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 Trinidad1 . 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. itinerans2 . It was misidentified as Musa wilsonii in Chinese literature, a confusion that was clarified in 20013 .
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 India4 .
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 curved1 .
Distribution and habitat
M. itinerans is widely dispersed throughout continental southeast Asia, from northeast India to Vietnam and adjacent islands5 . In China, it is usually found in secondary tropical rainforests3 .
Genome sequencing
The genome of an individual collected on Hainan Island, China, was sequenced in 20166 . 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 Hub7 .
The chloroplast genome was also sequenced8 . 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 ago6 .
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 trials9 .