Date Morton, J. 1987. Date. p. 511. In: Fruits of warm climates. Julia F. Morton, Miami, FL. Date Other Uses Most of the dozen or more species of the genus Phoenix (family Palmae) are grown as ornamental palms indoors or out. Only the common date, P. dactylifera L., is cultivated for its fruit. Often called the edible date, it has few alternate names except in regional dialects. To the French, it is dattier; in German, it is dattel; in Italian, datteri; or dattero; in Spanish, datil; and, in Dutch, dadel. The Portuguese word is tamara. Description The date is an erect palm to 100 or 120 ft (30.5-36.5 m), the trunk clothed from the ground up with upward-pointing, overlapping, persistent, woody leaf bases. After the first 6 to 16 years, numerous suckers will arise around its base.

The feather-like leaves, up to 20 ft (6 m) long, are composed of a spiny petiole, a stout midrib, and slender, gray-green or bluish-green pinnae 8 to 16 in (20-40 cm) long, and folded in half lengthwise. Each leaf emerges from a sheath that splits into a network of fibers remaining at the leaf base. Small fragrant flowers (the female whitish, the male waxy and cream colored), are borne on a branched spadix divided into 25 to 150 strands 12 to 30 in (30-75 cm) long on female plants, only 6 to 9 in (15-22.5 cm) long on male plants. One large inflorescence may embrace 6,000 to 10,000 flowers. Some date palms have strands bearing both male and female flowers; others may have perfect flowers. As the fruits develop, the stalk holding the cluster may elongate 6 ft (1.8 m) while it bends over because of the weight.

The fruit is oblong, 1 to 3 in (2.5-7.5 cm) long, dark-brown, reddish, or yellowish-brown when ripe with thin or thickish skin, thick, sweet flesh (astringent until fully ripe) and a single, cylindrical, slender, very hard stone grooved down one side. Origin and Distribution The date palm is believed to have originated in the lands around the Persian Gulf and in ancient times was especially abundant between the Nile and Euphrates rivers. Alphonse de Candolle claimed that it ranged in prehistoric times from Senegal to the basin of the Indus River in northern India, especially between latitudes 15 and 30. There is archeological evidence of cultivation in eastern Arabia in 4,000 B.C. It was much revered and regarded as a symbol of fertility, and depicted in bas relief and on coins. Literature devoted to its history and romance is voluminous. Nomads planted the date at oases in the deserts and Arabs introduced it into Spain. It has long been grown on the French Riviera, in southern Italy, Sicily and Greece, though the fruit does not reach perfection in these areas.

Possibly it fares better in the Cape Verde Islands, for a program of date improvement was launched there in the late 1950's. Iraq has always led the world in date production. Presently, there are 22 million date palms in that country producing nearly 600,000 tons of dates annually. The Basra area is renowned for its cultivars of outstanding quality. The date has been traditionally a staple food in Algeria, Morocco, Tunisia, Egypt, the Sudan, Arabia and Iran. Blatter quotes the writer, Vogel, as stating: "When Abdel-Gelil besieged Suckna in 1824, he cut down no fewer than 43,000 trees, to compel the town to surrender; nevertheless, there are still at least 70,000 left." In 1980, production in Saudi Arabia was brought to nearly a half-million tons from 11 million palms because of government subsidies, improved technology, and a royal decree that dates be included in meals in govern ment and civic institutions and that hygienically-packed dates be regularly available in the markets.

Farmers receive financial rewards for each offshoot of a high-quality date planted at a prescribed spacing. The Ministry of Agriculture has established training courses throughout the country to teach modern agricultural methods, including mechanization of all possible operations in date culture, and recognition and special roles of the many local cultivars. In West Africa, near the Sahara, only dry, sugary types can be grown. Bonavia introduced seeds of 26 kinds of dates from the Near East into northern India and Pakistan in 1869; and, in 1909, D. Milne, the Economic Botanist for the Punjab, introduced offshoots and established the date as a cultivated crop in Pakistan. The fruits ripen well in northwestern India and at the Fruit Research Center in Saharanpur. In southern India, the climate is unfavorable for date production. A few trees around Bohol in the Philippines are said to bear an abundance of fruits of good quality. The date palm has been introduced into Australia, and into northeastern Argentina and Brazil where it may prosper in dry zones. Some dates are supplying fruits for the market on the small island of Margarita off the coast from northern Venezuela.

Seed-propagated dates are found in many tropical and sub-tropical regions where they are valued as ornamentals but where the climate is unsuitable for fruit production. In November 1899, 75 plants were sent from Algiers to Jamaica. They were kept in a nursery until February 1901 and then 69 were planted at Hope Gardens. The female palms ultimately bore large bunches of fruits but they were ready to mature in October during the rainy season and, accordingly, the fruits rotted and fell. Only occasionally have date palms borne normal fruits in the Bahamas and South Florida. Spanish explorers introduced the date into Mexico, around Sonora and Sinaloa, and Baja California. The palms were only seedlings. Still, the fruits had great appeal and were being exported from Baja California in 1837. The first date palms in California were seedlings planted by Franciscan and Jesuit missionaries in 1769. Potted offshoots from Egypt reached California in 1890 and numerous other introductions have been made into that state and into the drier parts of southern Arizona around Tempe and Phoenix.

In 1912, Paul and Wilson Popenoe purchased a total of 16,000 offshoots of selected cultivars in Algeria, eastern Arabia and Iraq and transported them to California for distribution by their father, F.O. Popenoe who was a leader in encouraging date culture in California. It became a profitable crop, especially in the Coachella Valley. There are now about a quarter of a million bearing trees in California and Arizona. Varieties It would be impractical to deal in depth with date cultivars here. Paul Popenoe listed 1,500 and provided descriptions of the fruit and palm, as well as the history and significance, of the most important, country by country, in 90 pages of his book, The Date Palm, written in 1924 but published in 1973 and readily available.

