Morus spp.


Scientific name

Morus spp. L. (Morus alba L., M. nigra L. and M. rubra L.)

Most of the cultivated varieties are white mulberry (Morus alba L.), black mulberry (M. nigra L.), Indian mulberry (M. indica) and in North America the American or red mulberry (M. rubra L.).  Hybrid forms exist between Morus alba and M. rubra and others.  There are many other species: Korean mulberry (Morus australis), Himalayan mulberry (M. laevigata).

Synonyms

  

Family/tribe

Family: Moraceae.

Common names

mulberry, common mulberry, silkworm mulberry (English);  morera or mora (Spanish);  moreira (Portuguese);  mûrier (French).

Morphological description

The common mulberry is a handsome deciduous tree, 10-25 m tall, of rugged, picturesque appearance, forming a dense, spreading head of branches usually wider than the height of the tree, springing from a short, rough trunk.  The form of the tree can vary from pyramidal to drooping.  The simple, alternate, stipulate, petiolate, light green leaves are cordate at their base but very variable in form, even on the same tree;  some are un-lobed while others may be almost palmate.  Flowers are unisexual, borne in the axils of leaves or on spurs on separate spikes, or catkins, which are small, more or less cylindrical and trees may be monoecious or dioecious .  Fruits are collective, fleshy, white, lavender, deep red to black.

Distribution

Native to:
Asia:  China.

Other:
It has now spread from the temperate areas of northwest and central Asia, Europe and North America, through the tropics of Asia, Africa and Latin America, to the southern hemisphere (southern Africa and South America).  There are mulberry varieties for many environments, from sea level to altitudes of 4,000 m, and from the humid tropics to semi-arid lands.  In the Near East with 250 mm of annual rainfall and southwest of the USA, mulberry is also produced under irrigation.

Uses/applications

Mulberry leaves have been the traditional feed for the silk worm.  There is evidence that sericulture started about 5,000 years ago and hence the domestication of mulberry.  The main use of mulberry globally is as feed for the silk worm, but depending on the location, it is also appreciated for its fruit (consumed fresh, in juice or as preserves), as a delicious vegetable (young leaves and stems), for its medicinal properties in infusions (mulberry leaf tea), for landscaping and as animal feed.  There are several places where mulberry is utilised traditionally as a feed in mixed forage diets for ruminants.
The berries, called sorosis have been used in traditional fabric dyeing.  Purple and red are common colours produced with mulberry.  It is traditionally used to dye wool.
Mulberry is well suited for use as a fodder where it can be grown opportunistically around house-compounds, on spare pieces of land and along field edges.  Integration of fish, livestock, and crop production in China has been refined for over 2,000 years.  The system recycles resources, reduces organic pollution (livestock and poultry manure are good organic fertilizers for fish farming), and combines fish farming with mulberry cultivation for raising silkworms.  The silkworm pupae are used as fish feed, and the worm faeces and wastewater from silk processing as pond fertilizers.  Pond silt is used as fertilizer for fodder crops, which can in turn be used to feed livestock, poultry, and fish.

Ecology

Soil requirements

Mulberries grow better in a well-drained neutral soil, preferably a deep loam.  Shallow soils such as those frequently found on chalk or gravel are not recommended.  The white mulberry, and to a lesser extent the red mulberry, are quite tolerant of drought , pollution and poor soil.  The white mulberry is considered a weed in many parts of the country including urban areas.  The black mulberry is more fastidious, faring less well in cold climates or areas with humid summers.

Moisture

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Tolerates drought but if the roots become too dry during drought the fruits drop before ripening.

Temperature

Mulberry grows well in temperate areas but loses its leaves in the winter.  The white mulberry is the most cold hardy of the three species, although this varies from one clone to another.  Some are damaged at 25° F, while others are unfazed at -25° F.  Red mulberries are hardy to sub-zero temperatures.  The black mulberry is the least cold hardy of the three, although again cold tolerance seems to depend on the clone.  In general it is limited to USDA Hardiness Zone 7 (0°-10° F average minimum) or warmer.  In the tropics it grow all year around.

Light

Mulberries require full sun for good production.  Maximum yields in Costa Rica have been obtained in areas with plenty of sunlight.

Reproductive development

No information available.

Defoliation

Mulberries respond well to coppicing .  In temperate areas foliage is harvested twice a year.  In the tropics the most appropriate cutting interval is 90-120 days.  Cutting should not be done too close to the trunk since flush cuts are larger than they need to be and delay the sealing of the wound.

Fire

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No information available.

