5 research outputs found

    Pycreus rubidomontanus (Cyperaceae), a widespread but undescribed species from tropical West Africa

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    Pycreus rubidomontanus is described as a new species. It is relatively widespread in tropical West Africa where it had been confused up to present with P. atrorubidus, a very rare endemic species from Zambia in south-central Africa that probably is known only from the type gathering. Differences between these and other similar species are discussed and the new species is copiously illustrated

    Novel Insights into the Inheritance of Gibberella Ear Rot (GER), Deoxynivalenol (DON) Accumulation, and DON Production

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    Gibberella ear rot (GER) is an important fungal ear pathogen of maize that causes ear rot and toxin contamination. Most previous works have only dealt with the visual symptoms, but not with the toxins of GER. As food and feed safety rankings depend on toxin contamination, including deoxynivalenol (DON), without toxins, nothing can be said about the risks involved in food and feed quality. Therefore, three susceptible, three medium-susceptible, and three medium-resistant mother lines were crossed with three testers with differing degrees of resistance and tested between 2017–2020. Two plot replicates and two fungal strains were used separately. The highest heterosis was found at the GER% with a 13% increase across 27 hybrids, including 7 hybrids showing negative heterosis (a higher hybrid performance above the parental mean), with a variance ranging between 63.5 and −55.4. For DON, the mean heterosis was negative at −35%, and only 10 of the 27 hybrids showed a positive heterosis. The mean heterosis for DON contamination, at 1% GER, was again negative (−19.6%, varying between 85% and 224%). Only 17 hybrids showed heterosis, while that of the other 17 was rated higher than the parental mean. A positive significant correlation was found only for GER% and DON; the other factors were not significant. Seven hybrids were identified with positive (2) or negative (5) heterosis for all traits, while the rest varied. For DON and GER, only 13 provided identical (positive or negative) heteroses. The majority of the hybrids appeared to diverge in the regulation of the three traits. The stability of GER and DON (variance across eight data sets) did not agree—only half of the genotypes responded similarly for the two traits. The genetic background for this trait is unknown, and there was no general agreement between traits. Thus, without toxin analyses, the evaluation of food safety is not possible. The variety in degrees of resistance to toxigenic fungi and resistance to toxin accumulation is an inevitable factor

    A broader circumscription of Bulbostylis including Nemum (Abildgaardieae: Cyperaceae)

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    Phylogenetic hypotheses and morphological characterizations of genera in the Abildgaardieae have suggested that current generic circumscriptions are not monophyletic. We here provide an updated phylogenetic hypothesis of the Abildgaardieae using nrDNA ITS sequences that continues to support the derivation of Nemum from within the Bulbostylis lineage. We make the nomenclatural combinations necessary to include Nemum in an expanded Bulbostylis, including seven new combinations and one new name. Further, we lectotypify two names and neotypify one
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