In Iraq, there are presently 450 female cultivars, the most important of which are: 'Zahdi' (43% of the crop; low in price); 'Sayer' 23% of the crop and high-priced); 'Halawi' (13% of the crop and high-priced); 'Khadrawi (6% of the crop and high-priced); also 'Khastawi, 'Brem', and 'Chipchap'. Sawaya and colleagues (1983) have reported on the sugars, tannins and vitamins in 55 major date cultivars of Saudi Arabia. The following, with brief comments, are the dates most commonly grown: 'Barhi' introduced into California in 1913 from Basra, Iraq; nearly cylindrical, light amber to dark brown when ripe; soft, with thick flesh and rich flavor; of superb quality. For shipment needs refrigeration as soon as picked, then curing and special packing. 'Dayri' (the "Monastery Date")introduced into California from convent grounds in Dayri, Iraq, in 1913; long, slender, nearly black, soft. Palm requires special care.

Not grown extensively in California. Fig. 1: An 8-year old-'Deglet Noor' date palm in a private garden near Indio, California Photo'd by Avery Edwin Field, Oct. 1924. In: W.T. Swingle, Date Growing: a new industry for Southwest States U.S. Dept. of Agriculture Yearbook 1926. 'Deglet Noor' 'Halawi' 'Zahdi' Fig. 2: 'Deglet Noor', (top) a semi soft date. 'Halawi', (center) a leading export date of Iraq. 'Zahdi', (bottom) a small date from northern Iraq. In: D.W. Albert and R H. Hilgeman, Date growing in Arizona. Bull. 149, U. Arizona, Agr. Exper. Sta., Tucson, Ariz. May 1935. 'Deglet Noor'a leading date in Algeria and Tunisia; and in the latter country it is grown in inland oases and is the chief export cultivar. It was introduced into California in 1900 and now constitutes 75% of the California crop.

It is semi-dry, not very sweet; keeps well; is hydrated before shipping. Much used for cooking. The palm is high yielding but not very tolerant of rain and atmospheric humidity. 'Halawy' ('Halawi')introduced into California from Iraq; soft, extremely sweet, small to medium; may shrivel during ripening unless the palm is well-watered. It is especially tolerant of humidity. 'Hayany' ('Hayani')the cultivar most extensively planted in Egypt; but not exported. Introduced into California in 1901, and is sold fresh; is not easy to cure. The fruit is dark-red to nearly black; soft. The palm is one of the most cold-tolerant. 'Khadrawy' ('Khadrawi')important in Iraq and Saudi Arabia, and is grown to some extent in California and Arizona. It is the cultivar most favored by Arabs but too dark in color to be popular on the American market, though it is a soft date of the highest quality. It is early-ripening; does not keep too well. This cultivar is the smallest edible date palm grown in the United States and it is fairly tolerant of rain and humidity.

'Khastawi' ('Khustawi'; 'Kustawy')the leading soft date in Iraq; sirupy, small in size; prized for dessert; keeps well. The palm is large and vigorous and produces its offshoots high on the trunk in California. The fruit is resistant to humidity. 'Maktoom'introduced into California from Iraq in 1902; large, red-brown; thick-skinned, soft, mealy, medium sweet; resistant to humidity. 'Medjool'formerly exported from Morocco; 11 off-shoots imported into California from Bou Denib oases in French Morocco in 1927; is now marketed as a deluxe date in California; is large, soft, and luscious but ships well. 'Saidy' ('Saidi')highly prized in Libya; soft, very sweet; palm is a heavy bearer; needs a very hot climate.

'Sayer' ('Sayir')the most widely grown cultivar in the Old World and much exported to Europe and the Orient; dark orange-brown, of medium size, soft, sirupy, and sometimes some of the sirup is drained out and sold separately; not of high quality but the palm is one of the most tolerant of salt and other adverse factors. 'Thoory'('Thuri')popular in Algeria; does well in California. Fruit is dry; when cured is brown-red with bluish bloom with very wrinkled skin and the flesh is sometimes hard and brittle but the flavor is good, sweet and nutty. Keeps well; often carried on journeys. The palm is stout with short, stiff leaves; bears heavily, and clusters are very large; somewhat tolerant of humidity. 'Zahdi'('Zahidi')the oldest-known cultivar, consumed in great quantity in the Middle East; introduced into California about 1900. Of medium size, cylindrical, light golden-brown; semi-dry but harvested and sold in 3 stages: soft, medium-hard, and hard: very sugary; keeps well for months; much used for culinary purposes.

The palm is stout, fast growing, heavy bearing; drought resistant; has little tolerance of high humidity. Among the less well-known cultivars in California are: 'Amir Hajj'introduced from Mandali Oasis in Iraq in 1929. The fruit is soft, with thin skin and thick flesh; of superior quality but little grown in the United States. 'Iteema'offshoots from Algeria were introduced into California in 1900. The fruit is large, oblong, light amber, soft, very sweet. Much grown in Algeria but not rain resistant and little grown in California. 'Migraf' ('Mejraf)a very popular cultivar in Southern Yemen. Fruit is light golden-amber, large; of good quality. In inland oases of Tunisia, in addition to the 'Deglet Noor', there is 'Ftimi' ('Alligue') which is equally subject to humidity, less productive and less disease-resistant. 'Manakbir' has a large fruit and ripens earlier but has the disadvantage that the palm produces few offshoots and its multiplication is limited.