Agronomy

Establishment

The most common planting method worldwide is by stem cuttings, but in certain places seed is preferred.  For fruit production, plants should be spaced at about 3-4 m apart, but can be planted much closer at 75 cm spacing for cut and carry forage production for either silk worms or livestock.  Micro-stakes, with only one bud, take well in humid and warm conditions.  Hardwood, softwood and root cuttings also are suitable methods for propagating mulberries.  Softwood cuttings of white mulberries root easily when taken in mid-summer and treated with rooting hormone.  Red mulberries root less easily.  Black mulberries are also somewhat difficult to propagate since they tend to bleed a lot.  The advantages of stem reproduction (cloning) are certainty of production characteristics, practicality in obtaining the material and ease of planting.  Male plants might be preferred when introducing foreign germplasm to new locations since this prevents involuntary expansion.  As in most perennial forages, the time and the establishment cost (mainly for land preparation, planting and weed control) are the critical aspects of the successful introduction of mulberry.
Mulberries can also be grown from seed.  Seed should be sown as soon as extracted from the fruit, although white mulberry seeds germinate better after storage for one to three months before planting.  Seeds should be planted near the surface with a thin layer of soil and ashes spread over them in moist soil.  Seeds germinate in 9-14 days, depending on the season.  When seedlings are about 7.5 cm tall, they are thinned and weeded.  As is the case with other tropical perennial forages for cut-and-carry systems, planting by seed assures deeper roots with greater capacity to find water and nutrients, which eventually results in higher biomass production and greater longevity.  Seeds might be the most acceptable way of transporting, quarantine and store selected materials.
Sprig budding is the most common method for grafting mulberries.  A T-cut is made in the rootstock and a smooth, sloping cut is made on the lower end of the scion.  The scion is then inserted into the T and wrapped and sealed.  Other types of grafts are also usually successful, although there may be incompatibility between white and black mulberries.

Fertiliser

Mulberry for forage responds very well to fertilisation.
All the required nutrients for mulberry growth must come from the soil, since it does not fix atmospheric nitrogen.  In pure stands, mineral and organic fertilisers (animal and vegetable manures) must be used to replenish the nutrients removed with the foliage in order to maintain a sustainable production.  The association with legumes with effective N-fixing rhizobium can reduce N inputs and may be the most desirable combination for some farms, but even when recycling nutrients in animal manures, extra chemical fertilisers are required for maximum.  Responses of mulberry to N fertilisers have been clearly demonstrated, both in inorganic and organic forms, with better responses to the latter, the nitrogen level in soils is the major factor for mulberry growth.

Compatibility (with other species)

Mulberry has been tried for direct browsing in combination with grasses and clovers in Italy.  In the tropics, it combines well with Gliricidia sepium under cut-and-carry systems and under Erithrina poeppigiana.

Companion species

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A natural association of mulberry and livestock occurs in regions (e.g Near East and Central Asia) where mulberry trees are kept for fruit production.  Fallen leaves in the autumn are consumed by domestic animals.  Since fruit ripening happens in late spring or early summer, it may be possible to harvest leaves for forage one or more times before the winter.
The only suggestion of utilising mulberry for direct grazing was a complementary association with clover (Trifolium subterraneum) for sheep and cattle grazing in Tuscany (Italy).  Mulberry benefits from the N fixation by the clover and contributes with high quality forage during the summer.  The association produces more forage over a longer period than the individual pure-stands.

Pests and diseases

Literature describes many pests and diseases of mulberry in silk producing temperate areas, but generally mulberry is a very healthy crop.  Nematode attacks have been observed in Yucatan, Mexico, under rocky calcareous soils under irrigation with pig slurry.  Wild iguanas have been seen in mulberry plantations.  Leaf-cutting ants can be a problem in certain areas.
 The ripe fruit is very attractive to birds, but there is usually enough fruit left over for harvesting.

Ability to spread

Mulberry trees are very easy to propagate and to transplant.  Fruit (seed) bearing plants can be spread through birds.

Weed potential

Its weed potential is very low since propagation by birds is the only viable way.

Feeding value

Nutritive value

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Chemical composition of mulberry fractions have been taken from various authors.  Crude protein content in leaves varies from as low as 15%-28% depending on the variety, age of the leaves and growing conditions.  In general, crude protein values can be considered similar to most legume forages.  Fibre fractions are low in mulberry leaves compared to other foliages.  Reported lignin (acid detergent lignin ) contents of 8.1% and 7.1% for leaves and bark, respectively.  A striking feature of mulberry leaves is the mineral content, with ash values up to 25%.  Typical calcium contents are around 1.8-2.4% and phosphorus 0.14-0.24%.  Potassium values of 1.90-2.87% in leaves and 1.33-1.53% in young stems, and magnesium contents of 0.47-0.63% for leaves and 0.26-0.35% for young stems.
The digestibility of mulberry leaf:  in vivo (goats) 78.4-80.8% and in vitro are very high (89.2%) and total digestibility is equivalent to that of most tropical forages.  The degradation characteristics of mulberry, determined by the nylon bag technique, indicated leaves would be completely degraded if they remained in the rumen for enough time.
The average amino acid composition and N content of 119 mulberry varieties grown experimentally in Japan.  Essential amino acids are over 46 % of total amino acids.  The average nitrogen (N) is 16.6% of the total molecular weight of the mulberry amino acids (plus ammonia), and thus the converting factor from N to mulberry protein is 6.02.  The 204.3 mg of amino acids/g of protein is equivalent to 3.47% N, which is 80% of total N in mulberry leaves.  Once tryptophane is subtracted, the difference, a non-protein fraction, is likely to be composed of nucleic acids and other unidentified N compounds.

