Bananas– The war on wilt, Origin of edibility

Bananas– The war on wilt, Origin of edibility; Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
At the origin of edible bananas are wild species that typically produce fruits full of seeds.
Even though only a handful of species have been domesticated, the banana's wild relatives comprise more than 75 species that are native to the humid tropical forests that extend from India to the Pacific.
We now know that edibility in the bananas and plantains depends primarily on the occurrence of parthenocarpy, which is the development of the fruit without pollination of the female flower (Perrier, 2009, 2011)
and always coupled with more or less female sterility, causing a tendency for the fruit to be seedless (Dodds, 1943).
The potential to produce parthenocarpic fruits has been traced to genes present in Musa acuminata (Simmonds, 1953).
But since these plants were still fertile, they continued mating with other fertile banana plants.
Domestication for edibility most likely started with farmers transplanting the offshoots (suckers) of plants that were edible by virtue of having less seeds and more pulp.
latter could be plants from the same or different (sub)species.
Sterility is most likely due to a combination of structural and genetic factors (Sardos et al. 2016).
The structural factors are linked to hybridization between distant relatives as inherited mismatched chromosomes made it difficult for the progeny to produce fertile ovules and pollen.
But scientists also believe that farmers preferentially propagating the plants that produced fruits with the least seeds might have selected for genes that contribute to sterility (Sardos et al., 2016).
Triploidy made further sexual reproduction extremely unlikely.
Although sterility and parthenocarpy are important factors that contribute to the desirability of banana fruits, sterility has impeded progress in breeding programs.
Through natural somatic (vegetative) mutation, hybridization, and selection over many thousands of years, considerable genetic variability has arisen within the cultivated bananas, giving rise to more than 1000 varieties (Nelson, 2002).
Figure 2. Evolution of the cultivated bananas, modified from Simmonds (1995) by Nayar (2010)

Bananas– The war on wilt, The Genus Musa

Bananas– The war on wilt, The Genus Musa ; Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
The genus Musa was initially divided in two species: M. paradisiaca for plantains and M. sapientum for the common banana by Linnaeus, respectively.
However, it was soon discovered that both were falsely identified as separate species and in fact both were hybridized variants of M. paradisiaca and M. balbisiana.
Eventually, M. x paradisiaca was accepted as the general name for the hybrid species (Valmayor et al., 2000)
At the moment the genus comprises four different sections, with each their own characteristics.
Two with 11 chromosome pairs and two with 10 chromosome pairs.
Two with 11 chromosome pairs and two with 10 chromosome pairs. Section Eumusa Baker may be called the group of the true bananas.
It contains the two commonest and most widely ranging species in the genus, M. acuminata and M. balbisiana and with them all the cultivated forms that we believe to have been derived from them.
Bananas and plantains are starchy berries produced by hybrids and/or sports of Musa acuminata and Musa balbisiana.
Rare genome contributions from another species may have occurred but are not yet well documented (Simmonds, 1986).
M. balbisiana combines with almost anything, which is very interesting in view of its wide range, well-defined nature as a species, and relatively narrow variation (Cheesman, 1947).
Musa balbisiana accessions displayed resistance to Xanthomonas wilt in a greenhouse trial (Tripathi et al., 2008).
Musa acuminata is a wild species of banana best known for being at the origin of the vast majority of edible bananas, by itself or through hybridization with Musa balbisiana.
Four subspecies (banksii, zebrina, malaccensis and burmannica) have been confirmed to be involved in the domestication of the banana (Perrier, 2009).

Bananas– The war on wilt, Taxonomy

Bananas– The war on wilt, Taxonomy  ;Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
Bananas belong to the genus Musa of the Musaceae in the order Zingiberales (Stover and Simmonds, 1987).
Musaceae includes 2 genera, Ensete and Musa.
The family has not been revised after the classical work of Cheesman (1947–1950) and Simmonds (1953, 1962), although several species have been subsequently described (Nayar, 2010).