In coastal oases, the main cultivars are 'Kenta', Agnioua', 'Bouhatam' and 'Lemsi' which come into season early and ripen before the fall rains. They require less heat than other cultivars. The fruits are more or less dry and the flesh firm. In all date-growing areas, some confusion is caused if a seed from harvested fruits falls at the base of a select cultivar and the seedling springs up unnoticed among the offshoots. Such seedlings should be watched for and discarded lest they be mistakenly transplanted with the offshoots and later bear fruits of inferior quality. Pollination Date pollen is abundant but is not airborne very far. It has become customary to plant one male palm for every 48 or 50 females to provide pollen for artificial pollination which is an ancient practice. In Saudi Arabia and a few other areas of the Old World and in California and Arizona, the long spines on the petioles are first removed to facilitate the pollinating operation.

Traditionally, a few strands of open male flowers are put upside-down in a female inflorescence while it is still upright, and a cord is bound around the latter to keep the strands in place when the cluster enlarges and bends downward. However, the pollen can be dried and will keep for 6 months at room temperature. Pollen stored for one year at 8°F (-13.33°C) has given 58%fruit set. Some has been found viable after 7 years of storage, and it is reported that pollen has been kept 14 years in Iran. There are various techniques for applying stored pollen to the female flowers. It may be dusted on by a tractor-drawn, convertible pollen/pesticide machine, or applied with a cotton pad, or sprayed on with a long tubed applicator or other device. Lack of pollination results in small, seedless fruits. In acute shortages, pollen of another species of Phoenix or of some other genera may be used. Climate The date palm must have full sun. It cannot live in the shade. It will grow in all warm climates where the temper ature rarely falls to 20°F (-6.67°C).

When the palm is dormant, it can stand temperatures that low, but when in flower or fruit the mean temperature must be above 64°F (17.78°C). Commercial fruit production is possible only where there is a long, hot growing season with daily maximum temperatures of 90°F (32.22°C) and virtually no rainless than 1/2 in (1.25 cm) in the ripening season. The date can tolerate long periods of drought though, for heavy bearing, it has a high water requirement. This is best supplied by periodic flooding from the rivers in North Africa and by subsurface water rather than by rain. (See remarks on irrigation under "Culture"). Soil The date thrives in sand, sandy loam, clay and other heavy soils. It needs good drainage and aeration. It is remarkably tolerant of alkali. A moderate degree of salinity is not harmful but excessive salt will stunt growth and lower the quality of the fruit. Propagation Date palms grow readily from seeds if the seeds and seedlings are kept constantly wet. But seedlings are variable and take 6 to 10 years to fruit.

Furthermore, 50% of the seedlings may turn out to be males. The best and common means of propagation is by transplanting the suckers, or offshoots when they are 3 to 5 years old and weigh 40 to 75 lbs (18-34 kg). They are usually separated from the parent palm as needed, but in southern Algeria suckers are often put on sale standing in tubs of water. Some offshoots are maintained in nurseries until roots are formed, though most are set directly in the field after a seasoning period of 10 to 15 days just lying on the ground, in order to lose 12 to 15% of their moisture. In parts of Egypt subject to annual flooding, very large offshootsup to 500lbs (226 kg) are planted to avoid water damage. In general, it is said that at least 2 offshoots can be taken from each palm annually for a period of 10 to 15 years. The potential of tissue culture for multiplication of date palms is being explored in Iraq, Saudi Arabia and in California.

Culture In Tunisia, in former times, it was customary to plant 200 date palms per acre (500/ha). Today, optimum density is considered to be 50 per acre (120/ha) and this is about the standard in the Coachella Valley of California, but small-growing palms may be set much closer. The off shoots, trimmed back 1/3 or 1/4, leaving some of the stiff outer leaves to protect the inner ones, are usually planted 30 to 33 ft (9-10 m) apart each way. The holes should be 3 ft (0.9 m) wide and deep, prepared and enriched several months in advance, and may be encircled by a watering ditch. If the soil dries out prior to planting, the holes are filled with water at that time. In Algeria and Oman, the palms may be set much deeper in order to be closer to ground water, but this may result in drowning the palms when irrigating or they may be smothered by sandstorms. Planting may be done at any time of year, but most often takes place in spring or fall. In Tunisia planting is done in April and May.

The base is set vertically in the ground and the curving fronds will gradually assume an upright position, especially if the concave side is set to face south. Most plants will root in 2 months if the soil is kept constantly moist, while some may be delayed for a year or even several years before they show vigorous growth. Some growers expect a loss of 25% of the off shoots. Formerly, the young plants in nursery rows were wrapped nearly to the top with old leaves, paper or burlap sacks for the first year to prevent dehydration by cold, heat or wind. But it is now held that such wrapping interferes with the proper development of the leaves. The offshoots that survive may begin to bloom in 3 years and fruit a year later but a substantial crop is not possible before the 5th or 6th year. In 8 or 10 years, the date will attain full production and it will keep on for a century though productivity declines after 60 to 80 years and also the flowers will be too high to pollinate and the fruits too high to pick.

The palm grows at the rate of 1 to 11/2 ft (30-45 cm) a year and can reach 20 ft in 15 to 20 years depending on the cultivar and soil and water conditions. In Iraq, date palms are fertilized once a year with manure at the rate of 44 lbs (20 kg) per tree. Commercial fertilizers are utilized in Saudi Arabia and the United States. Of more importance is the supply of water, a large amount being necessary and it is usually supplied by irrigation ditches. In some Old World plantations rising tides cause rivers to flood the ditches twice a day. Where this natural irrigation does not occur, the palms are watered 15 to 40 times a year. Overhead moisture (including rain) during fruit development will cause minute cracks (checking), beginning at the apex of the fruit which ultimately darkens. In California, the fruit clusters are covered with paper bags to shelter them from rain, dust, and predators.

