Musa (genus)

Musa is one of two or three genera in the family Musaceae. The genus includes flowering plants producing edible bananas and plantains. Around 70 species of Musa are known, with a broad variety of uses.

Musa
Starr 050826-4195 Musa sp..jpg
Banana plants, Kanaha Beach, Maui
Scientific classification e
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Zingiberales
Family: Musaceae
Genus: Musa
L.[1]
Species

Around 70, see text.

Though they grow as high as trees, banana and plantain plants are not woody and their apparent "stem" is made up of the bases of the huge leaf stalks. Thus, they are technically gigantic herbs.

Musa species are used as food plants by the larvae of some Lepidoptera species, including the giant leopard moth and other Hypercompe species, including H. albescens (only recorded on Musa), H. eridanus, and H. icasia.

DescriptionEdit

Banana plants represent some of the largest herbaceous plants existing in the present, with some reaching up to 9 metres (30 ft) in height. The large herb is composed of a modified underground stem (rhizome), a false trunk, a network of roots, and a large flower spike. The false trunk is an aggregation of the basal portion of leaf sheathes; it is not until the plant is ready to flower that a true stem grows up through the sheath and droops back down towards the ground.[2] At the end of this stem grows a peduncle with many female flowers protected by large purple-red bracts. The extension of the stem (this part called the rachis) continues growth downward where a terminal male flower grows. The leaves originate from a pseudostem and unroll to show a leaf blade with two lamina halves.[3] Musa reproduces by both sexual (seed) and asexual (suckers) processes, utilizing asexual means when producing sterile (non-seedy) fruits. Further qualities to distinguish Musa include spirally arranged leaves, fruits as berries, latex-producing cells present, 5 connate and 1 member of the inner whorl distinct, and petiole with one row of air channels.[4]

Systematics and taxonomyEdit

HistoryEdit

The genus Musa was first named by Carl Linnaeus in 1753.[5] The name is a Latinization of the Arabic name for the fruit, mauz (موز). Mauz meaning Musa is discussed in the 11th-century Arabic encyclopedia The Canon of Medicine, which was translated to Latin in medieval times and well known in Europe.[Note 1] Muz is also the Turkish, Persian, and Somali name for the fruit. Some sources assert that Musa is named for Antonius Musa, physician to the Emperor Augustus.[6] The word "banana" came to English from Spanish and Portuguese, which in turn apparently obtained it from a West African language (possibly Wolof).[7]

From the time of Linnaeus until the 1940s, different types of edible bananas and plantains were given Linnaean binomial names, such as Musa cavendishii, as if they were species. In fact, edible bananas have an extremely complicated origin involving hybridization, mutation, and finally selection by humans. Most edible bananas are seedless (parthenocarpic), hence sterile, so they are propagated vegetatively. The giving of species names to what are actually very complex, largely asexual, hybrids (mostly of two species of wild bananas, Musa acuminata and Musa balbisiana) led to endless confusion in banana botany. In the 1940s and 1950s, it became clear to botanists that the cultivated bananas and plantains could not usefully be assigned Linnean binomials, but were better given cultivar names.[citation needed]

 
Food served on a banana leaf, a traditional way of serving food more popular in southern India

SectionsEdit

Musa sectional systematics possesses a history dating back to 1887. In that year, M.P. Sagot published “Sur Le Genre Bananier”, where the genus Musa was first formally classified.[8] In this article, Sagot grouped the Musa species into three groups, although no section names were assigned to them. The grouping was based on morphological traits, establishing the trio as:

  1. Bananas with fleshy fruit;
  2. Ornamental bananas with upright inflorescences and bracts that were vibrantly colored; and
  3. Bananas that were giant in size.

