''Malus sieversii'' is a
wild apple
''Malus sieversii'' is a wild apple native to the mountains of Central Asia in southern Kazakhstan. It has recently been shown to be the primary ancestor of most cultivars of the domesticated apple (''Malus domestica''). It was first described as ...
native to the mountains of
Central Asia
Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...
in southern
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
. It has recently been shown to be the primary ancestor of most
cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...
s of the domesticated
apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...
(''
Malus domestica
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...
''). It was first described as ''Pyrus sieversii'' due to its similarities with
pear
Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the p ...
s in 1833 by
, a German naturalist who saw them growing in the
Altai Mountains
The Altai Mountains (), also spelled Altay Mountains, are a mountain range in Central Asia, Central and East Asia, where Russia, China, Mongolia and Kazakhstan converge, and where the rivers Irtysh and Ob River, Ob have their headwaters. The m ...
.
''Malus sieversii'' grows in many different habitats.
They prefer high temperatures and short winters, but they are also found in the Tian Shan Mountains with long and harsh winters.
They are distributed mainly within the Yili valley as the damp climate is suitable for their growth.
It is a
deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
growing , very similar in appearance to the domestic apple. Its pollen grains vary in size and are seen to be ovular when dry and spherical when swelled with water.
Its
fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
is the largest of any species of ''Malus'' except ''domestica'', up to 7 cm in diameter, equal in size to many modern
apple cultivars
Over 7,500 cultivars of the culinary or eating apple (''Malus domestica'') are known. Some are extremely important economically as commercial products, though the vast majority are not suitable for mass production. In the following list, use for ...
. Unlike domesticated varieties, its leaves go red in autumn: 62.2% of the trees in the wild do this compared to only 2.8% of the regular apple plant or the
2,170 English cultivated varieties.
The species is now considered vulnerable to
extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
.
Characteristics and growth
''M. sieversii'' has the capability to reproduce vegetatively as they form root suckers, or
basal shoot
Basal shoots, root sprouts, adventitious shoots, and suckers are words for various kinds of shoots that grow from adventitious buds on the base of a tree or shrub, or from adventitious buds on its roots. Shoots that grow from buds on the base of ...
s.
The clonal individual grows from the adventitious bud on the root, with identical genetic materials of the mother plant.
It was originally believed that wild apples produce root suckers only when upper plant parts are damaged.
However, more evidence suggested root-sucker growth occurs in healthy plants as a dispersal aid.
For wild apples, proper development of root suckers requires certain humidity and aeration levels in the surface soil, where the mother root is located. Successful root-sucker growth also depends on shoot arrangement, time of growth and health conditions of the mother plant.
Genetics of
self-incompatibility
Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals ...
, the system for preventing self-fertilization in angiosperms, have also been studied for ''M. sieversii''.
Its genetic diversity in relation to self-incompatibility is substantially less when compared to its close relative, ''
Malus sylvestris
''Malus sylvestris'', the European crab apple, is a species of the genus ''Malus'', native to Europe. Its scientific name means "forest apple" and the truly wild tree has thorns.
Description
Wild apple has an expanded crown and often appears mor ...
''.
Although ''M. sieversii'' lacks this diversity, they can survive in the wild without intervention as long as no more diversity loss occurs.
The leading theory for this lack of diversity is due to a major
population bottleneck
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as specicide, widespread violen ...
during the
Last Glacial Maximum
The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent.
Ice sheets covered much of Northern North America, Northern Eur ...
which caused wild ''M. sieversii'' populations to scale back into a smaller area within the Yili Valley.
Growth cycle
The growth cycle of ''M. sieversii'' could be divided into several stages from germination to developing fruit bearing trees, and to the death of aged trees.
* Period I starts from seed germination to the development of vegetative tree parts, and to the first round of fruiting.
A typical apple tree reaches age 6 to 8 in this period. Prominent primary growth and a significant number of root sucker growth are seen in this period.
* Period II involves more growth and fruit bearing.
