pitayas do not possess the traditional
large-leafed, rich green features of tropical plants, despite the fact that
they live in a virtual Garden of Eden, blessed by up to four meters of rain
per year. The reason? Because of their epiphytic nature, they are often
subjected to water stress and have thus evolved the common adaptations of
arid zone plants: distinct cacti, often spiny, thick stems. Fortunately,
these features confer a significant advantage for arid zone farmers.
Climbing cacti require a mere tenth the amount of water of any known
domesticated crop!
Yet what about the fruit? The crawling pitaya, also known as eden or dragon
fruit, appears to have inherited the best of both worlds. It boasts
luscious, red, exotically tasting fruit that wouldn't be out of place in the
most magnificent, rainbow-colored tropical environment. In addition, the
fruit is spineless and possesses protracted shelf life.
Following extensive examination of parent plant characteristics, Mizrahi's
team has created over 1,000 hybrids. As these species are spread out
geographically and thus do not meet in nature, hybridization opens up a wide
range of opportunities. Some resulting hybrids may exceed the quality of
available wild germplasm, yielding superior, previously non-existing fruit.
Last year marked the first export of dragon fruit with 10 tons sold to
Europe. This year, placed orders are rapidly reaching the 40 ton mark.
Apple Cactus (Cereus peruvianus)
The apple cactus is another promising pitaya, originating in Argentina and
Peru. It is extremely hardy, requiring modest irrigation and soil conditions
and able to withstand extensive heat and sunlight.
"Do it in the Dark"- the Cacti's Secret Card
Probably the most unusual and commercially beneficial cacti characteristic
is their photosynthetic pathway, termed CAM (crassulacean acid metabolism).
In contrast to other plants that open their stomata during the day to absorb
the CO2 needed for photosynthesis, cacti stomata open at night, thereby
significantly reducing water loss to transpiration. Yet photosynthesis can
only begin with daylight. What does the plant do with the accumulating CO2?
Acid levels rise at night, as the incoming CO2 is stored in the form of
malic acid. With daylight, the acid is converted back to C02 and the
photosynthetic glucose production line begins.
Interestingly, the apple cactus also blooms at night, following a pattern
exhibited by many desert species, which cater to their pollinator's
nocturnal lifestyle designed to avoid intense daylight heat. Yet the romance
is brief - the apple cactus blooms for only one night per year, and so
requires immediate pollination.
While CAM plants are generally slow growers, the annual productivity of
certain irrigated CAM crops (including the cactus pear, agave and pineapple)
exceeds that of nearly all cultivated non-CAM plants. This feature
demonstrates the high potential of future cacti cultivation.
Cactus Pear (Opuntia spp.)
The cactus pear is already an established crop in Mexico, Italy, Israel and
South America. Opuntia stems are very popular in Mexico where they are known
as nopalito. The vegetable, which is usually roasted or cooked after the
spines are removed, is used in salads and various cooked dishes including a
reportedly, delicious apple-like pie. Likewise, despite the fruit's spiny
exterior, numerous seeds and short season, the profitability of cactus pear
fruit equals or exceeds that of common orchard crops, such as apples,
peaches and oranges.
The opuntia's high water-use efficiency also renders it ideal animal feed
for semi-arid regions where animal food is scarce. In fact, Mexico, Brazil,
the United States (mainly Texas), Peru, South Africa, and Tunisia already
produce significant amounts of animal feed from opuntia.
The opuntia also has medicinal applications. Following the tip from Sicilian
old-timers regarding its role in treating prostate inflammation, Dr. Nerd,
Mizrahi's colleague, contacted medicinal plant expert, the late Prof. Dan
Palevitch of the Agricultural Research Organization. Palevitch and Dr.
Alexander Levine, a urologist from the Soroka Medical Centre, found positive
results following treatment, with patients scheduled to undergo surgery
showing marked reduction in prostate size. Today, Prostacal, clinically
proven to alleviate the symptoms of benign prostatic hyperplasia, is
marketed worldwide by Herbamed Pharmaceuticals.
