Comparative analysis of phenotypic and genotypic diversity among plantain landraces (Musa spp., AAB group)

Genetic diversity amongst 76 plantain landraces has been studied using RAPD analysis at two levels of intensity and compared with groupings based on phenotypic indices and morphotype. There was a good correlation (R²=0.78) between estimates of genetic diversity based on 76 RAPD bands and 164 RAPD bands. However, there was a poor correlation between RAPD-based estimates of genetic diversity and a phenotypic index based on agronomic characters. There was also a poor correlation between RAPD analyses and morphotype group (based on bunch type and stature). These results suggest that the traditional designations of plantain landraces based on morphotype do not provide a true reflection of overall genetic divergence. Similarly, classification systems using phenotypic indices based on agronomic characters may not provide accurate taxonomic differentiation. The level of genetic divergence within morphogroups based on bunch type suggests that True Horn plantains are derived from False Horn plantains which in turn are derived from French plantains. Genetic divergence was found to be generally quite low within the plantain landrace genepool, which is consistent with the proposed evolution of this germplasm through somatic mutation of a relatively small number of introductions. However, putative synonyms/duplicates have been shown to be genetically distinct. In contrast, a group of 12 landraces have been identified that are highly distinct from one another (showing 20–35% dissimilarity). Fertile members of this group may be useful for generating genetically diverse 2x and 4x breeding populations that can be used in breeding secondary triploid hybrid plantain varieties. Received: 8 January 2000 / Accepted: 2 March 2000     

Lectotypification of two Musa sections (Musaceae)

The present work is part of a continuing study to revise the old names in Musa and aims to clarify the taxonomy in the sections Rhodoclamys and Callimusa. Lectotypes are designated here for Musa sect. Callimusa and M. sect. Rhodochlamys . These sections were first erected without the indication of a type species.     

Genetic Diversity and Population Assessment of Musa L. (Musaceae) Employing CDDP Markers

Plant Molecular Biology Reporter - Sixty-six accessions of Musa genus with different genomic groups that consisted of wild relatives and cultivated lines were obtained from the International...     

影响体胚发生途径香蕉(Musa spp.,AAB Group)植株再生的因素

香蕉品种‘Agbagaba'和‘Orishele'的胚性细胞悬浮系(ECS)在液体培养基中分别预培养1和2周后,将其接种在RD1和M3培养基上,于光照或黑暗条件下进行体胚的再生.从沉积细胞体积(SCV)为1 mL(1 mL SCV)的ECS获得的再生体胚数量因预培养时间、再生培养基的种类及培养条件的不同而异.植株的再生率及从1 mL SCV的ECS获得的再生植株数量也受上述体胚再生条件的间接影响.     

Musa aurantiaca (Musaceae) and its intraspecific taxa in India

Musa aurantiaca Baker (Musaceae) is distributed from northeast India, Tibet to northern Myanmar. In the present study its intraspecific taxa are thoroughly investigated. Two new varieties are described and illustrated based on live plants in the field: M. aurantiaca Baker var. homenborgohainiana Gogoi and M. aurantiaca Baker var. jengingensis Gogoi. A key to the varieties of Musa aurantiaca Baker and closely related taxa is also provided.     

Clonal Fidelity and Variation in Plantain (Musa AAB) Regenerated from Vegetative Stem and Floral Axis Tips in vitro