Bananas– The war on wilt, Morphology

Bananas– The war on wilt, Morphology ;Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
Bananas are the very variable fruits derived from crossed species within the genus Musa, therefore a general morphological description of the genus Musa is included.
The banana plant is a large, perennial, monocarpic (fruiting once, then dying), monocotyledonous herb 2-9 m in height that arises from large, subterranean rhizomes (Nelson et al., 2006). The roots are adventitious,
spreading 4-5 m laterally, descending to 75 cm, but mainly in the top 15 cm,
forming a dense mat (Moore, 1992). Suckers spring up around the main plant forming a clump or "stool'', the eldest sucker replacing the main plant when it fruits and dies, and this process of succession continues indefinitely (Morton, 1987).
Leaves are produced by a single apical meristem, which typically forms only a low short stem or pseudobulb (McClatchey, 2000).
Smooth, oblong or elliptic, fleshy-stalked leaves, numbering 4 or 5 to 15, are arranged spirally. They may be entirely green, green with maroon splotches, or green on the upper side and red purple beneath (Morton 1987).
The petioles of the leaves are long and expanded below into long, sheathing and stem-encircling leaf-bases forming a pseudostem (Cheesman, 1947).
New leaves originating from the corm grow up continuously through the centre of the pseudostem with their laminas tightly rolled.
The emerging leaf unfolds a large oblong blade, 150-400 cm x 70-100 cm, with a pronounced supporting midrib and well-marked, pinnately arranged, parallel veins (Moore, 1992).
One terminal inflorescence rises from each corm, its axis (peduncle) extending through the centre of the pseudostem and bending down when exserted (Moore, 1992).
The spike, at first, is a large, long-oval, tapering, purple-clad bud.
As it opens, it is seen that the slim, nectar-rich, tubular, toothed, white flowers are clustered in whorled double rows along the floral stalk, each cluster covered by a thick, waxy bract, purple outside, deep-red within.
Normally, the bract will lift from the first hand in 3 to 10 days. If the plant is weak, opening may not occur until 10 or 15 days (Morton, 1987).
The bracts open in sequence (about 1 per day) from base to top while the peduncle elongates.
They often become reflexed when the flowers develop and they are shed when the fruits start to develop, but this differs between species.
Female flowers develop in the proximal 5-15 rows, male flowers at the distal end of the inflorescence, in the middle sometimes neuter flowers are present (Moore, Figure 1. Basic morphology of the banana plant 1992).
The flowers contain 5 stamens and an inferior, trilocular ovary.
The perianth (according to the usual interpretation) usually consists of two parts: a compound tepal (calyx) essentially tubular, but split to the base on the adaxial side, 5-toothed at the apex (Cheesman, 1947).
In about one day after the opening of the flower clusters, the male flowers and their bracts are usually shed,
leaving most of the upper stalk naked except at the very tip where there usually remains an unopened bud containing the last-formed of the male flowers.
However, there are some mutants such as 'Dwarf Cavendish' with persistent male flowers and bracts which wither and remain, filling the space between the fruits and the terminal bud (Morton, 1987).
The fruits are variable in size, shape and colour. They are generally elongate-cylindrical, straight to strongly curved, 3-40 cm long and 2-8 cm in diameter.
The fruit apex is important in variety identification; it may be tapered, rounded or blunt (Nelson, 2002).
The endocarp, ivory-white to yellow or pink, may be firm, even gummy with latex when unripe, turning tender and slippery, or soft and mellow or rather dry and mealy or starchy when ripe.
The flavour may be mild and sweet or subacid with a distinct apple tone.
The common cultivated types are generally seedless with only vestiges of ovules visible as brown specks (Morton, 1987).
Seeds are often present in wild Musa species.
When seeds are present, they vary among species in shape and morphology.
Seeds of Musa balbisiana are dark brown, ovoid, about 4 mm long with a conspicuous white, powdery endosperm (Nelson, 2002).