Wild apple trees usually reach age 10 to 12 in this period.
The number of fruits increase significantly as prominent secondary growth and branching take place.
* Period III involves more growth and fruit bearing.
Wild apple trees enter regular fruiting and reach maximum fruit bearing in this period, and usually reach age 25 to 30.
Decreased branching rate, and less growth of crown periphery are seen.
A lot of vegetative growth is contributed by basal shoots (root suckers).
* Period IV is fully fruit bearing.
Development of trees fully ceases in this stage and they reach around 60 to 70 years of age.
Branching decreases as they slowly die off from the base to the periphery. After age 60 to 70, trees experience rapid desiccation of the branches, then death.
History and importance
''Malus sieversii'' has previously been identified as the main contributor to the genome of the cultivated apple (''Malus domestica''), on the basis of
morphological,
molecular
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...
, and historical evidence. Fruit traits including crispness, more flavour intensity and fruit weight have undergone differential selection by humans to produce ''Malus domestica'' as seen today. The dispersal of ''M. sieversii'' and its progeny throughout history can be attributed to the
Silk Road
The Silk Road () was a network of Eurasian trade routes active from the second century BCE until the mid-15th century. Spanning over 6,400 kilometers (4,000 miles), it played a central role in facilitating economic, cultural, political, and reli ...
.
A
DNA analysis
Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...
in 2010 confirmed ''M. sieversii'' as the progenitor of the cultivated apple. It has a highly variable genetic diversity therefore it is the genetic source for abiotic and biotic stress tolerance, many disease resistance and unique fruit traits.
Almaty
Almaty (; kk, Алматы; ), formerly known as Alma-Ata ( kk, Алма-Ата), is the List of most populous cities in Kazakhstan, largest city in Kazakhstan, with a population of about 2 million. It was the capital of Kazakhstan from 1929 to ...
, the largest city in
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
, and formerly its capital, derives its name from the
Kazakh word for "apple" (Alma), and is often translated as "full of apples" (the region surrounding Almaty is home to forests of ''Malus sieversii''); ''alma'' is also "apple" in other
Turkic languages
The Turkic languages are a language family of over 35 documented languages, spoken by the Turkic peoples of Eurasia from Eastern Europe and Southern Europe to Central Asia, East Asia, North Asia (Siberia), and Western Asia. The Turkic languag ...
, as well as in
Hungarian.
The threat of extinction
After the collapse of the USSR and the closure of the Gardening Development Program, the local population began to actively cut down wild gardens in the Zailiyskiy Alatau. The vacated territories are used for building houses and grazing animals.
Planting cultivated apple varieties in private households close to wild groves causes crossbreeding.
Renewed interest
These and other ''Malus'' species have been used in some recent breeding programmes to develop apples suitable for growing in harsh climates unsuitable for ''M. domestica'', mainly for increased cold tolerance.
A study in 2020 has discovered various gene inserts involved in dormancy and cold resistance features, such as
heat shock protein
Heat shock proteins (HSP) are a family of proteins produced by cells in response to exposure to stressful conditions. They were first described in relation to heat shock, but are now known to also be expressed during other stresses including expo ...
s, in wild apples.
In addition, desirable traits such as late flowering, early fruit maturity, short juvenility and stooling capability were studied by many breeding programs.
''Malus sieversii'' has recently been cultivated by the
United States Agricultural Research Service, in hopes of finding genetic information of value in the breeding of the modern apple plant. Some, but not all, of the resulting trees show unusual disease resistance. The variation in their response to disease on an individual basis is, itself, a sign of how much more genetically diverse they are than their domesticated descendants. For instance, wild apples were found to have multiple blue mold resistant genes, specifically against ''
Penicillium expansum
''Penicillium expansum'' is a psychrophilic blue mold that is common throughout the world in soil. It causes Blue Mold of apples, one of the most prevalent and economically damaging post-harvest diseases of apples.
Though primarily known as a di ...