Palatability/acceptability

One of the main features of mulberry as forage is its high palatability .  Small ruminants avidly consume the fresh leaves and the young stems first, even if they have never been exposed to it before.  Then, if the branches are offered unchopped, they might tear off and eat the bark.  Cattle consume the whole biomass if it is finely chopped.  Animals initially prefer mulberry to other forages when they are offered simultaneously, and even dig through a pile of various forages to look for mulberry.

Toxicity

There have been no reports of toxicity, and only apparent few cases of bloating with cattle in Japan.

Production potential

Dry matter

Biomass production:
Total:  25-47 t/ha./year.
Edible:  15-35 t/ha./year.

Animal production

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There is a report of ad libitum dry matter intake of 4.18% of liveweight (average of three lactating goats), which is much higher than in other tree fodders, the dry matter intakes of mulberry leaves of 3.44% of body weight in sheep under experimental conditions.  Goats can produce between 15,000-20,000 litres of milk/ha in mulberry based feeding systems.  In a comparative study, higher daily dry matter intakes of mulberry leaves were seen in sheep than in goats (3.55 vs. 2.74 kg DM/100kg body weight).  In Costa Rica, liveweight gains of bulls belonging to the Romosinuano breed (a criollo type) fed elephant grass, increased to over 900g/day when mulberry was offered as a supplement at 1.7% of their body weight on a DM basis.  Growing Zebu x Brown Swiss steers being fed increasing levels of mulberry as supplement to a sorghum silage diet.  Although the growing rates with the highest mulberry level are not impressive (195g/day), most likely due to the poor quality of the silage , this trial shows the high nutritive value of the supplement.  Other small herbivores, like guinea pigs, iguanas and snails, could also be fed mulberry leaves.  In fact, wild green iguanas (Iguana iguana) came to feed on recently established mulberry fields in Costa Rica.
A combination of mulberry and Trichantera gigantea leaves, as the protein source, and blocks made of molasses, cassava root meal and rice bran, as the energy source, gave better reproduction and growth performance than a diet of commercial concentrates and grass supplemented Angora rabbits, receiving pelleted diets, with mulberry leaves ad libitum and obtained intakes of mulberry equivalent to 29-38% of the total intake.  This level significantly reduces feed cost.  Fed mulberry leaves as the sole ration for adult rabbits.  They found daily intakes of 68.5g for dry matter, 11.2g for crude protein and 175kcal for digestible energy (equivalent to 2.55Mcal of digestible energy per kg).  The digestibility values were 74% for crude protein, 59% for crude fibre and 64% for dry matter.  The authors concluded that mulberry leaves provided enough nutrients for maintenance.  Shade-dried M. indica leaf meal in the mash of laying hens has been found to improve egg yolk colour and to increase egg size and production with the inclusion up to 6%) in laying hens.

Genetics/breeding

The diploid M. alba (2n = 2x = 28) is the species most widely spread, but polyploid varieties, which originated in various research stations in Asia, show greater leaf yields and quality.  In general, polyploid varieties have thicker and larger leaves with darker green colour, and produce more leaves.  Triploid varieties have been found especially among Morus bombysis Koidz.  M. cathayana Hemsl. has tetraploid , pentaploid and hexaploid varieties.  Both M. serrata Roxb., indigenous to India, and M. tiliaefolia Makino, originally from Japan and Korea, are known to be hexaploid.  M. boninensis Koidz. is a tetraploid being endangered due to cross contamination with M. acidosa Griff. M. nigra L. is dexoploid (2n = 308), the largest number of chromosomes among phanerogams.
They are wind pollinated and some cultivars will set fruit without any pollination.  Cross-pollination is not necessary.  Male catkins are generally longer than female ones and are loosely arranged;  after shedding pollen they dry and drop off.  The juicy drupelets formed by the individual flowers on the catkin combine to form a sorosis, the characteristic mulberry fruit.

Seed production

Fruits are picked or shaken on sheets when ripe.  Mulberry seeds should be removed from the ripe fruit as soon as ready by squashing with plenty of water to separate seed from pulp.  The seed can be dried and stored or stratified in sand for several months although immediate sowing is often recommended.