The female inflorescences may be shortened, thinned out, or some removed entirely at pollinating time, or several weeks later when the stalk has drooped lower, in order to conserve the palm's energy for the following season. Some growers advise leaving no more than 12 bunches per palm. Many leave only 30 strands per cluster, each with about 30 fruits. Without thinning, fruits would be borne only every other year. During the pollinating operation, a grower may tie the elongating flower stalk to a palm frond to prevent breaking when later laden with fruit. The palms are pruned twice a year, dry fronds being removed in the fall and the leaf bases may be taken off in the spring in order that their fiber may be used as a substitute for coir In Iraq, growth regulators have been experimentally applied to developing dates. In 'Zahdi' and 'Sayer', naphthaleneacetic acid, at 60 ppm, applied 15 to 16 weeks after pollination, improved quality and increased fruit weight by 39%. Moisture content was elevated. Ripening was delayed for 30 days or more.

In the Old World, most date plantations are intercropped with vegetables, cereals or fodder crops in the first few years and subsequently with low growing fruit trees or grapevines. Some authorities hold that this practice distracts the grower from proper care of the dates. In mechanized plantations, intercropping is not possible inasmuch as space must be left for the mobile equipment. Yield Ordinarily, in palms 5 to 8 years old, the first crop will be 17.5 to 22 lbs (8-10 kg) per palm; at 13 years, 132 to 176 lbs (60-80 kg). Some improved cultivars, at high densities, have yielded over 220 lbs (100 kg) per year. 'Deglet Noor' in California may yield 4.5 to 7 tons per acre (11-17 tons/ha). Harvesting and Ripening Some high-quality dates are picked individually by hand, but most are harvested by cutting off the entire cluster.

In North Africa, the harvesters climb the palms, use forked sticks or ropes to lower the fruit clusters, or they may pass the clusters carefully down from hand to hand. Growers in California and Saudi Arabia use various mechanized means to expedite harvestingsaddles, extension ladders, or mobile steel towers with catwalks for pickers. All fruits in a cluster and all clusters on a palm do not ripen at the same time. A number of pickings may have to be made over a period of several weeks. In the Coachella Valley, dates ripen from late September through December and there are 6 to 8 pickings per palm.

Dates go through 4 stages of development: 1) Chimri, or Kimri, stage, the first 17 weeks after pollination: green, hard, bitter, 80% moisture, 50% sugars (glucose and fructose) by dry weight; 2) Khalal stage, the next 6 weeks: become full grown, still hard; color changes to yellow, orange or red, sugars increase, become largely sucrose; 3 ) Rutab stage, the next 4 weeks: half-ripe; soften, turn light brown; some sucrose reverts to reducing sugar which gains prominence; 4) Tamar stage: ripe; the last 2 weeks; in soft dates, the sugar becomes mostly reducing sugar; semi-dry and dry dates will have nearly 50% each of sucrose and reducing sugars. Soft dates may be picked early while they are still light colored. Semi dry dates may be picked as soon as they are soft and then ripened artificially at temperatures of 80° to 95°F (26.67°-35°C), depending on the cultivar. Dry dates may be left on the palm until they are fully ripe.

Dry dates that have become too dehydrated and hardened on the palm are rehydrated by soaking in cold, tepid or hot water, or by exposure to steam or a humid atmosphere. Extremely dry weather will cause dates to shrivel on the palm. In the Sudan, the fruits are picked when just mature and then are ripened in jars to prevent so much loss of moisture. Rain, high humidity or cool temperatures during the maturing period may cause fruit drop or checking, splitting of the skin, darkening, blacknose, imperfect maturation, and excessive moisture content, or even rotting. Under such adverse weather conditions, as may occur in the Salt River Valley, Arizona, dates must be harvested while still immature and ripened artificially. In the Old World, there are many different methods of doing this: storing in earthen jars, placing the jars in sun hot enough to prevent spoilage, boiling the fruits in water and then sun drying. In Australia, entire clusters are kept under cover with the cut end of the stalk in water until the fruits are fully ripe. In modern packing houses, prematurely harvested dates are ripened in controlled atmospheres, the degrees of temperature and humidity varying with the nature of the cultivar.

Where there is low atmospheric humidity outdoors and adequate sunshine, harvested dates are sun dried whole or cut in half. For fresh shipment in California, the normally ripe, harvested fruits are carried to packing plants, weighed, inspected by agents of the United States Department of Agriculture, fumigated, cleaned, graded, packed, stored under refrigeration, and released to markets according to demand. Saudi Arabia has constructed a number of extra-modern processing plants for fumigation, washing, drying, and packing of dates prior to cold storage. Keeping Quality Slightly underripe 'Deglet Noor' dates will keep at 32°F (0°C) up to 10 months; fully mature, for 5 to 6 months. Freezing will extend the storage life for a much longer period. In India, sun-dried dates, buried in sand, have kept well for 1 1/2 years and then have been devoured by worms. Pests and Diseases Unripe fruits are attacked by Coccotrypes daclyliperda which makes them fall prematurely. Ripe fruits are often infested by nitidulidsCarpophilus hemipterus, C. multilatus (C.

dimidiatus), Urophorus humeralis, and Heptoncus luteolus, which cause decay. Control by insecticides is necessary to avoid serious losses. In Israel, the fruit clusters are covered with netting to protect them from such pests as Vespa orientalis, Cadra figulilella and Arenipes sabella as well as from depredations by lizards and birds. In Pakistan, the red weevil, or Indian palm weevil, Rhynchophorus ferrugineus, bores into the leaf bases at the top of the trunk, causing the entire crown to wither and die. The rhinocereus beetle, or black palm beetle, Oryctes rhinocerus, occasionally attacks the date. Its feeding damage may provide entrance-ways for the weevil. Scale insects may infest the leaves and the trunk. They have been controlled by trimming off the heavily infested leaves, spraying the remaining ones, and treating the fire resistant trunk with a blowtorch. Two of the most destructive scales are the Marlatt scale, Phoenicoccus marlatti; which attacks the thick leaf bases, and the Parlatoria scale, Parlatoria blanchardii, which is active in summer.