Recognition of a phenotypically distinct 'French-type' plantain(Musa AAB) designated 'Superplatano' (Superplantain) promptedevaluation of in vitro micropropagation as a means of generatingsufficient numbers of plants for field evaluation in three locationsin Puerto Rico. A multi-faceted study designed to evaluate relationshipsbetween different aseptic culture procedures and morphologicalorigins of primary explants was carried out. Vegetative budsfrom various positions relative to the mother corm (definedby cardinal points on the compass) and explants from the floralaxis of 'Maricongo' (the 'False-Horn', or florally determinatetype 'progenitor' of 'Superplatano'), and 'Superplatano' (a'French-type') were used as starting materials. Responses underfield conditions were studied using a number of parameters includingyield of commercially marketable fruits. We compared four populationsof shoots, each of which derived from at least three differentshoots from within one mat, shoots derived from vegetative andfloral material from the same mat for both 'Maricongo' and 'Superplatano',and shoots derived from a number of floral buds of the sameclone ('Maricongo') all of which were in culture for the samelength of time. 'Superplatano' was stable whether from vegetativecorm or floral bud apex. This shows conclusively that if thestarting point in the micropropagation process is a stable Musaclone, our tissue culture procedure is reliable. Considerablevariation in bunch phenotype was observed, however, in plantsregenerated from ten of 12 shoot and floral meristems startedfrom the 'False-Horn'-type 'Maricongo'. Change from 'False-Horn'-type(determinate) to 'French'-phenotype (indeterminate) was evidentin each of the three locations. Frequency of bunch reversionvaried from 0·4 to 100%, but was confined to individualoriginating stem tips rather than clones. The most dramaticbunch phenotypic change occurred in plants regenerated fromclone 3. All plants regenerated from shoot 3-North bore 100%'French-type' bunches. However, reversion in plants regeneratedfrom shoot 3-West was only 1·8%, and no bunch phenotypicchange was observed in plants from shoot 3-East. Plants regeneratedfrom both shoot and male floral axis tips in 'Maricongo' clone4 also bore 'French-type' bunches. Frequency of bunch reversionfrom shoot 4-East was 0·4% as compared to 2·6%from 4-floral. Bunch reversion occurred at the frequency of2·0% when plants were regenerated from clone 6-floral.No bunch reversion was observed in plants regenerated from asingle shoot tip in clones 1-West and 5-floral. No dwarfismwas encountered in any of the tissue culture-derived plants.We conclude that tissue culture per se plays a very small role,if any, in the direct induction of off-types. Pre-existing characteristicsof the primary explant determines whether products of a multiplicationshow fidelity or not. Our data suggest that 'Maricongo' is achimera and that 'Superplatano' is revertant off-type that resultswhen breakdown of the chimera occurs. Large numbers of stable'Superplatano' were produced from unstable 'Maricongo' and thisaffirms the value of micropropagation for generation of cloneswith desirable bunch phenotype.Copyright 1993, 1999 AcademicPress Musa, plantains, bananas, tissue culture, clonal multiplication, somaclonal variation, phenotype     

Growth Parameters of Yield of Plantain (Musa cv. AAB)

The performance of the crop plant and the ‘ratoon’plant (lateral shoot succeeding the harvested main shoot) of65 medium-sized False Horn plantains (Musa cv. AAB) was studiedby measuring vegetative and inflorescence (bunch) parameters.From significant regressions between different parameters itappears that taller pseudostems produce leaves at a faster rate,flower earlier and produce heavier infructescences which needmore time to mature. A high yield is determined by vigorousinitial growth of the planted sucker (lateral root). Beforeflowering, there is no sink competition between ratoon and mainpseudostem growth, and fast-growing main pseudostems are accompaniedby fast-growing ratoons. After flowering, competition occursbetween the fructifying inflorescence, a preferential sink andthe ratoon. The results indicate that plantain should not beconsidered as an annual crop. Growth, development, production parameters, bananas, plantains     

Musa chunii Hakkinen, a new species (Musaceae) from Yunnan,China and taxonomic identity of Musa rubra

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 Hakki-nen 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.     

