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A boundless curiosity for bananas

Anne Vézina Thursday, 19 November 2020

Finding out at the age of 13 that the banana plant is a giant herb sent Gabriel Sachter-Smith on a quest to learn everything he could about bananas. It began with spending much of high school reading about bananas and getting potted plants to fruit indoors in non-tropical Colorado, USA. His tinkering progressed to breeding experiments that were showcased in science fairs.

After high school, Sachter-Smith studied tropical plant sciences at the University of Hawaii’s CTAHR. During that time, he honed his banana cultivation skills at a student farm he helped set up and, whenever possible, he made bananas the topic of his class assignments to learn more about them.

His name was already circulating within the banana community when he attended the 2009 ISHS-ProMusa symposium in Guangzhou, China, which led to an internship at the International Institute of Tropical Agriculture’s banana breeding program in Uganda the following summer. In addition to breeding techniques, he learned how to characterize and document banana plants. His experience helped him land his first assignment abroad. In 2011, he spent a month in the Solomon Islands to train field collection curators in morphological characterization as part of a project funded by the Crop Trust.

Parcel on which Gabriel Sachter-Smith grows and breeds bananas.
Parcel on which Gabriel Sachter-Smith grows and breeds bananas.

The self-described 'Musologist' went on to do an MSc thesis on the search of naturally occurring resistance to Bunchy top. Since graduating, he has combined exploring banana diversity in Asia and the Pacific, with growing a diversity of banana cultivars on a farm in Oahu’s North Shore, where he took up banana breeding again.

Between 2016 and 2019, Sachter-Smith participated in a series of collecting missions, organized by the Alliance of Bioversity International and CIAT and local hosts*, in Bougainville, Cook Islands, Samoa and Papua New Guinea (PNG). In 2018-19, he also participated in missions organized by CIRAD to look for Musa balbisiana in Vietnam, Laos and China**. These and more are featured in the World Banana Tour presentation he did for this year’s Hawaii Tropical Fruit Growers Conference. His publications, including catalogs of cultivars, are available in Musalit.

The photos below were originally posted on his Instagram account, Hawaii Banana Source, and the captions are from him.

*The SPC, NARI in Bougainville and PNG, the Cook Islands Ministry of Agriculture and the Samoa Ministry of Agriculture and Fisheries.

**The team also included scientists from the Museum national d’Histoire naturelle, the Institute of Tropical Biology, NOMAFSI and the Kunming Institute of Botany.


The man behind me thought it was funny that I wanted to get a wild banana. "Em no gut! I gat pleni seed lo em!" he kept saying in PNG’s Tok Pisin. The bunch I’m holding belongs to the species ((Musa acuminata|''Musa acuminata'')), the main ancestral species present in most edible cultivars, either by itself or with other ''Musa'' species. There are over 20 described forms of ''Musa acuminata'', several of which contributed to edible bananas. This one is ((Musa acuminata ssp. banksii|''Musa acuminata ssp. banksii'')), which in my view is the most interesting one. It’s native to [https://en.wikipedia.org/wiki/New_Guinea|New Guinea] and surrounding islands, where it seems to be still influencing the ((domestication of the banana|domestication of edible bananas)).  We usually talk of domestication as something that happened millennia ago. But I think the door is always open.

The man behind me thought it was funny that I wanted to get a wild banana. "Em no gut! I gat pleni seed lo em!" he kept saying in PNG’s Tok Pisin. The bunch I’m holding belongs to the species Musa acuminata, the main ancestral species present in most edible cultivars, either by itself or with other Musa species. There are over 20 described forms of Musa acuminata, several of which contributed to edible bananas. This one is Musa acuminata ssp. banksii, which in my view is the most interesting one. It’s native to New Guinea and surrounding islands, where it seems to be still influencing the domestication of edible bananas. We usually talk of domestication as something that happened millennia ago. But I think the door is always open.