The latter was the object of an eradication campaign in California and Arizona in the late 1930's. The date mite scars the fruits while they are still green. A tineid moth and a beetle, Lasioderma testacea, have damaged stored dates in the Punjab. Dates held in storage are subject to invasion by the fig-moth, Ephestia cautella, and the Indian meal-moth, Plodia interpunctella. Fusarium albedinis causes the disastrous Bayoud, or Baioudh, disease in Morocco and Algeria. It is evidenced by a progressive fading and wilting of the leaves. Over a 9-year study period of 26 resistant varieties in Morocco, Bayoud disease reduced the planting density from 364 palms per acre (900/ha) to 121 to 142 per acre (300-350/ha). It is because of this disease that 'Medjool' can no longer be grown commercially in Morocco and Algeria. Decay of the inflorescence is caused by Manginiella scaeltae in humid seasons.

Several brown stains will be seen on the unopened spathe and the pedicels of the opened cluster will be coated with white "down". Palm leaf pustule, small, dark-brown or black cylindrical eruptions exoding yellow spores, resulting from infestation by the fungus Graphiola phoenicis, is widespread but often a serious problem in Egypt. Date palm decline may be physiological or the result of a species of the fungus genus Omphalia. Diplodia disease is a fungus manifestation on leafstalks and offshoots and it may kill the latter if not controlled. The fungus caused condition called "black scorch" stunts, distorts and blackens leaves and adjacent inflorescences. Other fungus diseases include pinhead spot (Diderma effusum), gray blight (Pestalotia palmarum) and spongy white rot (Polyporus adustus). The date, as well as its relative, Phoenix canariensis Hort. ex Chaub., has shown susceptibility to lethal yellowing in Florida and Texas. No commercial plantings have been affected.

Food Uses Dry or soft dates are eaten out-of-hand, or may be seeded and stuffed, or chopped and used in a great variety of ways: on cereal, in pudding, bread, cakes, cookies, ice cream, or candy bars. The pitting may be done in factories either by crushing and sieving the fruits or, with more sophistication, by piercing the seed out, leaving the fruit whole. The calyces may be mechanically removed also. Surplus dates are made into cubes, paste, spread, powder (date sugar), jam, jelly, juice, sirup, vinegar or alcohol. Decolored and filtered date juice yields a clear invert sugar solution. Libya is the leading producer of date sirup and alcohol. Cull fruits are dehydrated, ground and mixed with grain to form a very nutritious stockfeed. Dried dates are fed to camels, horses and dogs in the Sahara desert. In northern Nigeria, dates and peppers added to the native beer are believed to make it less intoxicating.

The First International Date Conference was held in Tripoli, Libya in 1959, and led to the development of a special program under the Food and Agriculture Organization of the United Nations to promote the commercial utilizetion of substandard or physically defective dates. Young leaves are cooked and eaten as a vegetable, as is the terminal bud or heart, though its removal kills the palm. In India, date seeds are roasted, ground, and used to adulterate coffee. The finely ground seeds are mixed with flour to make bread in times of scarcity. In North Africa, Ghana and the Ivory Coast, date palms are tapped for the sweet sap which is converted into palm sugar, molasses or alcoholic beverages, but each palm should not be tapped more than 2 or 3 times. Tapping the edible date palm interferes with fruit production and it is wiser to tap P. sylvestris, which is not valued for its fruit, or some other of the 20 well-known palm species exploited for sugar. When the terminal bud is cut out for eating, the cavity fills with a thick, sweet fluid (called lagbi in India) that is drunk for refreshment but is slightly purgative.

It ferments in a few hours and is highly intoxicating. Fresh spathes, by distillation, yield an aromatic fluid enjoyed by the Arabian people. Other Uses Seeds: Date seeds have been soaked in water until soft and then fed to horses, cattle, camels, sheep and goats. Dried and ground up, they are now included in chicken feed. They contain 7.17-9% moisture, 1.82-5.2% protein. 6.8-9.32% fat, 65.5% carbohydrates, 6.4-13 6% fiber, 0.89-1.57% ash, also sterols and estrone, and an alkali-soluble polysaccharide. The seeds contain 6 to 8% of a yellow-green, non-drying oil suitable for use in soap and cosmetic products. The fatty acids of the oil are: lauric, 8%; myristic, 4%; palmitic, 25%; stearic, 10%, oleic, 45%, linoleic, 10%; plus some caprylic and capric acid.

Date seeds may also be processed chemically as a source of oxalic acid, the yield amounting to 65%. In addition, the seeds are burned to make charcoal for silversmiths, and they are often strung in necklaces. Leaves: In Italy, there are some groves of date palms maintained solely to supply the young leaves for religious use on Palm Sunday. In Spain, only the leaves of male palms are utilized for this purpose. In North Africa, the leaves have been commonly used for making huts. Mature leaves are made into mats, screens, baskets, crates and fans. The processed leaflets, combined with ground up peanut shells and corn cobs, are used for making insulating board. The leaf petioles have been found to be a good source of cellulose pulp. Dried, they are used as walking sticks, brooms, fishing floats, and fuel. The midribs are made into baskets. The leaf sheaths have been prized for their scent. Fiber from the old leaf sheaths is used for various purposes including packsaddles, rope, coarse cloth and large hats. It has been tested as material for filtering drainage pipes in Iraq, as a substitute for imported filters.