''. The USDA Plant Genetic Resources Unit (PGRU) also conducted phenotypic analysis on ''M. sieversii'' seedlings, and has identified various pathogenic resistance including
apple scab
Apple scab is a common disease of plants in the rose family ( Rosaceae) that is caused by the ascomycete fungus ''Venturia inaequalis''. While this disease affects several plant genera, including ''Sorbus, Cotoneaster,'' and '' Pyrus'', it is m ...
,
fire blight
Fire blight, also written fireblight, is a contagious disease affecting apples, pears, and some other members of the family Rosaceae. It is a serious concern to apple and pear producers. Under optimal conditions, it can destroy an entire orchard ...
, and
cedar apple rust
''Gymnosporangium juniperi-virginianae'' is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples (''Malus'') and Eastern red cedar ('' Juniperus virginiana'') coexist, cedar apple rust can be a des ...
.
A research in 2001 found various insect resistances within ''M. sieversii'' seedlings, and has identified instances for further research on its resistance for
apple maggot
The apple maggot (''Rhagoletis pomonella''), also known as the railroad worm (but distinct from the '' Phrixothrix'' beetle larva, also called railroad worm), is a species of fruit fly, and a pest of several types of fruits, especially apples. ...
s and apple leaf curling midges.
Effects of heat on ''M. sieversii'' were also studied in hot and arid regions, and they were found to be considerably drought tolerant and sunburn resistant.
Red-fleshed apples
''Malus sieversii'' has been recently used as a critical source in the breeding of red-fleshed apples, due to its high genetic variability. This is seen as they are used to improve the stress resistance towards drought, cold, and pests of cultivated apple species.
Some neglected characteristics of ''M. sieversii'', such as high-flavonoid contents (especially
anthocyanin
Anthocyanins (), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart gave the name Anthokyan to a chemical compo ...
) and short juvenile phases, have recently been used for red-fleshed apple breeding since traditional red-fleshed apples are not rich in these flavonoids.
Using ''M. sieversii'' for breeding due to its high anthocyanin content has numerous benefits, including preventing cardiovascular disease and protecting against liver damage.
The variant of ''M. sieversii'', ''Malus sieversii f. niedzwetzkyana'', has been emphasized for the use of breeding red-fleshed apples since it has red flowers, fruit skin, and pulp; in addition to its high anthocyanin content.
When breeding ''Malus sieversii f. niedzwetzkyana'', it was found that light results in higher anthocyanin production than those bred in the dark.
Hybrids of ''Malus sieversii'' have also been an interest for breeders of red-fleshed apples.
Conservation
''Malus sieversii'' has been designated as second conservation priority in the China Plant Red Data Book, and has been marked as vulnerable by the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
(IUCN).
Human activities and natural disasters are the major contributors to the decline of ''M. sieversii'' natural population.
Fungal pathogens, such as ''
Phytophthora plurivora
''Phytophthora plurivora'' is a very aggressive soil-borne plant pathogen, with worldwide distribution and a wide variety of hosts.
It belongs to the class of oomycetes and is often described as a ‘fungal-like’ organism since they form a h ...
'' and ''
Alternaria alternata
''Alternaria alternata'' is a fungus which has been recorded causing leaf spot and other diseases on over 380 host species of plant. It is an opportunistic pathogen on numerous hosts causing leaf spots, rots and blights on many plant parts.
It ...
'', also play a major role in the decline of ''M. sieversii'' populations, by degrading vegetative parts such as the fine root systems.
This immune vulnerability makes ''M. sieversii'' become susceptible to more parasites, such as pathogenic insects ''
Agrilus
''Agrilus'' is a genus of jewel beetles, notable for having the largest number of species (about 3000) of any single genus in the animal kingdom.
'' Agrilus aureus''
Species
* '' Agrilus abantiades'' Descarp ...
mali'', to further destroy the population.
Ex situ conservation
Svalbard GLOBAL SEED BANK, an ''ex situ'' conservation.