There is a population of ''banksii'' in Samoa. How it got there from New Guinea is a mystery. We will never know whether it was introduced by humans or animals. Its name in Samoa is 'Fa'i Taemanu', which means bird dropping banana because birds eat it and spread it around. During a [https://www.musalit.org/seeMore.php?id=18963|collecting mission to Samoa], we were lucky to find a parthenocarpic specimen (top right) which is the first step to the domestication of edible bananas. Normally, wild bananas produce seeded fruits only if the ovules in the ((Banana flowers|female flowers)) have been pollinated. But parthenocarpic plants have the ability to form fruits without the stimulus of pollination. This would have been the kind of plant from which people would have collected a ((Banana sucker|sucker)) to transplant in their garden. Being fertile, these plants would cross with other bananas. Over time, crosses combined with selection for seedlessness produced mostly sterile cultivars of various [https://en.wikipedia.org/wiki/Ploidy|ploidy]. Like their wild parents, the first cultivars were diploid (two sets of chromosomes). They tend to have been displaced by the generally more robust and productive triploid cultivars (three sets), which are the main types that were spread outside the banana’s native range. Until recently, the only known tetraploid cultivars (four sets) were the products of forced crossings by breeders, but a few naturally occurring tetraploids have since been documented.

There is a population of banksii in Samoa. How it got there from New Guinea is a mystery. We will never know whether it was introduced by humans or animals. Its name in Samoa is 'Fa'i Taemanu', which means bird dropping banana because birds eat it and spread it around. During a collecting mission to Samoa, we were lucky to find a parthenocarpic specimen (top right) which is the first step to the domestication of edible bananas. Normally, wild bananas produce seeded fruits only if the ovules in the female flowers have been pollinated. But parthenocarpic plants have the ability to form fruits without the stimulus of pollination. This would have been the kind of plant from which people would have collected a sucker to transplant in their garden. Being fertile, these plants would cross with other bananas. Over time, crosses combined with selection for seedlessness produced mostly sterile cultivars of various ploidy. Like their wild parents, the first cultivars were diploid (two sets of chromosomes). They tend to have been displaced by the generally more robust and productive triploid cultivars (three sets), which are the main types that were spread outside the banana’s native range. Until recently, the only known tetraploid cultivars (four sets) were the products of forced crossings by breeders, but a few naturally occurring tetraploids have since been documented.


((Musa balbisiana|''Musa balbisiana'')) is the other wild species whose genetic makeup is found alongside ''Musa acuminata''’s in several edible bananas. It’s often found growing near villages and in people’s gardens, but these cultivated plants are different (see below). It’s quite difficult to find wild populations but it seems we found the real deal in Vietnam.

Musa balbisiana is the other wild species whose genetic makeup is found alongside Musa acuminata’s in several edible bananas. It’s often found growing near villages and in people’s gardens, but these cultivated plants are different (see below). It’s quite difficult to find wild populations but it seems we found the real deal in Vietnam.


''Musa balbisiana'' is widely cultivated for non-fruit uses, such as animal feed. The fiber is also used to make cloth or rope, the thick leaves are used for cooking, and the male bud is eaten. The cultivated plants tend to have larger fruits and more pulp, compared to the wild ones, and the seeds don’t form completely and stay kind of soft. These plants are grown from suckers, which could explain why the seeds are not viable. When I toured Northern Vietnam with French and Vietnamese scientists at the end of 2018, I was surprised to see that nearly every restaurant had wild banana infused alcohol and that in every small town there were bunches of ''Musa balbisiana'' awaiting processing outside herbal shops. The seeds are extracted (and used in ways that are not clear to me) and the fruits are sliced and steeped in alcohol (inset).

Musa balbisiana is widely cultivated for non-fruit uses, such as animal feed. The fiber is also used to make cloth or rope, the thick leaves are used for cooking, and the male bud is eaten. The cultivated plants tend to have larger fruits and more pulp, compared to the wild ones, and the seeds don’t form completely and stay kind of soft. These plants are grown from suckers, which could explain why the seeds are not viable. When I toured Northern Vietnam with French and Vietnamese scientists at the end of 2018, I was surprised to see that nearly every restaurant had wild banana infused alcohol and that in every small town there were bunches of Musa balbisiana awaiting processing outside herbal shops. The seeds are extracted (and used in ways that are not clear to me) and the fruits are sliced and steeped in alcohol (inset).