Analyses of the leaves show: 0.4-0.66% nitrogen; 0.025 0.062% phosphorus; 0.33-0.66% potassium; 10-16.4% ash. There is some coumarin in the leaves and leaf sheaths. Fruit clusters: The stripped fruit clusters are used as brooms. The fruit stalks contain 0.28-0.42% nitrogen, 0.017-0.04% phosphorus; 3.46-4.94% potassium; 7.7-9.88% ash. Fruits: In Pakistan, a viscous, thick sirup made from the ripe fruits, is employed as a coating for leather bags and pipes to prevent leaking. Wood: Posts and rafters for huts are fashioned of the wood from the trunk of the date palm, though this wood is lighter than that of the coconut. It is soft in the center and not very durable. That of male trees and old, un productive females is readily available and used for aqueducts, bridges and various kinds of construction, also parts of dhows.

All left over parts of the trunk are burned for fuel. Medicinal Uses: The fruit, because of its tannin content, is used medicinally as a detersive and astringent in intestinal troubles. In the form of an infusion, decoction, sirup or paste, is administered as a treatment for sore throat, colds, bronchial catarrh. It is taken to relieve fever, cystisis, gonorrhea, edema, liver and abdominal troubles. And it is said to counteract alcohol intoxication. The seed powder is an ingredient in a paste given to relieve ague. A gum that exudes from the wounded trunk is employed in India for treating diarrhea and genito-urinary ailments. It is diuretic and demulcent. The roots are used against toothache. The pollen yields an estrogenic principle, estrone, and has a gonadotropic effect on young rats. Food Value Per 100 g of Edible Portion* Fresh, uncooked CHAPTER IV: CLIMATIC REQUIREMENTS OF DATE PALM CHAPTER IV: CLIMATIC REQUIREMENTS OF DATE PALM By A. Zaid and P.F.

de Wet Date Production Support Programme The climatic factors influencing date growth and production are discussed in this chapter. Temperature, rain, humidity, light and wind are the most important climatic factors which determine the suitability of a specific site for growing date palm. 1. Temperature requirements The highest maximum temperatures found in the date growing areas of the world are the result of low humidity, great insolation and long days in summer. There are several ways to record temperature, and the analysis of its effect will be conducted accordingly. First, there is the average daily temperature with a daily maximum and a daily minimum (Table 19), then the values of average annual temperatures are also used (Table 20). The average of a larger number of daily records translated into monthly values will, however, give a more accurate result (Table 21). TABLE 19 Average maximum and minimum daily temperatures of various date growing areas (°C) Station/Country 20.7 Source: Dowson, 1982. To compare the climates of different places with regard to their suitability for date cultivation, it is appropriate to use the average of the two extremes.

However, in order to differentiate between places which may grow dates and those that are not suitable, it is recommended that use be made of the annual average of the daily averages. Date palm is cultivated in arid and semi-arid regions which are characterised by long and hot summers, no (or at most low) rainfall, and very low relative humidity level during the ripening period. Exceptional high temperatures (± 56°C) are well endured by a date palm for several days under irrigation. During winters, temperatures below 0°C are also endured. The zero vegetation point of a date palm is 7°C, above this level growth is active and reaches its optimum at about 32°C; the growth will continue at a stable rate until the temperature reaches 38°C/40°C when it will start decreasing. Even though date palm is a thermopile species, it withstands large temperature fluctuations. Below 7°C growth stops and this stage is called a resting period. When the temperature decreases for a certain period to below 0°C, it causes metabolic disorders which lead to partial or total damage of leaves.

At -6°C pinnae margins turn yellow and dry out (Figures 29a and 29b). Inflorescences are also heavily damaged by frost (Figure 30). When frost periods are suspected, inflorescences should be protected with craft paper bags immediately after pollination (Figure 31). From -9 to -15°C, leaves of medium and outside canopy will be damaged and dry out. If these low temperatures are maintained for a long period (12 hours to 5 days) all leaves will show frost damage and the palm will look as if it was burnt (cases of Morocco date plantations in 1952, and 1965; Iran, 1964; USA, 1913, 1937, 1949 and 1959 (Mason, 1925a; Nixon, 1937). The more leaves damaged, the greater the possibilities of poor fruit quality that year.

Poor flowering could also be expected the TABLE 21 Average daily and annual maximum air temperatures at various date plantations in northern and southern hemispheres Station/Country 22.7 29.7 It is worth mentioning that owing to the fibrillium, the meristematic area of a date palm (growth centre) is well protected against frost. After frost occurrence and during early spring, the damaged palm restarts its normal growth. Nixon (1937) noted that date gardens that were irrigated during frost periods were less damaged than the ones that were not irrigated. The Zahidi variety (Iraq) was found to be the least damaged by frost while Khalas (also Iraq) is the most sensitive. According to Mason (1925), the growth of a date palm does not cease if: (i) minimum daily temperature does not fall below freezing point, and (ii) maximum daily temperature at the growth centre does not fall below 9 to 10°C. The temperature requirements presented below are those of normal growth, flowering and fruit maturation. Date palm flowering is initiated after a cold period, when the temperature becomes high enough and reaches a level known as the flowering zero (0).

This temperature level varies according to varieties and to local climatic conditions. Table 22 indicates the flowering time of several date growing regions. TABLE 22 Flowering time and related average daily temperatures of various date plantations around the world Plantations/Country September - April Source: Djerbi, 1995; McColl, 1992. The above two criteria (flowering temperature and fruiting period) allow the calculation of the heat units, which correspond to the sum of the average daily temperatures from flowering time till fruit maturation, that are necessary for a given variety under a given environment. Different methods of calculating this heat unit value were used by the following authors: - In 1879, Cosson estimated the sum of heat units necessary for Algerian date varieties as 6,000 °C. Similar results were obtained by Fisher (1883) while working with Egyptian varieties (6,136°C). Those authors' techniques were based on using the earliest date in each place when the temperature first reached 18°C in the year, and the last date of the year when the temperature dropped below that value.

