Malus sieversii | |
---|---|
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Rosales |
Family: | Rosaceae |
Genus: | Malus |
Species: | M. sieversii |
Binomial name | |
Malus sieversii | |
Synonyms [2] [3] [4] | |
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 Pyrus sieversii due to its similarities with pears in 1833 by Carl Friedrich von Ledebour, a German naturalist who saw them growing in the Altai Mountains. [5]
Malus sieversii grows in many different habitats. [5] They prefer high temperatures and short winters, but they are also found in the Tian Shan Mountains with long and harsh winters. [5] They are distributed mainly within the Yili valley as the damp climate is suitable for their growth. [6] [7]
It is a deciduous tree growing 5 to 12 metres (16 to 39 ft), 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. [7] Its fruit is the largest of any species of Malus except domestica, up to 7 cm in diameter, equal in size to many modern apple cultivars. Unlike domesticated varieties, its leaves go red in autumn: 62% 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. [8] The species is now considered vulnerable to extinction.
M. sieversii has the capability to reproduce vegetatively as they form root suckers, or basal shoots. [5] The clonal individual grows from the adventitious bud on the root, with identical genetic materials to the mother plant. [5] It was originally believed that wild apples produce root suckers only when upper plant parts are damaged. [5] However, more evidence suggested root-sucker growth occurs in healthy plants as a dispersal aid. [5]
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. [5]
Genetics of self-incompatibility, the system for preventing self-fertilization in angiosperms, have also been studied for M. sieversii. [9] Its genetic diversity in relation to self-incompatibility is substantially less when compared to its close relative, Malus sylvestris . [9] Although M. sieversii lacks this diversity, it can survive in the wild without intervention as long as no more diversity loss occurs. [9] The leading theory for this lack of diversity is due to a major population bottleneck during the Last Glacial Maximum which caused wild M. sieversii populations to scale back into a smaller area within the Yili Valley. [9] [10]
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. [5]
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, and historical evidence. [11] Fruit traits including crispness, more flavour intensity and fruit weight have undergone differential selection by humans to produce Malus domestica as seen today. [12] The dispersal of M. sieversii and its progeny throughout history can be attributed to the Silk Road. [13] A DNA analysis in 2010 confirmed M. sieversii as the progenitor of the cultivated apple. [14] 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. [15]
Almaty, the largest city in Kazakhstan, 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, as well as in Hungarian.[ citation needed ]
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.[ citation needed ]
Planting cultivated apple varieties in private households close to wild groves causes crossbreeding. [16]
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. [17] A study in 2020 has discovered various gene inserts involved in dormancy and cold resistance features, such as heat shock proteins, in wild apples. [15] In addition, desirable traits such as late flowering, early fruit maturity, short juvenility and stooling capability were studied by many breeding programs. [18]
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 . [19] The USDA Plant Genetic Resources Unit (PGRU) also conducted phenotypic analysis on M. sieversii seedlings, and has identified various pathogenic resistance including apple scab, fire blight, and cedar apple rust. [20] A research in 2001 found various insect resistances within M. sieversii seedlings, and has identified instances for further research on its resistance for apple maggots and apple leaf curling midges. [13] 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. [13] [21]
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. [22] Some neglected characteristics of M. sieversii, such as high-flavonoid contents (especially anthocyanin) and short juvenile phases, have recently been used for red-fleshed apple breeding since traditional red-fleshed apples are not rich in these flavonoids. [22] Using M. sieversii for breeding due to its high anthocyanin content has numerous benefits, including preventing cardiovascular disease and protecting against liver damage. [23] 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. [24] [23] When breeding Malus sieversii f. niedzwetzkyana, it was found that light results in higher anthocyanin production than those bred in the dark. [23] Hybrids of Malus sieversii have also been an interest for breeders of red-fleshed apples. [25]
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 (IUCN). [26]
Human activities and natural disasters are the major contributors to the decline of M. sieversii natural population. [5] Fungal pathogens, such as Phytophthora plurivora and Alternaria alternata , also play a major role in the decline of M. sieversii populations, by degrading vegetative parts such as the fine root systems. [27] [28] This immune vulnerability makes M. sieversii become susceptible to more parasites, such as pathogenic insects Agrilus mali, to further destroy the population. [27] [29]