There’s an unresolved debate as to whether edible bananas derived exclusively from ''Musa balbisiana'' exist. This plant, whose fruit look like those of a seedless cultivar, could be one. We saw it in Ha Long, Vietnam. It’s nearly identical to ''Musa balbisiana'', except for its plump and round fruit. Unfortunately, it was behind a fence and the security guard would not permit us to collect leaf samples, let alone suckers. It’s also unfortunate that the male bud had been removed (the bracts on the male bud of ''Musa balbisiana'' lift up, as opposed to those of ''Musa acuminata'' which roll up). I hope we can find it again.

There’s an unresolved debate as to whether edible bananas derived exclusively from Musa balbisiana exist. This plant, whose fruit look like those of a seedless cultivar, could be one. We saw it in Ha Long, Vietnam. It’s nearly identical to Musa balbisiana, except for its plump and round fruit. Unfortunately, it was behind a fence and the security guard would not permit us to collect leaf samples, let alone suckers. It’s also unfortunate that the male bud had been removed (the bracts on the male bud of Musa balbisiana lift up, as opposed to those of Musa acuminata which roll up). I hope we can find it again.


((Fei bananas|Fe'i bananas)) have followed a parallel but separate domestication path from the edible bananas derived from species in the ((Musa sections|''Musa'' section)). On the left is a Fe'i banana, called 'Wore' in PNG, and on the right is its presumptive wild ancestor ''Musa maclayi'', a species in the ''Callimusa'' section. Fe'i bananas' claim to fame is their bright yellow to orange pulp, which indicates high levels of ((Vitamin A in banana|carotenoids that the body converts to vitamin A)). These high carotenoid levels have another effect on the body that is nicely summed up in a common name we've common across for them in PNG, 'Yelo Pispis Banana'.

Fe'i bananas have followed a parallel but separate domestication path from the edible bananas derived from species in the Musa section. On the left is a Fe'i banana, called 'Wore' in PNG, and on the right is its presumptive wild ancestor Musa maclayi, a species in the Callimusa section. Fe'i bananas' claim to fame is their bright yellow to orange pulp, which indicates high levels of carotenoids that the body converts to vitamin A. These high carotenoid levels have another effect on the body that is nicely summed up in a common name we've common across for them in PNG, 'Yelo Pispis Banana'.


Presented in this spiral are 24 out of the approximately 130 or so different bananas we saw and documented on our [https://www.musalit.org/seeMore.php?id=18962|collecting mission to West New Britain], PNG. West New Britain is a province on the island of New Britain, the largest island of the [https://en.wikipedia.org/wiki/Bismarck_Archipelago|Bismarck archipelago]. The diversity of edible bananas in PNG is fascinating because so much of it is unique to the region. It's still possible to stumble across hard-to-classify specimens that upon subsequent genetic analysis are revealed to be unlike anything documented so far. Even bananas that look more familiar can turn out to be new-to-science cultivars.  You could design a banana in your mind of any size, shape, color, or unique attribute, and it’s not crazy to suggest it may already exist in PNG.

Presented in this spiral are 24 out of the approximately 130 or so different bananas we saw and documented on our collecting mission to West New Britain, PNG. West New Britain is a province on the island of New Britain, the largest island of the Bismarck archipelago. The diversity of edible bananas in PNG is fascinating because so much of it is unique to the region. It's still possible to stumble across hard-to-classify specimens that upon subsequent genetic analysis are revealed to be unlike anything documented so far. Even bananas that look more familiar can turn out to be new-to-science cultivars. You could design a banana in your mind of any size, shape, color, or unique attribute, and it’s not crazy to suggest it may already exist in PNG.