- De Candolle (1883) considered 10°C as the growth's zero value. By subtracting it from the average daily temperature and then adding all the obtained values together, he found that 5100°C was the required heat units to ripen fruits of some date varieties completely. - Swingle (1904) added the daily temperature maxima for a period of 184 days. The growth zero value used was 18°C (since the flowering process does not commence below 18°C) and consequently the value of heat units for several date plantations are shown in Table 24. - Munier (1973) used the same technique as Swingle but differentiated between varieties such as Gharas, Degla Beida with 180 days and a heat unit value of 1,800°C, and Deglet Nour with 200 days and a heat unit value of 1,890°C. His results, presented below (Table 25), concluded that the value of 1,000 °C is the minimum limit for growing a productive date palm.

TABLE 24 Value of heat units at various date growing areas in Algeria and Iraq Plantation/Country Largeau/Chad 1,860 In conclusion, the value of the heat unit is of great importance for defining the suitability of a site in which to grow a productive date palm, to eliminate areas that cannot grow date palm, and also to help in variety selection. Furthermore, the temperatures shown in the above table can be regarded as optimum for date cultivation. 2. Rain effect Date palm culture has mostly been developed in areas with winter rainfall which does not cause harm to the date fruits, but benefits the soils of the plantations by lessivating the deposited surface salt and avoiding the upward movement of salt from lower layers. Table 26 shows that the main date-growing regions are almost rainless until November. In these countries harvest begins mid August until the end of October. Rain during the flowering and harvest season is likely to cause some damage to the fruits. TABLE 26 Rainfall in the main date growing regions Grove/Country 3.1 Source: Nixon and Carpenter, 1978; Dowson, 1982; and McColl, 1992.

There is controversy about the effect of rain on pollination and fruit set. Rain that occurs just after pollination is considered as a washing agent that takes away most of the applied pollen. Another negative effect of rain on fruit set also results from low temperatures that accompany or follow rain. A third factor is the reduction of the flower's receptivity when in contact with water. Date growers must assume that the rain will affect pollination/fruit set, and any pollination operation immediately preceded or followed by rain (4 to 6 hours) must be repeated. Rain is also responsible for increasing the relative air humidity creating favourable conditions for cryptogamic diseases that result in the rotting of inflorescences. A light spring shower with ahigh relative humidity followed by warm temperature just before pollination causes the Khamedj disease (Mauginiella schaettae). This high relative humidity is also associated with the pollen's explosion (Further details on this subject are to be found in the Chapter "Pollination and Bunch Management"). The major damage caused by rain occurs when either the rain is early, or the dates are late in ripening.

In fact, rain does not seriously damage the dates when they are still at the early Khalal stage, but rather has a beneficial effect by washing away all dust and sand particles from the fruits. Rain can however cause severe checking and cracking in the Kimri and late Khalal stages. In some areas of California (USA), where rain damage is frequent, date growers commonly use craft paper to protect fruit bunches (Figure 32). Rutab and Tamar stages are the most sensitive since rain and associated humidity cause severe damage including rotting and fall-off of the fruit. Rain or cool weather occurring near harvesting is also inclined to delay ripening. It is worth mentioning that the amount of any particular rain is of less importance than the conditions under which it occurs (Nixon and Carpenter, 1978). A light shower accompanied by prolonged periods of cloudy weather and high relative humidity may cause more damage than heavy rain followed by clear weather and dry winds. Varieties of dates differ in their susceptibility to rain and humidity. Dayri, Khastawi, Thoory, Khadraoui, and Sair, under Coachella Valley conditions, were found to be the least damaged of sixteen varieties (Nixon, 1950).

Zahidi, Khalas and Barhee varieties had average damage, while Deglet Nour, Yatima, Hayani and Ghars were the most sensitive. Both very early (Al Mehtari/Iran) and late varieties (Khissab and Hilali/Iraq) escape the rain and consequently their fruits are not affected. The chances of damaging rain (in August, September and October for Northern Hemisphere and January, February and March for the Southern Hemisphere) in any given season is more important from a practical point of view. Hence, a season could be considered: Good to average, if less than 50 mm of rain fell in each of the three months; average to poor, if more than 50 mm of rain fell in one of the three months, poor, if more than 50 mm of rain fell in two of the three months; and very poor, if more than 50 mm of rain fell in each of the three months. The extension of date palm culture to the southern part of the Sahara Desert (Sahel) came as an exception to the above with heavy rain in July, August and September, and a dry period during October, November, and December (Table 27).

TABLE 27 Rain distribution and fructification periods in the Sahel date growing countries Source: Djerbi, 1995. Table 27 illustrates the case of Mali, Mauritania and Chad where there is a perturbance of the date production cycle resulting in two periods of fructification: i) One first short cycle, of about 130 to 150 days, characterised by flowering during the dry season and fruit maturation at early rainy season with an abundant yield but of a low quality. ii) A second long cycle, of about 180 to 200 days, where flowering occurs during the rainy period and the fruit maturation at the dry season; the yield is less abundant but of a high quality. Table 28 illustrates the above two cycles in both Mali and Niger. TABLE 28 Fructification cycles and rain distribution in two Sahel growing countries Source: Djerbi, 1995. 3. Air relative humidity Depending on air humidity at the locality of a date palm plantation, various advantages and/or disadvantages are found. In fact, the date palm eco-system is mostly of an arid nature where air relative humidity has a large influence.