Can new cacti compete with successful existing agricultural crops? According
to Mizrahi, they have great commercial potential. In semi-arid regions,
opuntias can serve as fruits, vegetables, animal feed and as a
drought-tolerant perennial for reforestation, which can also provide
firewood. Furthermore, although the productivity of certain cacti is not
high, others can surpass that of important crops including mango, avocado,
banana, potato and tomatoes. While some export companies are wary of new
products, various markets continuously seek refreshing items, and are often
willing to pay prime prices for them. European enthusiasm for kiwi fruit
from New Zealand and avocado from Israel are classic examples. However, when
pressed for estimated market potentials, Mizrahi declines: "It would be
misleading," he says. "The fruits have never been sold before. However, they
look and taste far better than avocado - a virtually unknown crop until 35
years ago. Yet in its peak Israel sold 200 million dollars worth of avocados
annually."
Profits are trickling in as awareness of these previously unknown fruits
grows. Whoever experiences the fruits' exotic beauty and excitingly new
flavors and scents is bound to be excited by their market potential. Yet
continued advances require more research and funding. Meanwhile, Mizrahi's
experimental greenhouse at B.G.U.'s Institute of Applied Research, set
against the awkward scenery of desert high-rise buildings, transports its
visitors to a tapestry of distant lands, cultures and sensations.
Cooperation between Israel and Seed Source Countries
Mizrahi and colleagues are interested in expanding cooperative research
projects between Israel and seed source countries, backed by funding from
governmental and international organizations aimed at assisting developing
countries and expanding world food resources. Mizrahi's research has been
partially funded by GIARA (German-Israel Agricultural Research Agreement for
the Benefit of the Third World), IPALAC (the International Program for Arid
Land Agricultural Crops), and USAID. Recent research projects include:
Kenya: Joint research project with Egerton University, focussing on the
development of arid zone agriculture.
Botswana: Joint research station, partially funded by the NGO Thusano
Lefatseng, designed to develop improved horticultural techniques for
large-scale cultivation of the marula and other local exotic fruits, with
the aim of boosting food production for rural areas in Botswana.
Morocco: Joint project with Agadir University research team, headed by Prof.
Fausia Ibno Ameur, aimed at studying the Argan nut tree for commercial
domestication.
Mexico: Joint project with Dr. Peter Felker and Dr. Xingong Wang of Texas
A&M University, designed to examine cultivation possibilities of cactus pear
fruit clones in northern Mexico. The objective was to combine cold
hardiness, low seediness, high yields and high sugar concentrations. The
researchers also organized a conference for the Professional Association for
Cactus Development in which delegates from Argentina, Chile, Peru and Mexico
were present. A major theme of the conference was the relations between food
quality, medical benefits of soluble fiber, effects of cactus on diabetes,
and characterization of the mucilage in cactus for commercial gum
utilization (like guar and xanthan gums).
West Africa: Plant seedlings cultivated by Mizrahi, demonstrating
significantly enhanced yields, have been made available for experimental
testing in Africa (workshops in Bamako, Mali, 1997, and Zimbabwe, 1998).
Israeli Agriculture - Facts
* Size: Israel is only 470km long and 135km wide (at its widest).
* Geography and Diversity: Despite its compact borders, situated at the
junction of three continents, Israel boasts considerable geographic,
climatic and genetic diversity.
* Climate: Dry. Rainfall varies considerably, from 25 mm per year in the
Negev - Israel's southern desert, to 720 mm in the North.
* Irrigation: Israel uses three quarters of its water resources for
agriculture. It has an increasingly acute water shortage, exacerbated by its
growing population (nearly 6 million).
* Arable land: Only about 17% of Israel's land is arable (compared for
example, to 32% in France). Another 40% is pasturage, while permanent crops
account for only 5%.
* Agriculture: Although Israel started with a largely agricultural economy,
far-sighted R&D investments beginning in the 1960s promoted the rapid
expansion of high-tech industries. Today, agricultural exports account for a
mere 3.9% of Israel's total export market, compared to 30.3% during the
1960s - the heyday of the famous Jaffa orange. However, Israel benefits
greatly from its proximity to Europe and its warm climate. Israeli
agricultural exports comprise about 40% of Europe's off-season fruit and
vegetable market and are second only to Holland in European flower sales.
* Challenges: Israeli agriculture faces increasing challenges: limited water
resources, competition due to the implementation of international trade
agreements and, most importantly, expanding urbanization. Today 10% of
Israel (excluding the Negev Desert) is already built-up. Given Israel's high
population growth rate and other trends, forecasts predict that this could
rise to a staggering 50% by the year 2020, making Israel one of the most
densely populated countries in the world.