Another day in PNG, another diploid banana. The eye-catching immature reddish bananas on the left turn whitish yellow at maturity but remain swirly. 'Pagal' (top right) produces large and delicious fruits, and 'Mapalepa' is a variegated cultivar (bottom right). The diploids of PNG are a puzzle. We don’t know how they relate to each other. DNA evidence shows that they tend to cluster together, except for a few outliers. It’s hard to say anything specific about them at this point, beyond appreciating the diversity for what it is.

Another day in PNG, another diploid banana. The eye-catching immature reddish bananas on the left turn whitish yellow at maturity but remain swirly. 'Pagal' (top right) produces large and delicious fruits, and 'Mapalepa' is a variegated cultivar (bottom right). The diploids of PNG are a puzzle. We don’t know how they relate to each other. DNA evidence shows that they tend to cluster together, except for a few outliers. It’s hard to say anything specific about them at this point, beyond appreciating the diversity for what it is.


When I first came across this banana in 2011 in the Solomon Islands, I thought it was a triploid Pisang Awak cultivar, albeit a particularly large and vigorous selection. In 2016, I saw it again during a  [https://www.promusa.org/blogpost506-Collecting-bananas-in-Bougainville|collecting mission to Bougainville]. Having learned a thing or two about bananas, I called it as a tetraploid Pisang Awak-derived hybrid. Lo and behold, the molecular results showed that it was indeed one. There is some speculation as to the identity of the donor of the extra set of chromosomes. It could be a species from another section, the one that has the ancestors of Fe'i bananas. I saw it again in 2019 in West New Britain, PNG, where the photos were taken. This time I got to sample the fruit. Note the distinct orange cast to the fruit pulp and peel, probably evidence of its intersectional parentage. It tastes like a more flavorful Pisang Awak. It’s a massive plant that produces a huge bunch and has drooping leaves that almost touch the ground.

When I first came across this banana in 2011 in the Solomon Islands, I thought it was a triploid Pisang Awak cultivar, albeit a particularly large and vigorous selection. In 2016, I saw it again during a collecting mission to Bougainville. Having learned a thing or two about bananas, I called it as a tetraploid Pisang Awak-derived hybrid. Lo and behold, the molecular results showed that it was indeed one. There is some speculation as to the identity of the donor of the extra set of chromosomes. It could be a species from another section, the one that has the ancestors of Fe'i bananas. I saw it again in 2019 in West New Britain, PNG, where the photos were taken. This time I got to sample the fruit. Note the distinct orange cast to the fruit pulp and peel, probably evidence of its intersectional parentage. It tastes like a more flavorful Pisang Awak. It’s a massive plant that produces a huge bunch and has drooping leaves that almost touch the ground.


The diversity of banana fruits usually gets all the attention, but I find the male buds equally interesting. Here is a sampling of a few of the buds seen in West New Britain. The color of the bracts, the way they lift or roll, and overlap at the apex are also important traits to look at when identifying cultivars.

The diversity of banana fruits usually gets all the attention, but I find the male buds equally interesting. Here is a sampling of a few of the buds seen in West New Britain. The color of the bracts, the way they lift or roll, and overlap at the apex are also important traits to look at when identifying cultivars.


Cruising the island of [https://en.wikipedia.org/wiki/Rarotonga|Rarotonga] in the Cook Islands with Papa Moe to get a sense of the place and of the banana diversity. It takes only a couple of hours to drive all the roads on the island. The fruit haul we amassed in one afternoon were gifts from local residents, and a good sign of the welcoming and friendly nature of the small community. In the lot are bananas that are traditional Pacific cultivars brought by early settlers, mixed with more recent introductions.

Cruising the island of Rarotonga in the Cook Islands with Papa Moe to get a sense of the place and of the banana diversity. It takes only a couple of hours to drive all the roads on the island. The fruit haul we amassed in one afternoon were gifts from local residents, and a good sign of the welcoming and friendly nature of the small community. In the lot are bananas that are traditional Pacific cultivars brought by early settlers, mixed with more recent introductions.


