Genetic diversity study of dessert-type banana cultivars in Mauritius using low-cost SNP discovery technology
Introduced during the 17th century, commercial and non-commercial banana cultivars are now diverse in Mauritius. Excepting 'Dwarf Cavendish', most cultivars are known by local names. Based on morphological characteristics, cultivars appear to belong to two main groups, those with yellow waxy peel and soft texture ('Mamoul' group) and those having a glossy canary-yellow peel with a sweet-acidulated taste and dry texture when ripe ('Gingeli' group). Historical cultivar records do not concur with the phenotypic features of 'Gingeli' banana. Apart from one study differentiating between A and B genotypes, no molecular characterization has so far been carried out. We sought to genetically identify the most common cultivars, including the dessert-type bananas. Therefore 22 local and international accessions were studied at the Plant Breeding and Genetics Laboratory using a low-cost gel-based 'ecotilling' approach in 10 target genes. The aim was to determine accession identities thus allowing comparison with international accessions. A low-cost approach using a self-extracted enzyme and electrophoresis common to most laboratories was adopted to assess the suitability of this technique for laboratories with limited resources. Robust polymorphisms were detected among cultivars which allowed a clustering of local germplasm with each other and with international ones. This assessment agreed with grouping based on phenotypic traits. The 'Mamoul' types clustered with the Pisang Awak subgroup (ABB genome) while the 'Gingeli' clustered with the Silk subgroup (AAB genome). This study has established the genetic diversity among Mauritian dessert-type banana cultivars and compared them with international accessions. Low-cost ecotilling can detect natural polymorphism in banana to differentiate clones in a natural population, at group and subgroup levels, and is appropriate for countries with limited facilities. Further work will study and sequence other clones. Better characterization of 'Gingeli' can be accomplished by investigating more gene targets.
Jhurree-Dussoruth, B., Jankowicz-Cieslak, J. and Till, B.J. (2016). Genetic diversity study of dessert-type banana cultivars in Mauritius using low-cost SNP discovery technology. Acta Hortic. 1114, 45-52
agarose gel, cleavage, enzymatic mismatch, nucleotide polymorphism, morphological descriptors, Musa, polyacrylamide gel