Ex situ conservation, 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 the Kyrgyz Republic. [7] [20] In situ conservation was also found with barbed wire fences being placed around regions distributed with M. sieversii, as seen in areas within Xinyuan, China. [7] A study in 2016 has shown the effectiveness of protecting M. sieversii populations in situ through stratification and seed coat removal. [7] Also, in situ enclosures are more effective in higher elevations as they are at less risk of human and insect injuries. [7]
Aside from traditional conservation methods, biofertilizer has shown effective results inhibiting fungal pathogen, Alternaria alternata 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. [28] Recently, a combination of innovative methods including cloning and plant hormone treatment has also shown effective results in regenerating wild apple populations. [29]
Wild apple trees were heavily lumbered for economical and agricultural uses in the mountains of Kazakhstan during the 1800s. [5] Wild apple forests were turned into pastureland, which greatly changed the soil covering, and damaged young seedlings and roots. [5] Prickly shrubs, such as eglantine and barberry exhibiting symbiotic relationships with wild apples by shielding them from predators were also cut. [5] This further worsened the growing condition for wild apples, and severely weakened root suckers and therefore vegetative propagation. [5]
The peach is a deciduous tree first domesticated and cultivated in Zhejiang province of Eastern China. It bears edible juicy fruits with various characteristics, most called peaches and others, nectarines.
The cucumber is a widely-cultivated creeping vine plant in the family Cucurbitaceae that bears cylindrical to spherical fruits, which are used as culinary vegetables. Considered an annual plant, there are three main types of cucumber—slicing, pickling, and seedless—within which several cultivars have been created. The cucumber originates in Asia extending from India, Nepal, Bangladesh, China, and Northern Thailand, but now grows on most continents, and many different types of cucumber are grown commercially and traded on the global market. In North America, the term wild cucumber refers to plants in the genera Echinocystis and Marah, though the two are not closely related.
Morus, a genus of flowering plants in the family Moraceae, consists of diverse species of deciduous trees commonly known as mulberries, growing wild and under cultivation in many temperate world regions. Generally, the genus has 64 subordinate taxa, three of which are well-known and are ostensibly named for the fruit color of the best-known cultivar: white, red, and black mulberry, with numerous cultivars and some taxa currently unchecked and awaiting taxonomic scrutiny. M. alba is native to South Asia, but is widely distributed across Europe, Southern Africa, South America, and North America. M. alba is also the species most preferred by the silkworm, and is regarded as an invasive species in Brazil and the United States.
Malus is a genus of about 32–57 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples and wild apples.
Mangosteen, also known as the purple mangosteen, is a tropical evergreen tree with edible fruit native to Island Southeast Asia, from the Malay Peninsula to Borneo. It has been cultivated extensively in tropical Asia since ancient times. It is grown mainly in Southeast Asia, southwest India and other tropical areas such as Colombia, Puerto Rico and Florida, where the tree has been introduced. The tree grows from 6 to 25 m tall.
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 most commonly associated with the infection of Malus trees, including species of flowering crabapple, as well as cultivated apple. The first symptoms of this disease are found in the foliage, blossoms, and developing fruits of affected trees, which develop dark, irregularly-shaped lesions upon infection. Although apple scab rarely kills its host, infection typically leads to fruit deformation and premature leaf and fruit drop, which enhance the susceptibility of the host plant to abiotic stress and secondary infection. The reduction of fruit quality and yield may result in crop losses of up to 70%, posing a significant threat to the profitability of apple producers. To reduce scab-related yield losses, growers often combine preventive practices, including sanitation and resistance breeding, with reactive measures, such as targeted fungicide or biocontrol treatments, to prevent the incidence and spread of apple scab in their crops.
The garden strawberry is a widely grown hybrid species of the genus Fragaria in the rose family, Rosaceae, collectively known as the strawberries, which are cultivated worldwide for their fruit. The fruit is widely appreciated for its characteristic aroma, bright red color, juicy texture, and sweetness. It is consumed in large quantities, either fresh or in such prepared foods as jam, juice, pies, ice cream, milkshakes, and chocolates. Artificial strawberry flavorings and aromas are also widely used in products such as candy, soap, lip gloss, perfume, and many others.