Snacking on a Fe’i banana (called Utu in the Cook Islands) in Celine’s mountain garden (left). Celine transplanted several Utu plants growing feral in the forests of Takuvaine valley. She has three, maybe four forms of Utu in her garden, but says that there are more forms to be found further up the mountain. Besides the color of the fruit, Fe’i bananas are easily recognized by their erect inflorescence (top right) and the blue/purple sap seeping out a cross-section of the ((Banana pseudostem|pseudostem)) (bottom right).

Snacking on a Fe’i banana (called Utu in the Cook Islands) in Celine’s mountain garden (left). Celine transplanted several Utu plants growing feral in the forests of Takuvaine valley. She has three, maybe four forms of Utu in her garden, but says that there are more forms to be found further up the mountain. Besides the color of the fruit, Fe’i bananas are easily recognized by their erect inflorescence (top right) and the blue/purple sap seeping out a cross-section of the pseudostem (bottom right).


'Tara Puakatoro' (meaning cow horn) is a classic False-Horn ((Plantain subgroup|Plantain)), in that it produces a few large fruits and the male bud degenerates quickly after the fruits are formed. Even though the name refers to a recently introduced animal, this cultivar has been reported as having been in the Cook Islands for a very long time. Plantains have been found in islands further west and are related to traditional Pacific groups, like ((Iholena subgroup|Iholena)) and ((Maoli-popoulu subgroup|Maoli-Popoulu)) (see below). I suppose it’s time for me to start considering them as a traditional group in the Pacific, instead of as recent introductions.

'Tara Puakatoro' (meaning cow horn) is a classic False-Horn Plantain, in that it produces a few large fruits and the male bud degenerates quickly after the fruits are formed. Even though the name refers to a recently introduced animal, this cultivar has been reported as having been in the Cook Islands for a very long time. Plantains have been found in islands further west and are related to traditional Pacific groups, like Iholena and Maoli-Popoulu (see below). I suppose it’s time for me to start considering them as a traditional group in the Pacific, instead of as recent introductions.


In Samoa, we stumbled on the rare sight of two Maoli-Popoulu cultivars on the same ((Morphology of banana plant|mat)). The shoot on the right is 'Fa'i Samoa Aumalie', and the one on the left 'Fa'i Samoa Pupuka'. Normally, the shoots on a mat are genetically identical to each other (edible bananas reproduce vegetatively through shoots, called suckers, that sprout on the rhizome). Sometimes, however, mutations and so-called epigenetic processes disrupt the natural cloning process. If the mutant shoot's traits appeal to farmers, it will be propagated and become a new cultivar (that’s how diversity has been created since cultivars became essentially sterile). In this case, we don't know which shoot spontaneously changed and whether it’s a one-off event. What’s also interesting is that these Maoli-Popoulu cultivars share morphological characteristics with Plantains, even though they are not identified as such. 'Fa'i Samoa Aumalie' is like a French type (large bunch with a fully developed male bud), whereas 'Fa'i Samoa Pupuka' is like a False Horn type (fewer larger fruits and a quickly degenerative male bud).

In Samoa, we stumbled on the rare sight of two Maoli-Popoulu cultivars on the same mat. The shoot on the right is 'Fa'i Samoa Aumalie', and the one on the left 'Fa'i Samoa Pupuka'. Normally, the shoots on a mat are genetically identical to each other (edible bananas reproduce vegetatively through shoots, called suckers, that sprout on the rhizome). Sometimes, however, mutations and so-called epigenetic processes disrupt the natural cloning process. If the mutant shoot's traits appeal to farmers, it will be propagated and become a new cultivar (that’s how diversity has been created since cultivars became essentially sterile). In this case, we don't know which shoot spontaneously changed and whether it’s a one-off event. What’s also interesting is that these Maoli-Popoulu cultivars share morphological characteristics with Plantains, even though they are not identified as such. 'Fa'i Samoa Aumalie' is like a French type (large bunch with a fully developed male bud), whereas 'Fa'i Samoa Pupuka' is like a False Horn type (fewer larger fruits and a quickly degenerative male bud).