Genetic diversity and population genetic structure of wild banana Musa ornata (Musaceae) in Mexico

The wild banana Musa ornata is an inhabitant of the tropical regions of Mexico characterized by patches of tropical rainforest. The overexploitation of its habitat has caused the extinction of several populations affecting diversity and population genetic structure of remaining ones. We used microsatellite markers to determine the genetic diversity and the population’s genetic structure of all extant populations. The thirty-two microsatellite loci previously characterized for M. acuminata and M. balbisiana were tested in M. ornata. Only twelve amplified. From these seven were polymorphic and were used for genetic analyses. The Nei’s diversity estimator shows low levels of genetic diversity (H _e = 0.263) with a mean of 4.40 alleles per locus. Excess homozygosity was evident in all populations indicating high levels of inbreeding. F _ST pairwise analyses and AMOVA indicated low genetic differentiation. However, 28 % of private alleles were registered, suggesting limited gene flow. Genetic distances, Jaccard’s coefficient and principal component analysis showed a good correspondence to geographical locations. The Mantel test performed was not significant. The results support the hypothesis of recent fragmentation events; therefore, not enough time has passed to detect differences between populations. However, it is also likely that results are caused by factors such as bottleneck, decline in pollinator populations, self-pollination and/or a tendency towards clonal reproduction. It is proposed that the preservation strategy focuses on maintaining all the remaining populations and ensuring their connectivity, so as to maintain gene flow and increase the genetic diversity of this species.     

Musa paramjitiana sp. nov. (Musaceae) from Andaman and Nicobar Islands,India

A new species of wild banana, Musa paramjitiana L. J. Singh, from the Andaman Islands, India is described and illustrated, and its conservation status is assessed. A key to the species of Musa L. from Andaman and Nicobar Islands is also provided.     

Determinate Floral Buds of Plantain (Musa AAB) as a Site of Adventitious Shoot Formation

Floral buds of the ‘False Horn’ plantain clonesMusa (AAB) ‘Harton Verde’, ‘Harton Negra’,and ‘Currare’ terminate in a large single floralstructure. The apices of these floral buds are here designatedas determinate since they have lost the ability to produce additionalfloral initials or buds. Terminal peduncle segments can be culturedin a modified Murashige and Skoog (1962) medium supplementedwith N⁶-benzyl-aminopurine (5 mg I^–1). Under these conditions,this apparent inability to yield buds can be overcome as vegetativeshoot clusters form in the axils of the bracts. Rooted plantletsare obtainable by treating shoots with naphthaleneacetic acid(1 mg I^–1) and activated charcoal (0.025%). The adventitiousorigin of the shoots has been established. Musa cultivars, plantains, floral bud, adventitious buds, tissue culture     

Musa chunii Häkkinen,a new species (Musaceae) from Yunnan,China and taxonomic identity of Musa rubra

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.     

Nuclear genome size and genomic distribution of ribosomal DNA in Musa and Ensete (Musaceae): taxonomic implications

Nuclear DNA content and genomic distributions of 5S and 45S rDNA were examined in nineteen diploid accessions of the genus Musa representing its four sections Eumusa, Rhodochlamys, Callimusa and Australimusa, and in Ensete gilletii, which was the outgroup in this study. In the Eumusa (x = 11), 2C DNA content ranged from 1.130 to 1.377 pg, M. balbisiana having the lowest DNA content of all sections. M. beccarii (x = 9), a representative of Callimusa, had the highest 2C nuclear DNA content (1.561 pg). Species belonging to Rhodochlamys (x = 11) and Australimusa (x = 10) had 2C DNA contents ranging from 1.191 to 1.299 pg and from 1.435 to 1.547 pg, respectively. E. gilletii (x = 9) had 2C DNA content of 1.210 pg. The number of 5S rDNA loci in Musa varied from 4 to 8 per diploid cell. While different numbers of 5S rDNA loci were observed within Eumusa and Rhodochlamys, four 5S rDNA loci were observed in all accessions of Australimusa. M. beccarii (Callimusa) and E. gilletii contained 5S rRNA gene clusters on five and six chromosomes, respectively. The number of 45S rDNA loci was conserved within individual sections. Hierarchical cluster analysis of genome size, number of chromosomes and 45S rDNA sites suggested a close relationship between Rhodochlamys and Eumusa; Australimusa was clearly separated as were M. beccarii and E. gilletii. Within the Eumusa-Rhodochlamys group, M. balbisiana, M. schizocarpa and M. ornata formed distinct subgroups, clearly separated from the accessions of M. acuminata, M. mannii, M. laterita and M. velutina, which formed a tight subgroup. The results expand the knowledge of genome size and genomic distribution of ribosomal DNA in Musa and Ensete. They aid in clarification of the taxonomical classification of Musa and show a need to supplement the analyses on the DNA sequence level with cytogenetic studies.     

