Exploring the diversity of traditional banana cultivars in Oman and identifying their potential resistance to important biotic stresses.
The objectives of this project are (i) to combine morphological and molecular genetic data with historical trading records and ethnobotanical work to investigate the phylogeographical relationships and diversity of traditional banana (Musa spp.) and (ii) to screen these cultivars for disease and pest resistance/tolerance. For this purpose, banana stands in selected oases in Northern Oman and in the monsoon-influenced region of Salalah in Southern Oman will be surveyed and banana cultivars encountered will be morphologically characterized using Musa-specific identification keys. Molecular genetic characterization will follow, using amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs) on 1022 accessions from Oman (500 from Northern and Southern Oman, respectively, in addition to 22 accessions already collected in previous collection missions) and a total of 50 accessions from East African islands: Zanzibar, Comoros and Madagascar (grand total of 1082 samples). In the AFLP analyses, eight established primer combinations will be applied while for the SSR analyses, 15 nuclear SSR markers will be used. The simultaneous application of both marker types and the comparison of the molecular results with key morphological traits will contribute to the understanding of the diffusion, diversity and evolution of Musa germplasm, and provide insights into the origin of ancient banana cultivars from selected sites in and around Oman. Parallel to the molecular characterization of accessions, traditional cultivars will be screened in vitro for resistance/tolerance to four of the most important banana pests and diseases: the Burrowing Nematode (Radopholus similis), the Banana Weevil (Cosmopolites sordidus) and the fungi Fusarium oxysporum f.sp. cubense (FOC), which causes Panama Disease and Mycosphaerella fijiensis, the causal agent of Black Sigatoka Leaf Streak. Bananas are already, and with international trade linking far-flung regions of the world, increasingly being threatened by the movement of pests and diseases. There is no resistance to R. similis or C. sordidus nor to Black Sigatoka in commercial cultivars, and a new race of Panama Disease (FOC TR4), which affects cultivars formerly classified as Panama Disease resistant, has emerged. The search for tolerance or resistance traits in banana plants is therefore all the more pressing. Historical banana cultivation sites, such as the oases in Oman, are potential hotspots for germplasm diversity, where such resistance/tolerance traits may be discovered.
An important element of the project is capacity building in the identification and analysis of plant genetic resources and as well as screening for disease and pest resistance/tolerance. This involves the training of Omani doctoral candidates and master students in (i) the taxonomic characterization, and either (ii) the molecular characterization or (iii) screening for resistance/tolerance of banana germplasm from the region in a collaborative framework with specialists from Oman and Europe.