''Ex situ'' conservation literally means, "off-site conservation". It is the process of protecting an endangered species, variety or breed, of plant or animal outside its natural habitat; ...
, or seed banking, is believed to be a feasible long-term resolution to protect its genetic diversity, and has been seen in the United States using seeds collected from Kazakhstan and thee Kyrgyz Republic.
In situ conservation
''In-situ'' conservation is the on-site conservation or the conservation of genetic resources in natural populations of plant or animal species, such as forest genetic resources in natural populations of Teagan species. This process protects th ...
was also found with barbed wire fences being placed around regions distributed with ''M. sieversii,'' as seen in areas within Xinyuan, China.
A study in 2016 has shown the effectiveness of protecting ''M. sieversii'' populations in situ through
stratification
Stratification may refer to:
Mathematics
* Stratification (mathematics), any consistent assignment of numbers to predicate symbols
* Data stratification in statistics
Earth sciences
* Stable and unstable stratification
* Stratification, or str ...
and seed coat removal.
Also, in situ enclosures are more effective in higher elevations as they are at less risk of human and insect injuries.
Aside from traditional conservation methods,
biofertilizer
A biofertilizer is a substance which contains living micro-organisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of prim ...
has shown effective results inhibiting fungal pathogen, ''
Alternaria alternata
''Alternaria alternata'' is a fungus which has been recorded causing leaf spot and other diseases on over 380 host species of plant. It is an opportunistic pathogen on numerous hosts causing leaf spots, rots and blights on many plant parts.
It ...
'' in wild apple trees. It does this by improving antioxidant capability of wild apple trees following the infection, promoting root growth and enhancing soil metabolism.
Recently, a combination of innovative methods including cloning and plant hormone treatment has also shown effective results in regenerating wild apple populations.
Wild apple trees were heavily lumbered for economical and agricultural uses in the mountains of Kazakhstan during the 1800s.
Wild apple forests were turned into pastureland, which greatly changed the soil covering, and damaged young seedlings and roots.
Prickly shrubs, such as eglantine and
barberry
''Berberis'' (), commonly known as barberry, is a large genus of deciduous and evergreen shrubs from tall, found throughout temperate and subtropical regions of the world (apart from Australia). Species diversity is greatest in South America a ...
exhibiting symbiotic relationships with wild apples by shielding them from predators were also cut.
This further worsened the growing condition for wild apples, and severely weakened
root suckers and therefore
vegetative propagation
Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is any form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or speci ...
.
Gallery
File:Malus sieversii in Zhongar-Alatau NP-1.jpg, ''Malus sieversii'' trees in Zhongar-Alatau National Park
Zhongar-Alatau National Park ( kk, Жоңғар Алатауы ұлттық паркі, ''Joñğar Alatauy ūlttyq parkı''), also Jungar Alatau, or Dzungurian Alatau, was created in 2010 to protect the unique ecology of the Dzungarian Alatau, an ...
Image:Botanischer Garten Berlin-Dahlem 10-2014 photo08 Malus sieversii.jpg, A tree in Berlin-Dahlem Botanical Garden
The Berlin Botanic Garden and Botanical Museum (german: Botanischer Garten und Botanisches Museum Berlin) is a botanical garden in the locality of the borough of , Berlin, Germany. Constructed between 1897 and 1910 under the guidance of archi ...
in autumn
Image:96apple.jpg, Fruit
References
* Listed as Vulnerable (VU B1+2c v2.3)
External links
*Wild apples in Kazakhstan
1995an
US Agricultural Research Service expeditions
*http://www.findarticles.com/p/articles/mi_m1134/is_8_110/ai_79051530
*Malus sieversi
{{Taxonbar, from=Q728769
Malus, sieversii
Apples
Flora of temperate Asia
Fruits originating in Asia
Flora of Kyrgyzstan
Flora of Kazakhstan
National symbols of Kazakhstan
Flora of Uzbekistan
Flora of Afghanistan
Flora of Xinjiang
Flora of Tajikistan
Vulnerable flora of Asia