Browsing by Author "Janssens, Steven"

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    Filling the gaps in gene banks: Collecting, characterizing,and phenotyping wild banana relatives of Papua NewGuinea
    (John Wiley and Sons Inc, 2020-11-20) Eyland, David; Breton, Catherine; Sardos, Julie; Kallow, Simon; Panis, Bart; Swennen, Rony; Paofa, Janet; Tardieu, François; Welcker, Claude; Janssens, Steven
    Since natural habitats are disappearing fast, there is an urgent need to collect, characterize, and phenotype banana (Musa spp.) crop wild relatives to identify unique genotypes with specific traits that fill the gaps in our gene banks. We report on a collection mission in Papua New Guinea carried out in 2019. Seed containing bunches were collected from Musa peekelii ssp. angustigemma (N.W.Simmonds) Argent (3), M. schizocarpa N. W. Simmonds (4), M. balbisiana Colla (3), M. acuminata ssp. banksii (F. Muell.) Simmonds (14), M. boman Argent (3), M. ingens Simmonds (2), M. maclayi ssp. maclayi F.Muell. ex Mikl.-Maclay (1), and M. lolodensis Cheesman (1). This material, together with the seeds collected during a previous mission in 2017, form the basis for the development of a wild banana seed bank. For characterization and phenotyping, we focused on the most ubiquitous indigenous species of Papua New Guinea: M. acuminata ssp. banksii, the ancestor of most edible bananas. We calculated that the median genomic dissimilarity of the M. acuminata ssp. banksii accessions was 4% and that they differed at least 5% from accessions present in the International Transit Centre, the world's largest banana gene bank. High-throughput phenotyping revealed drought avoidance strategies with significant differences in root/shoot ratio, soil water content sensitivity, and response towards vapor pressure deficit (VPD). We deliver a proof of principle that the wild diversity is not yet fully covered in the gene banks and that wild M. acuminata ssp. banksii populations contain individuals with unique traits, useful for drought tolerance breeding programs.
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    Using seminatural and simulated habitats for seed germination ecology of banana wild relatives
    (John Wiley and Sons Ltd, 2021-10-10) Kallow, Simon; Quaghebeur, Katrijn; Panis, Bart; Janssens, Steven; Dickie, John; Gueco, Lavernee; Swennen, Rony; Vandelook, Filip
    Ecologically meaningful seed germination experiments are constrained by access to seeds and relevant environments for testing at the same time. This is particularly the case when research is carried out far from the native area of the studied species. Here, we demonstrate an alternative—the use of glasshouses in botanic gardens as simulated-natural habitats to extend the ecological interpretation of germination studies. Our focal taxa were banana crop wild relatives (Musa acuminata subsp. burmannica, Musa acuminata subsp. siamea, and Musa balbisiana), native to tropical and subtropical South-East Asia. Tests were carried out in Belgium, where we performed germination tests in relation to foliage-shading/exposure to solar radiation and seed burial depth, as well as seed survival and dormancy release in the soil. We calibrated the interpretation of these studies by also conducting an experiment in a seminatural habitat in a species native range (M. balbisiana—Los Baños, the Philippines), where we tested germination responses to exposure to sun/shade. Using temperature data loggers, we determined temperature dynamics suitable for germination in both these settings. In these seminatural and simulated-natural habitats, seeds germinated in response to exposure to direct solar radiation. Seed burial depth had a significant but marginal effect by comparison, even when seeds were buried to 7 cm in the soil. Temperatures at sun-exposed compared with shaded environments differed by only a few degrees Celsius. Maximum temperature of the period prior to germination was the most significant contributor to germination responses and germination increased linearly above a threshold of 23℃ to the maximum temperature in the soil (in simulated-natural habitats) of 35℃. Glasshouses can provide useful environments to aid interpretation of seed germination responses to environmental niches.