Bananas– The war on wilt, Chemistry of bananas

Bananas– The war on wilt, Chemistry of bananas   ;Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
Bananas, mainly consisting of carbohydrates (22.2 to 31.2 percent), are low in fats, cholesterol, and sodium.
They are extremeley high in potassium (400 miligrams to 100 grams of pulp), which helps normalize the heartbeat, sends oxygen to the brain and regulates the
body’s water-balance (Girish and Satish, 2008) and therefore makes bananas the perfect food to help beat high blood pressure (Debabandya et al., 2010).
Bananas are a good source of vitamin C (Stover and Simmonds, 1987) and vitamin B, which helps calm the nervous system (Singh and Bhat, 2003).
During ripening, the starch component is gradually converted to simple sugars (fructose, glucose, and sucrose), while the moisture content of the pulp increases.
The time of conversion to simple sugars can also be used to differentiate plantains from bananas, which are consumed raw.
Namely, plantains or cooking bananas converse later compared to raw bananas (McClatchey, 2000).
A study by Ashraf et al. (2010) proved that ripe bananas exhibit fluorescence when exposed to ultraviolet light,
suggesting that this allows animals which are able to see light in the ultraviolet spectrum, can more easily detect ripened bananas.
All parts of the banana plant have medicinal applications (Amit and Shailandra, 2006).
Antifungal and antibiotic principles are found in the peel and pulp of fully ripe bananas (Brooks, 2008).
A fungicide in the peel and pulp of green fruits is active against a fungus disease of tomato plants (Ponnuswamy et al., 2011).
Norepinephrine, dopamine, and serotonin are also present in the ripe peel and pulp (Ratule et al., 2007).
The first two elevate blood pressure; serotonin inhibits gastric secretion and stimulates the smooth muscle of the intestines (Anhwang et al., 2009).
Bananas can also help people trying to give up smoking,
as the high levels of Vitamin C, A1, B6, B12 they contain, as well as the potassium and magnesium found in them, help the body recover from the effects of nicotine withdrawal (Mokbel and Hashinaga, 2005)
potassium and magnesium found in them, help the body recover from the effects of nicotine withdrawal (Mokbel and Hashinaga, 2005)

Bananas– The war on wilt, Bananas in human culture

Bananas– The war on wilt, Bananas in human culture, Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
Bananas have played a significant role in culture and religion.
Banana plants are often used in cuisine, as packaging material, and as religious offerings, for instance.
Additionally, countless references have been made to bananas in pop culture, particularly in music, graphic art, video games, and film and television.
Here, a small selection from a wide range of banana-related religious and cultural practices will be touched upon.
In addition to the consumption of the banana fruits, banana leaves are also often utilized in cuisine.
When banana leaves are used in cuisine, the leaves are in fact not consumed, but rather used as packaging material.
For instance, the Indonesian snack ‘lemper’, which is a roll made of sticky rice and seasoned meat filling, is often packaged in banana leaves.
Additionally, banana leaves are often used in religious and cultural practices.
This occurs predominantly in Buddhism and Hinduism, where banana leaves are used as material to produce offering bowls with or as decoration.
Additionally, in Hinduism banana trees are sacred and considered to be a symbol of fertility, and the leaves are often used in offerings (Lim, 2012).
Interestingly, in addition to Hinduism and Buddhism, cultural uses of bananas have been observed.
For instance, early Hawaiians have used banana suckers as truce flags in times of war (Lim, 2012).
In modern pop culture, bananas are often referred to.
For instance, in 1923, Frank Silver and Irving Cohn composed a song named ‘Yes! We have no bananas’, which became a major hit soon after its release.
The song has been referred to multiple times afterwards, often in context of a banana-related catastrophe.
For instance, New York Times author Dan Koeppel wrote an article about the Cavendish banana and funghal diseases, named ‘Yes, we will have no bananas’ (Koeppel, 2008).
Additionally, in comedic film and television, people are often shown slipping on banana peels.
This gag runs back to at least the early 20th century and is still often used nowadays, even outside of comical film and television (Garrison, 2012).
For instance, in the popular Nintendo videogame ‘Mario Kart’, banana peels are used to make opponents slip and as such, the player gains an advantage over his/her opponents.
Interestingly, the 2014 Ig Nobel Prize, which is awarded to research that is in some way remarkable or comical, was given to researches which clarified the mechanisms behind the slippery nature of banana peels.

Bananas– The war on wilt, Bananas in human culture, Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
Bananas have played a significant role in culture and religion.
Banana plants are often used in cuisine, as packaging material, and as religious offerings, for instance.
Additionally, countless references have been made to bananas in pop culture, particularly in music, graphic art, video games, and film and television.
Here, a small selection from a wide range of banana-related religious and cultural practices will be touched upon.
In addition to the consumption of the banana fruits, banana leaves are also often utilized in cuisine.
When banana leaves are used in cuisine, the leaves are in fact not consumed, but rather used as packaging material.
For instance, the Indonesian snack ‘lemper’, which is a roll made of sticky rice and seasoned meat filling, is often packaged in banana leaves.
Additionally, banana leaves are often used in religious and cultural practices.
This occurs predominantly in Buddhism and Hinduism, where banana leaves are used as material to produce offering bowls with or as decoration.
Additionally, in Hinduism banana trees are sacred and considered to be a symbol of fertility, and the leaves are often used in offerings (Lim, 2012).
Interestingly, in addition to Hinduism and Buddhism, cultural uses of bananas have been observed.
For instance, early Hawaiians have used banana suckers as truce flags in times of war (Lim, 2012).
In modern pop culture, bananas are often referred to.
For instance, in 1923, Frank Silver and Irving Cohn composed a song named ‘Yes! We have no bananas’, which became a major hit soon after its release.
The song has been referred to multiple times afterwards, often in context of a banana-related catastrophe.
For instance, New York Times author Dan Koeppel wrote an article about the Cavendish banana and funghal diseases, named ‘Yes, we will have no bananas’ (Koeppel, 2008).
Additionally, in comedic film and television, people are often shown slipping on banana peels.
This gag runs back to at least the early 20th century and is still often used nowadays, even outside of comical film and television (Garrison, 2012).
For instance, in the popular Nintendo videogame ‘Mario Kart’, banana peels are used to make opponents slip and as such, the player gains an advantage over his/her opponents.
Interestingly, the 2014 Ig Nobel Prize, which is awarded to research that is in some way remarkable or comical, was given to researches which clarified the mechanisms behind the slippery nature of banana peels.