In 1893, five years after Sagot's article, J.G. Baker made the first formal designation of Musa sections. To do so, he named three subgenera which almost paralleled the sections that had been described by Sagot.[9] These sections were:

  1. M. subg. Physocaulis Baker: a group defined by a bract with many flowers, inedible fruits, and a bottle-shaped stem.
  2. M. subg. Rhodochlamys Baker: brightly-colored bracts with few flowers, usually inedible fruits, and cylindrical stems.
  3. M. subg. Eumusa Baker which possessed green, brown, or dull-violet bracts with many flowers, usually edible fruits, and cylindrical stems.

After this classification, 50 years passed without revision to the banana sections. In 1947, Cheeseman reclassified the taxon based on morphological features and chromosome number.[10] This project proposed 4 sections:

  1. M. sect. Eumusa Cheesman (2n = 2x = 22)
  2. M. sect. Rhodochlamys (Baker) Cheesman (2n = 2x = 22)
  3. M. sect. Australimusa Cheesman (2n = 2x = 20)
  4. M. sect. Callimusa Cheesman (2n = 2x = 20)

The addition of another Musa section came in 1976 in G.C.G. Ardent's "The wild bananas of Papua New Guinea". The added section, M. sect. Ingentimusa Ardent, was based on a single species, Musa ingens.[11] This designation put the number of sections in Musa at five: Eumusa, Rhodochlamys, Callimusa, Australimusa, and Ingentimusa .

In the 21st century, genomics have become cheaper, more efficient, and more accurate, and Musa genetic research has increased exponentially. Research was conducted around a diversity of genomic markers (cpDNA, nrDNA, rDNA, introns, various spacers, etc.). The results of many of these studies suggested that the five sections of Musa defined by morphology (and listed above) were not monophyletic.[12][13]

Based on the incorrect section grouping, Markku Häkkinen proposed another reclassification of the Musa sections in 2013. Using a multitude of genetic evidence and markers from other studies, Häkkinen suggested the reduction of five Musa sections into two: Musa and Callimusa.[13] Unlike sectional classifications of the past, this hypothesis was based on genetic markers rather than morphological features or chromosome number. The two groups were generally formed by the clustering of the previously defined groups:

  • Musa sect. Rhotochlamys and M. sect. Eumusa  became M. sect. Musa
  • M. sect. Ingetimusa, M. sect. Callimusa and M. sect. Australimusa  became M. sect. Callimusa

The advance of genomic analysis technologies and further data on the relatedness of Musa species, formulated Häkkinen's two sections and later corroborated them as correct subcategories for the genus.[14][15][16] The history of Musa sections provides an example of genomics superseding morphological evidence and thus classifications.

SpeciesEdit

The World Checklist of Selected Plant Families accepts 68 species and two primary hybrids, as of January 2013, which are listed below.[17] The assignment to sections is based on GRIN (where this gives the species),[18] regrouped according to Wong et al.[19]

Section Callimusa (incorporating Australimusa)Edit

 
Fruit stalk of Musa sp.
 
Banana flowers

[A] and [C] indicate known placement in the former sections Australimusa and Callimusa, respectively.[20]

Section IngentimusaEdit

Section Musa (incorporating Rhodochlamys)Edit

 
Musa acuminata with inflorescence
 
Japanese fiber banana (Musa basjoo) flowering at Cotswold Wildlife Park
 
Musa ornata 'Roxburgh' in China
 
Pink banana (Musa velutina) flower

Section undetermined or unknownEdit

 
Varigated form of Musa sp.
 
Musa sp.

Formerly placed hereEdit

Cultivated bananasEdit

A number of distinct groups of plants bearing edible fruit have been developed from species of Musa. In English, fruits which are sweet and used for dessert are usually called "bananas", whereas starchier varieties used for cooking are called "plantains", but these terms do not have any botanical significance. By far the largest and now the most widely distributed group of cultivated bananas is derived from section Musa, particularly M. acuminata and M. balbisiana, either alone or in various hybrid combinations. The next but much smaller group is derived from members of section Callimusa (previously classified as Australimusa) and is restricted in importance to Polynesia. Of even more restricted importance are small groups of hybrids from Papua New Guinea; a group from section Musa to which Musa schizocarpa has also contributed, and a group of hybrids between section Musa and section Callimusa.[citation needed]

Banana and plantains are the fourth most produced food globally surpassed only by the staple crops of rice, wheat and maize.