Herbicide effects

No information available.

Strengths

  • Wide variation in germplasm to suit many growing conditions from the temperate areas to the humid tropics.
  • It grows in a variety of soils.
  • It can produce large quantities of nutritious forage , particularly in tropical areas.

Limitations

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  • A good system for direct browsing is yet to be developed.

Other comments

Mulberry is also a widely used traditional folk remedy, used for "aphtha, armache, asthma, bronchitis, bugbite, cachexia, cold, constipation, cough, debility, diarrhea, dropsy, dyspepsia, edema, epilepsy, fever, headache, hyperglycemia, hypertension, inflammation, insomnia, melancholy, menorrhagia, snakebite, sore throat, stomatitis, tumours, vertigo, and wounds".
Mulberry twigs are used for making baskets, the sticks as beanpoles, and the wood for fuelwood, sporting goods (it's springy, like ash) and fine furniture.  In Japan, the traditional "chashaku" green tea scoop used in semi-formal tea ceremonies is made of mulberry wood.  If it's not mulberry then it's only an informal one.  (Formal chashaku are supposed to be ivory.)

Selected references

Benavides, J.E. (1999) UtilizaciÓn de la morera en sistemas de producciÓn animal. En: Sánchez, M.D. & Rosales, M. Agroforestería para la producciÓn animal en Latinoamérica. Memorias de la conferencia electrÓnica. Estudio FAO ProducciÓn y Sanidad Animal 143. pp. 275-281. (FAO, Rome).
Boschini, C.F. (2002) Establishment and management of mulberry for intensive fodder production. In: Sánchez, M.D. (ed.) 2002. Mulberry for Animal Production . Animal Production and Health Paper 147. pp. 115-122. (FAO, Rome).
Hiroaki Machii, Akio Koyama and Hiroaki Yamanouchi (2002) Mulberry Breeding, Cultivation and Utilization in Japan. In: Sánchez, M.D. (ed.) 2002. Mulberry for Animal Production . Animal Production and Health Paper 147. pp. 63-71. (FAO, Rome).
Kamimura, C., Koga, S., Hashimoto, A., Matsuishi, N., Torihama, Y., Nishiguchi, T. and Shinohara, K. (1997) Studies on the factors influencing the mulberry (Morus alba) productivity in fields. Journal of Sericultural Science of Japan, 66, 176-191.
Sánchez, M.D. ed. (2002).  Mulberry for animal production . FAO Animal Production and Health Paper 147.  Food and Agriculture Organization of the United Nations, Rome, Italy.
Shayo, C.M. (1997) Uses, yield and nutritive value of mulberry (Morus alba) trees for ruminants in the semi-arid areas of central Tanzania. Tropical Grasslands, 31, 599-604.

Internet links

Cultivars

Cultivars

Country/date released

Details

'Black Persian' USA M. nigra.  Large black fruit, over 25 mm long and almost as wide.  Juicy with a rich, subacid flavor.  The tree is fairly drought -resistant once established.
'Collier' USA M. alba x M. rubra.  Medium-sized, purplish-black fruit, 30 mm long and 10 mm in diameter.  Flavor sweet, with just a trace of tartness.  Quality very good, on par with 'Illinois Everbearing'.  Ripens over a long period.  Tree of medium size, spreading, relatively hardy, very productive.
'Downing' USA The original 'Downing' was a M. alba var. multicaulis plant grown from seed sown about 1846.  The fruit was black with excellent flavor and ripened from June to September.
'K.M.' India West Bengal selection which gives 50% more leaves than local types, and is popular in Mysore for grafting purposes.
'Pakistan' USA Originated in Islamabad, Pakistan.  Extremely large ruby-red fruit 65-90 mm long and 10 mm in diameter.  Flesh firmer than most other named cultivars.  Sweet with a fine balance of flavors.  Quality excellent.  Tree spreading with large heart-shaped leaves.  Recommended for the warmer areas.
'Russian' (M. tatarica) USA Introduced into Europe from China about 1,500 years ago.  Fruit reddish-black, of good quality when completely ripe.  Tree bushy, to 10 m tall, very hardy and drought resistant and used as a rootstock.  Planted widely for windbreaks and wildlife food.
'Shangri-La' USA Originated in Naples, Florida. Large, black fruit.  Good mulberry for warmer areas but hardy.  Tree has very large, heart-shaped leaves.
'Tehama' ('Giant White') USA Originated in Tehama County, California.  Very large, white-colored, plump fruit, 70 mm in length and 12 mm wide.  Very sweet, succulent, melting flesh.  Attractive, large-leaved tree .  Probably best adapted to mild winter areas.

Promising accessions

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Promising accessions

Country

Details

None reported.