In the presence of high air humidity, some leaf diseases, such as Graphiola leaf spot (Graphiola phoenicis Moug. Poit.), are becoming more prevalent, while others, such as the Date mite (Bou-Faroua), become rare or absent. On the other hand, when air humidity is low, fungal diseases are absent, while pest and mite attacks are dominant. Air humidity also affects the date quality during the maturation process. At high humidity, fruits become soft and sticky, while at low humidity they become very dry (case of Northern Sudan and in-land plantations). This phenomenon is strengthened when low humidity is coupled with hot and dry winds (called Chili in Tunisia, Chergui in Morocco, N-W in Iraq, etc.). Dry and hot winds cause a rapid maturation process leading to fruit desiccation and the appearance of a yellow or white ring at the fruit base. When air humidity is high during maturation (date plantations in Bahrein, Minab/Iran), the skin of the date fruit shows several cuts or breaks with an edge-blackening (Blacknose), the soft fruits fall to the ground and consequently lose their commercial value.

The number of these breaks and the manner in which they occur (longitudinal, transverse, or irregular) varies between varieties. Deglet Nour's checking occurs mainly near the tip of the fruit. The above effect occurs only when high humidity is experienced immediately before the Khalal stage. After the fruit acquires the Khalal colour, checking no longer occurs. After the flesh softens in the Rutab stage, the skin does not break readily upon contact with moisture, but the fruit absorbs moisture and tends to become sticky and more difficult to handle. After the Tamar stage is reached, air humidity causes little damage to the fruit unless it is neglected. Most commercial date plantations in USA and Israel are not intercropped with any other plants/fruit tree species (citrus, lucerne, etc.) because of the increasing effect of these on the humidity level of the date plantation. The following table illustrates the high relative humidity of four Middle East date plantations and at one place in Namibia. TABLE 29 Examples of relative humidity of various date plantations (at 08:00 am) Place/Country Source: Dowson, 1982. 4.

Wind Compared to other plant species, the date palm shows no damage under windy conditions. In fact, date palm can withstand strong, hot and dusty summer wind and consequently protects the other cultures by breaking the force of the wind and sheltering more susceptible vegetation (Dowson, 1982). Wind is, however, a carrier of dust and sand that adheres to the date fruits in their soft stage (Rutab and Tamar). When the fruits are at their early development stage (green/Habakouk), nearly black-indurated patches are sometimes seen on the fruit because of the wind beating the tender fruits against the hard fronds. Recently planted small offshoots can, however, easily be uprooted by strong winds. In most date growing areas the latter part of the pollination season is usually characterised by severe hot and dry winds which dries out the stigmas of the female flowers. Cold winds disturb the pollen germination. It seems, therefore, that dry wind storms lead to a faster drying of the styles which shortens the time for the pollen to reach the ovule (Reuveni et al., 1986).

The speed of the wind could also have an effect on the pollination efficiency; light winds are beneficial and favour pollination while high speed winds will blow away a great deal of the pollen, especially on palms found at the edges of the plantation. In some cases severe wind could also break the inflorescence's fruit stalk (rachis), blocking the movement of nutrients and finally causing the death of the bunch. It has also been suggested that mites are carried from palm to palm by wind. The falling down of an old date palm may be caused by strong wind but only in the following cases: - If the palm is very tall with a large crown and grows in shallow soil; - If a large number of offshoots are removed form the trunk of a palm at one time, leaving the palm without basal support; and - If rats have gnawed away the roots on one side of the palm. It is highly recommended that wind breaks be planted one to two years before the establishment of any commercial date palm plantation. Beefwood (Casaurina cunninghummiana, or C. glauca) is the most appropriate wind break for the protection of a date palm plantation (Figure 33) since they are both drought and salt tolerant.

5. Light According to Mason (1925b), the growth of a date palm is inhibited by light rays at the violet and yellow end of the spectrum, but enhanced by rays at the other end of the spectrum i.e. red light. These latter rays are most active in promoting photosynthesis. Clouds could reduce light intensity, but unfortunately, the sky is un-clouded in the date growing countries during the ripening period (July to October in Northern Hemisphere and February to May in Southern Hemisphere). Table 30 gives the average number of cloudless days in three famous date growing areas of Algeria (Lasserre, 1922), while Table 31 shows the sunshine and radiation values obtained in Keetmanshoop area (Namibia) for a period length of 37 years (1948-1985). TABLE 30 Average number of cloudless days in Algeria Place Mean 320.4 In conclusion, the five important factors which determine the suitability of a site for date palm culture, are temperature, rain, humidity, light and wind.

The effect of these factors on the growth and productivity of date palm is to be considered as a combination of all the factors and not each one separately. Furthermore, because of the nature of date palm, its growth is not as easy as some other plant species and attention should be given to the following characteristics: - Date palm cannot be classed as arenaceous, nor aquatic. Although frequently found growing in sand, its roots are characterised by air spaces similar to the ones in Banana roots, but it also grows well where the subsoil water is close to the surface. - It is not a true halophyte despite its healthy growth in exceedingly salty places, as it grows better when the soil and water are sweet. - It is not a xerophyte; although it has a thick waxy cuticle, leaflets with the two halves of their upper surfaces to the sun, reduced leaf surface, efficient insulation of the growing point and its trunk's vascular bundles; it requires a copious water supply. Figure 29.

Effect of low temperatures on: A - Five years old Barhee palm; Note the yellowing and drying out of pinnae margins (-6°C); B - Eight months tissue culture Medjool plants: Note the destruction of large part of the leaflet (-3°C) Figure 30. Frost damage on date palm female inflorescence Figure 31. Protection of female inflorescences with craft paper bags at Hardap Research Station (Namibia) Figure 32. Protection unit made of craft paper to avoid rain damage to date fruit bunches (USA) Figure 33. Wind breaks (Casaurina cunninghummiana) used for the protection of a commercial date plantation (Naute, Namibia)

Question: Which country grows the most dates?
Answer: Iraq