PropertiesEdit

Plants of the Musa spp. including roots, flowers and fruits have been used in the folk medicine cultures of Africa, Asia, India and the Americas. Modern studies examining the properties of the fruits have found diversity of bioactive compounds among genotypes compared with commercially grown cultivars.[22]

Section Musa cultivarsEdit

When the Linnaean binomial system was abandoned for cultivated bananas, an alternate genome-based system for the nomenclature of edible bananas in section Musa was devised. Thus, the plant previously known by the "species" name Musa cavendishii became Musa (AAA Group) 'Dwarf Cavendish'. The "new" name shows clearly that 'Dwarf Cavendish' is a triploid, with three sets of chromosomes, all derived from Musa acuminata, which is designated by the letter "A". When Musa balbisiana is involved, the letter "B" is used to denote its genome. Thus, the cultivar 'Rajapuri' may be called Musa (AAB Group) 'Rajapuri'. 'Rajapuri' is also a triploid, expected to have two sets of chromosomes from Musa acuminata and one from Musa balbisiana. In the genome of edible bananas from section Musa, combinations such as AA, BB, ABB, BBB and even AAAB can be found.

For a more detailed explanation of this system and a list of some edible banana and plantain cultivars using it, see the List of banana cultivars.

Fe'i-type cultivarsEdit

No such nomenclature system has been developed for the group of edible bananas derived from section Callimusa. This group is known generally as the "Fe'i" or "Fehi" bananas, and numerous cultivars are found in the South Pacific region. They are very distinctive plants with upright fruit bunches, featuring in three of Paul Gauguin's paintings. The flesh can be cooked before eating and is bright orange, with a high level of beta carotene. Fe'i bananas are no longer very important for food, as imported foods have grown in popularity, although some have ritual significance. Investigations are under way to use the Fe'i karat bananas (the name derives from "carrot" due to the intense orange-yellow color of the fruit) in prevention of childhood blindness in Pohnpei.[23] Fe'i bananas probably derive mainly from Musa maclayi, although their origins are not as well understood as the section Musa bananas. Cultivars can be formally named, as e.g. Musa (Fe'i Group) 'Utafun'.

See alsoEdit

NotesEdit

  1. ^ Arabic Mauz meaning Musa or banana is in the medieval Arabic medical encyclopedia by Avicenna, which is online at Avicenna: Book Two. See also "Musa" at Dictionary.Reference.com. See also Musacées in Dictionnaire Étymologique Des Mots Français D'Origine Orientale, by L. Marcel Devic (year 1876).
  2. ^ Musa beccarii is reported as having a haploid chromosome number of 9 or 10, the latter due to multivalent formation during meiosis. Although genetically it nestles comfortably within section Callimusa the chromosome number needs clarification.[citation needed]
  3. ^ Musa basjoo is the most cold hardy species of Musa, growing and fruiting successfully in outdoor cultivation in the British Isles and British Columbia.[citation needed]

