Methods for extracting plant pathogenic nematodes from Brachiaria seed
ABSTRACT A commonly used forage grass in Brazil is Brachiaria spp. These grasses are used as feed for beef and cattle production and are grown on approximately 70 million hectares in Brazil. A pasture with Brachiaria spp. can last for 20 years and is relatively free from diseases. Two of the p...
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| Formato: | Second cycle, A2E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2015
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/8453/ |
| Sumario: | ABSTRACT
A commonly used forage grass in Brazil is Brachiaria spp. These grasses are used
as feed for beef and cattle production and are grown on approximately 70 million
hectares in Brazil. A pasture with Brachiaria spp. can last for 20 years and is relatively
free from diseases. Two of the pathogens that do attack Brachiaria spp. are
the nematodes Aphelenchoides besseyi and Ditylenchus dipsaci. These nematodes
are seed-borne and affect the host plant by eating of the plants growing parts of
stems and leaves. As the plant matures, the nematodes move to the seeds where
they overwinter or stay until the seeds get in contact with moisture. Both A. besseyi
and D. dipsaci can survive in the seeds in a dry state for several years. Both of these
nematodes are classified as quarantine pests due to the damage they cause on their
host plants and economically. To stop the spreading of A. besseyi and D. dipsaci,
chemical or hot water treatments are used to control the nematodes. In Sweden, a
company called Incotec Sweden AB has developed a method for treating seedborne
diseases, named ThermoSeed. This treats the seeds with different intensities
of steam. To evaluate their treatment, a method to extract nematodes from Brachiaria
seed is needed to be able to guarantee seeds without living nematodes. The
purpose of this master thesis was to find a method for extracting nematodes from
Brachiaria ruzizensis seed that is fast, reliable and cost effective. Four different
methods were tested: the Baermann funnel method, a method developed by Zuckermann
et al., a method developed by Coolen and D’Herde and The simple method
developed by Hoshino and Togashi. To test the methods, three types of treated
seeds were used. Untreated seed (positive control), treated seeds with Incotec
treatment and negative control (seeds that have been treated multiple times with
high steam intensity). The methods were analyzed by counting the recovered nematodes
from each of the methods. The data collected were analyzed statistically with
ANOVA and a following post hoc Tukey test. From these analyses it was concluded
that the Baermann funnel was the method which extracted the most nematodes
from the untreated seeds compared to the other methods. The Baermann funnel
method also gave clear samples and was easy to conduct. |
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