Malus sylvestris, the European crab apple, also known as the European wild apple or simply the crab apple, is a species of the genus Malus, native to Europe and western Asia. Its scientific name means "forest apple".
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 named a chemical compound that gives flowers a blue color, Anthokyan, in his treatise "Die Farben der Blüthen". Food plants rich in anthocyanins include the blueberry, raspberry, black rice, and black soybean, among many others that are red, blue, purple, or black. Some of the colors of autumn leaves are derived from anthocyanins.
An apple is a round, edible fruit produced by an apple tree. 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, Malus sieversii, is still found. Apples have been grown for thousands of years in Eurasia and were introduced to North America by European colonists. Apples have religious and mythological significance in many cultures, including Norse, Greek, and European Christian tradition.
A crop wild relative (CWR) is a wild plant closely related to a domesticated plant. It may be a wild ancestor of the domesticated (cultivated) plant or another closely related taxon.
Malus baccata is an Asian species of apple known by the common names Siberian crab apple, Siberian crab, Manchurian crab apple and Chinese crab apple. It is native to many parts of Asia, but is also grown elsewhere as an ornamental tree and for rootstock. It is used for bonsai. It bears plentiful, fragrant, white flowers and edible red to yellow fruit of about 1 cm diameter.
The fig is the edible fruit of Ficus carica, a species of small tree in the flowering plant family Moraceae, native to the Mediterranean region, together with western and southern Asia. It has been cultivated since ancient times and is now widely grown throughout the world. Ficus carica is the type species of the genus Ficus, containing over 800 tropical and subtropical plant species.
Malus niedzwetzkyana, or Niedzwetzky's apple, is a kind of apple native to certain parts of China, Afghanistan, Kazakhstan, Kyrgyzstan, and Uzbekistan noted for its red-fleshed, red-skinned fruit and red flowers. Some botanists consider it a distinct species, while others have argued it is simply an unusual variety of the common apple, Malus pumila.
'Surprise' is a pink-fleshed apple that is the ancestor of many of the present-day pink/red-fleshed apples bred by American growers.
Applecrabs are various hybrids between crabapples and apples. They are bred for varying reasons, including disease resistance and use in cold climates because they are often hardier than apple trees and their fruit has the good eating qualities of apples.
Flamenco, also known as Ballerina Obelisk, is a cultivar of domesticated apple that bears apples good for eating fresh, and is grown for its unusual ornamental properties. The tree grows in a straight up columnar style, with many small fruit-bearing branches. 'Flamenco' is one of a series of apple tree cultivars that share a registered trademark under the name Ballerina.
In 2010, an Italian-led consortium announced they had sequenced the first complete genome of an apple in collaboration with horticultural genomicists at Washington State University, using 'Golden Delicious'. The apple genome has approximately 57,000 genes, which was the highest number of any plant genome studied at the time, and more genes than the human genome which has about 25,000 genes. The modern apple has 17 chromosomes which were found to be derived from an ancestor with 9 chromosomes that experienced genome-wide duplication. The genome sequence also provided proof that Malus sieversii was the wild ancestor of the domestic apple—an issue that had been long-debated in the scientific community. In 2016 a new and much higher quality whole genome sequence (WGS) for a double-haploid derivative of the Golden Delicious variety of apple was published. This new understanding of the apple genome will help scientists identify genes and gene variants that contribute to resistance to disease and drought and other desirable characteristics. Understanding the genes behind these characteristics will help scientists perform more knowledgeable selective breeding.
Malus orientalis, the eastern crabapple or Caucasus apple, is a species in the genus Malus found in Bulgaria, Turkey, the Transcaucasus, and Iran. With its relatively large yellow fruit, it has been consumed by people for millennia, with a string of halved, dried fruit being found in a royal tomb at Ur. Drying the fruit and then rehydrating by boiling cuts the tartness. M. orientalis contributed slightly to the gene pool of domesticated apples, a distant second to Malus sieversii.
Awais Khan is a Pakistani-American plant geneticist and an associate professor at the College of Agriculture and Life Sciences, Cornell University.
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: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)Phylogenetic reconstruction of Pyreae and the genus Malus, relative to major Rosaceae taxa, identified the progenitor of the cultivated apple as M. sieversii