ReferencesEdit

  1. ^ GRIN (2009-02-19). "Genus: Musa L." Taxonomy for Plants. National Germplasm Resources Laboratory, Beltsville, Maryland: USDA, ARS, National Genetic Resources Program. Archived from the original on 2012-10-11. Retrieved 2011-02-06.
  2. ^ The Editors of Encyclopaedia Britannica. “Banana.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 22 Aug. 2019, www.britannica.com/plant/banana-plant.
  3. ^ Rouard, Mathieu, et al. “Morphology of Banana Plant.” The Banana Knowledge Platform of the ProMusa Network, Feb. 2019, www.promusa.org/Morphology+of+banana+plant.
  4. ^ Judd, Walter S. Plant Systematics a Phylogenetic Approach. Sinauer Assoc., 2007.
  5. ^ "Musa". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew. Retrieved 2013-01-10.
  6. ^ Bailey, Liberty Hyde (1914–1917). The Standard Cyclopedia of Horticulture. Vol. 4.. New York: Macmillan. OCLC 2768915.. Pp. 2076–9.
  7. ^ "Banana" at Dictionary.Reference.com.
  8. ^ Sagot, M. P. “Sur Le Genre Bananier.” Bulletin De La Société Botanique De France, vol. 34, no. 7, 1887, pp. 328–330., doi:10.1080/00378941.1887.10830263.
  9. ^ Baker, J.G. 1893. A synopsis of the genera and species of Museae. Ann. Bot. (Oxford) 7: 189–229.
  10. ^ Cheesman, E.E. 1947 [pub. 1948]. Classification of the bananas. II. The genus Musa L. Kew Bull. 2: 106–117. http://dx.doi.org/10.2307/4109207
  11. ^ Argent, G.C.G. 1976. The wild bananas of Papua New Guinea. Notes Roy. Bot. Gard. Edinburgh 35: 77–114.
  12. ^ Wong C, Kiew R, Argent GCG, Set O, Lee SK, Gan YY. Assessment of the validity of the sections in Musa (Musaceae) using AFLP. Ann Bot-London. 2002; 90: 231–238.
  13. ^ a b Häkkinen, Markku. “Reappraisal of Sectional Taxonomy in Musa (Musaceae).” Taxon, vol. 62, no. 4, 2013, pp. 809–813., doi:10.12705/624.3.
  14. ^ Feng, Huimin, et al. “Molecular Phylogeny of Genus Musa Determined by Simple Sequence Repeat Markers.” Plant Genetic Resources, vol. 14, no. 3, 2015, pp. 192–199., doi:10.1017/s1479262115000222.
  15. ^ Lamare, Animos; et al. "Phylogenetic Implications of the Internal Transcribed Spacers of NrDNA and Chloroplast DNA Fragments of Musa in Deciphering the Ambiguities Related to the Sectional Classification of the Genus". Genetic Resources and Crop Evolution. 64 (6): 1241–1251. doi:10.1007/s10722-016-0433-9.
  16. ^ Čížková, J; Hřibová, E; Christelová, P; Van den Houwe, I; Häkkinen, M; et al. (2015). "Molecular and Cytogenetic Characterization of Wild Musa Species". PLOS ONE. 10 (8): e0134096. doi:10.1371/journal.pone.0134096.
  17. ^ Search for "Musa". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew. Retrieved 2013-01-10.
  18. ^ GRIN (2009-02-19). "Species in GRIN for genus Musa". Taxonomy for Plants. National Germplasm Resources Laboratory, Beltsville, Maryland: USDA, ARS, National Genetic Resources Program. Archived from the original on 2012-12-12. Retrieved 2011-02-06.
  19. ^ Wong, C.; Kiew, R.; Argent, G.; Set, O.; Lee, S.K. & Gan, Y.Y. (2002). "Assessment of the Validity of the Sections in Musa (Musaceae) using ALFP". Annals of Botany. 90 (2): 231–238. doi:10.1093/aob/mcf170. PMC 4240415. PMID 12197520.CS1 maint: ref=harv (link)
  20. ^ Office of the Gene Technology Regulator (2008). The Biology of Musa L. (banana) (PDF). Australian Government.
  21. ^ "Ensete lasiocarpum". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew. Retrieved 2013-01-10.
  22. ^ Pearson, Valerie A. (2016). Bananas: Cultivation, Consumption and Crop Diseases. Nova Science Publishers. p. 1. ISBN 978-1-63485-418-4.
  23. ^ Coghlan, Andy (2004-07-10). "Orange banana to boost kids' eyes". New Scientist.

Further readingEdit

External linksEdit