The present work is part of a continuing study on Musa taxa by the author. Several molecular analyses support acceptance of only two Musa sections, M. sect. Musa and M. sect. Callimusa. Musa sect. Rhodochlamys is synonymized with M. sect. Musa and M. sect. Australimusa and M. sect. Ingentimusa are treated as synonyms of M. sect. Callimusa. Species lists are provided for the two accepted sections.
The production of bananas is threatened by rapid spreading of various diseases and adverse environmental conditions. The preservation and characterization of banana diversity is essential for the purposes of crop improvement. The world's largest banana germplasm collection maintained at the Bioversity International Transit Centre (ITC) in Belgium is continuously expanded by new accessions of edible cultivars and wild species. Detailed morphological and molecular characterization of the accessions is necessary for efficient management of the collection and utilization of banana diversity. In this work, nuclear DNA content and genomic distribution of 45S and 5S rDNA were examined in 21 diploid accessions recently added to ITC collection, representing both sections of the genus Musa. 2C DNA content in the section Musa ranged from 1.217 to 1.315 pg. Species belonging to section Callimusa had 2C DNA contents ranging from 1.390 to 1.772 pg. While the number of 45S rDNA loci was conserved in the section Musa, it was highly variable in Callimusa species. 5S rRNA gene clusters were found on two to eight chromosomes per diploid cell. The accessions were genotyped using a set of 19 microsatellite markers to establish their relationships with the remaining accessions held at ITC. Genetic diversity done by SSR genotyping platform was extended by phylogenetic analysis of ITS region. ITS sequence data supported the clustering obtained by SSR analysis for most of the accessions. High level of nucleotide diversity and presence of more than two types of ITS sequences in eight wild diploids pointed to their origin by hybridization of different genotypes. This study significantly expands the number of wild Musa species where nuclear genome size and genomic distribution of rDNA loci is known. SSR genotyping identified Musa species that are closely related to the previously characterized accessions and provided data to aid in their classification. Sequence analysis of ITS region provided further information about evolutionary relationships between individual accessions and suggested that some of analyzed accessions were interspecific hybrids and/or backcross progeny.
The recent South Asian Tsunami has brought world-wide awareness to the effects of major disasters upon all segments of society. Vulnerable populations such as the disabled, children, or the elderly are at particular risk in a disaster and it is vital to consider their special needs in the design of disaster preparedness and warning systems. Additionally, tourists, recent immigrants, and refugees face challenges when confronted with disaster in unfamiliar locations, linguistically isolated, and in need of assimilating lifesaving information and guidance quickly when under stress. Attention to the requirements for persons with disabilities may also benefit the greater general population which can find itself situationally disabled. Information and Communications Technology based upon accessible design principles is part of the solution. Understanding of psychology, ergonomics, and information design is vital, as are the unique perceptual, cognitive, physical, and linguistic challenges that can influence the efficacy of the message. These issues are among those addressed in an ongoing project in Urakawa, Japan, which is developing a disaster preparedness information system that meets the needs of persons with disabilities.
The center of diversity of the genus Musa (Musaceae) is in Southeast Asia, a region not studied in detail and where new species and varieties continue to be reported. A new wild banana species, M. chunii Häkkinen from Yunnan, China is described and illustrated based on observed morphological characteristics in the field. This extremely rare new species was only found in Tongbiguan Nature Reserve, Dehong District, West Yunnan.A key to M. chunii and related taxa is provided. In addition, critical notes regarding M. rubra Kurz identity are given.
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