Mutagenicity of the Musa paradisiaca (Musaceae) fruit peel extract in mouse peripheral blood cells in vivo

Plants are a source of many biologically active products and nowadays they are of great interest to the pharmaceutical industry. In the present study, the mutagenic potential of the Musa paradisiaca fruit peel extract was assessed by the single-cell gel electrophoresis (SCGE) and micronucleus assays. Animals were treated orally with three different concentrations of the extract (1000, 1500, and 2000 mg/kg body weight). Peripheral blood cells of Swiss mice were collected 24 h after treatment for the SCGE assay and 48 and 72 h for the micronucleus test. The results showed that the two higher doses of the extract of M. paradisiaca induced statistically significant increases in the average numbers of DNA damage in peripheral blood leukocytes for the two higher doses and a significant increase in the mean of micronucleated polychromatic erythrocytes in the three doses tested. The polychromatic/normochromatic erythrocyte ratio scored in the treated groups was not statistically different from the negative control. The data obtained indicate that fruit peel extract from M. paradisiaca showed mutagenic effect in the peripheral blood cells of Swiss albino mice.     

Field Evaluation of Selected Formulations of Beauveria bassiana for the Management of the Banana Weevil ( Cosmopolites sordidus ) on Plantain ( Musa spp., AAB Group)

Field experiments were undertaken to determine the efficacy of two formulations of Beauveria bassiana isolate IMI331094 against the banana weevil, Cosmopolites sordidus . Oil palm kernel cake-based formulation of conidia (OPKC-C) and conidial powder (CP) were applied to the planting holes and suckers. After artificial weevil release, OPKC-C and CP gave the same high level of weevil mortality (75%) compared with only 1% in the untreated control. Under natural levels of weevil infestation, 42% of weevils collected from suckers treated with OPKC-C died compared with 6% and 3% weevil mortality for CP and the untreated control, respectively. None of the suckers treated with OPKC-C died during the study period (60 days) while 17% and 19% of suckers from the CP treatment and the untreated control respectively, were killed. A study on the spread of fungal conidia using artificially infected and non-infected adult weevils showed a possible dissemination of B. bassiana conidia from infected weevils up to 18 m from the release point. On the basis of these results, the isolate IMI330194 of B. bassiana could clearly play a key role in the management of C. sordidus adults on plantain.     

Patterns of plant functional traits in the biogeography of West African grasses (Poaceae)

Grasses (Poaceae) are the largest family of vascular plants in Burkina Faso with 254 species. In the savannahs they are the most important family in terms of abundance and species richness, in other habitats, such as gallery forests, there are only few species. On the country scale there is a change in growth form: while in the Sahelian north most grasses are small therophytes, the Sudanian south is characterized by tall, often perennial grasses. To analyse these patterns in detail, we compiled a database on grass occurrences and used it in an ecological niche modelling approach with the programme Maxent to obtain country‐wide distribution models. Secondly we used data on photosynthetic type, height, leaf width and growth form to aggregate the species distributions and quantified the relative importance of functional groups per grid cell. Pronounced latitudinal differences could be shown for life forms, photosynthesis and size: the drier north is characterized by smaller, mainly therophytic grasses with a high share of C4 NAD‐ME photosynthesis, while the more humid south is characterized by tall, often hemicryptophytic grasses with C4 NADP‐ME photosynthesis. For leaf width, no clear country‐wide patterns could be observed, but local differences with more broad‐leaved grasses in humid areas.