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Musa itinerans


Musa itinerans

Wild species, Musa itinerans

Order

Zingiberales

Family

Musaceae

Genus

Musa

Section

Musa

Species
Musa itinerans

Musa itinerans is a wild species of bananas first described by Ernest E. Cheesman from plants grown at the Imperial College of Tropical Agriculture's field collection in Trinidad[1]. The seeds had been collected in an "evergreen forest at Tagwin, Myitkyina, Upper Burma" (Myanmar). Its name refers to its "travelling" habit, as a sucker can emerge two meters away or more from the mother plant.

Kew's world checklist recognizes 8 varieties, including M. itinerans var. itinerans[2]. It was misidentified as Musa wilsonii in Chinese literature, a confusion that was clarified in 2001[3].

During his 1954-55 banana collecting expedition to southeast Asia, Norman Simmonds observed variability in fruit colour and the compound tepals of the male flowers in Thailand and India[4].

Main morphological characteristics

The diagnostic character for this species is its long rhizome. Cheesman describes the pseudostem as 4 m or more in height and 20-25 cm in diameter at the base. The inflorescence is semi-pendulous and the peduncle is velvety. The inside of the bracts is yellow. The individual fruits are about 10 cm in length and 3 cm in diameter and relatively spread out on the bunch. They are not very curved[1].

Distribution and habitat

M. itinerans is widely dispersed throughout continental southeast Asia, from northeast India to Vietnam and adjacent islands[5]. In China, it is usually found in secondary tropical rainforests[3].

Genome sequencing

The genome of an individual collected on Hainan Island, China, was sequenced in 2016[6]. The assembled genome size is 462.1 Mb, covering 75.2% of the 615.2Mb genome and containing 32,456 predicted protein-coding genes. The sequence is available from the Banana Genome Hub[7]

The chloroplast genome was also sequenced[8]. The DNA came from leaves collected in China's Yunnan province. The complete chloroplast genome was found to be 168,985 bp long, to contain 113 unique genes, including 79 protein-coding genes, 30 transfer RNA genes, and four ribosomal RNA genes.

Musa itinerans and Musa acuminata are estimated to have diverged from a common ancestor around 5.8 million years ago[6]

Reaction to pests and diseases

None of the plants of Musa itinerans exposed to the Fusarium oxysporum f. sp. cubense strain known as TR4 developed symptoms of Fusarium wilt in field and greenhouse trials[9].

References

2. Type Musa itinerans in the search field of the World Checklist of Selected Plant Families
3. Liu, A.Z., Li, D.Z. and Li, X.W. 2002. Taxonomic notes on wild bananas (Musa) from China. Botanical Bulletin of Academia Sinica 43(1):77-81.
4. Simmonds, N.W. 1956. Botanical results of the banana collecting expedition, 1954-5. Kew Bulletin(3):463-489.
5. Häkkinen, M., Hong, W. and Ge, X.J. 2008. Musa itinerans (Musaceae) and its intraspecific taxa in China. Novon 18(1):50-60.
8. Li, W., Liu, Y. and Gao, L.Z. 2017. The complete chloroplast genome of the endangered wild Musa itinerans (Zingiberales: Musaceae). Conservation Genetics Resources (First online).
9. Li, W.M., Dita, M., Wu, W., Hu, G.B., Xie, J.H. and Ge, X.J. 2015. Resistance sources to Fusarium oxysporum f. sp. cubense tropical race 4 in banana wild relatives. Plant Pathology 64(5):1061-1067.

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