Bananas– The war on wilt, :Bananas and humans

Bananas– The war on wilt, Bananas and humans Bananas– The war on wilt ;Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
Bananas are very healthy, eating bananas as part of a regular diet can cut the risk of death by strokes by as much as 40% (Amit and Shailandra, 2006).
In 2004, the global production of bananas was 106 million tonnes, which made it the second most important fruit crop of the world, only after citrus (FAOSTAT, 2004).
The top banana-producing countries of the world are India (15% of total production), China, Ecuador, Brazil and Philippines (FAO, 2003).
Bananas provides 10 to 27% of the daily calorie intake of the population in several countries and helps provide year-round food security (Nayar, 2010).
In 2011 bananas were the world’s fifth most important food crops after maize, rice, wheat and cassava (Tripathi, 2011).
Nelson et al. (2006) stated that the plant genus Musa is of extraordinary significance to human societies due to its fruit bananas.
Musa species grow in a wide range of environments and have varied human uses, ranging from the edible bananas of the tropics to fibre and ornamental plants, although often named differently in many cultures.
Musa species attained a portion of central importance within Pacific societies:
the plant is a source of food, beverages, fermentable sugars, medicines, flavourings, cooked foods, fragrance, rope, shelter, clothing and numerous ceremonial and religious uses (Nelson et al., 2006).
Bananas are the second best sold tropical fruit in The Netherlands (GFK, 2014).
Dutch people eat about 720 million bananas a year, mostly from the cultivar ‘Giant Cavendish’, also known as the dessert banana, which can be eaten raw.
Though, in many tropical countries they prefer bananas that have to be baked before they can be eaten, so called plantains.
Bananas may be differentiated from plantains on the basis of moisture content, with bananas generally averaging 83 percent moisture and plantains 65 percent, but intermediate examples may also be found (Lessard, 1992).

Bananas– The war on wilt, Introduction

Bananas– The war on wilt, Introduction,Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rureng
Recent headlines have been stating the global banana production is under great threat.
‘Why bananas as we know them might go extinct (again)’ - CNN.
‘Bananas face extinction due to spread of unstoppable deadly fungus’ – Express, UK.
'World’s top banana could go extinct’ – Wall Street Journal.
What is the actual current state on bananas as we know them?
This study provides an insight in the threats concerning global banana production, current control measures and recommendations for future pest control.

Bananas– The war on wilt, Abstract

Bananas– The war on wilt, Abstract ,Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga
This literature study provides an insight into the threats concerning global banana production, current control measures and recommendations for future pest control.
First, the cultural and economic value of bananas is discussed.
Banana morphology, taxonomy, distribution and ecology is explored and four major threats to the banana are exposed. Finally, the current control methods for these threats are examined.
Finally, the current control methods for these threats are examined.
Recent headlines have been stating the global banana production is under great threat.
‘Why bananas as we know them might go extinct (again)’ - CNN.
‘Bananas face extinction due to spread of unstoppable deadly fungus’ – Express, UK.
'World’s top banana could go extinct’ – Wall Street Journal.
What is the actual current state on bananas as we know them?
This study provides an insight in the threats concerning global banana production, current control measures and recommendations for future pest control.

Bananas– The war on wilt, Rody Blom, Saskia Bollerman, Janna Horjus, Koen Rurenga

Bananas– The war on wilt

chapter
2018.B.01:Abstract
2018.B.02:Introduction
2018.B.03:Bananas and humans
2018.B.04:Bananas in human culture