Climate smart clove production for sustainable livelihoods: intervention for root knot nematode control
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Date
2021
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Publisher
Sokoine University of Agriculture
Abstract
Cloves is one of the important spices produced by small holder farmers in East Usambara
Mountain (EUM). Previously, the farmers in EUM reported wilting and drying of crops to
be associated with biotic and abiotic factors. Plant parasitic nematodes (PPN) particularly
root knot nematode has been reported to cause yield reduction in cloves and are
considered of highly economic importance. In the same area, climate smart agricultural
practices (CSA) had been introduced to enhance use of soil micro-organism such as
arbuscular mycorrhizal Fungi (AMF) to combat RKN. However the influence of CSA in
the association of RKN and AMF remains largely unknown. The aim was to evaluate the
association between indigenous AMF and plant parasitic nematode under CSA practices.
The first chapter of this dissertation contains general introduction, the second chapter
contains literature review describing cloves, PPN, AMF and Climate smart agricultural
practices, the third, fourth and fifth chapters comprise manuscripts in the
form of
publishable papers while the sixth chapter covers general conclusion
and
recommendation.
Chapter 3 reports on survey conducted in EUM to assess perception and awareness of
root knot nematode (RKN) among the farmers. The survey revealed that majority (89.1%)
of the farmers were not aware of RKN. Most of them practiced mixed cropping and
reported that they faced other constraints such insect pests and diseases that might have
contribute to wilting of their clove crop. In Chapter 4 abundance of AMF and plant
parasitic nematodes (PPN) in the clove fields was evaluated in CSA and NCSA. The
study revealed existence of mycorrhizal colonization in clove roots (86 to 100%) and that
Rotylenchulus spp. and Glomus spp. were the most abundant genera. There was no significant difference between PPN and AMF abundance under different farming
practices. However, there was positive association between AMF and PPN in both
farming practices. The studies showed that there was no significant association between
soil properties and arbuscular mycorrhizal fungi but there was positive association
between nitrogen and PPN abundance. There was no significant relationship between
AMF and PPN abundance in clove fields. In Chapter 5, Pathogenicity of RKN in clove
roots was studied. The findings showed that no observable galling symptoms were seen in
300 clove plants in EUM. Thus cloves were not affected by RKN. In screen house
experiments clove seedling
that were inoculated with second stage juvenile (J2)
nematode showed no galling symptoms and reproduction factor was less than 1 indicating
that clove plants were not hosts of root knot nematode. Thus RKN was not the cause of
the wilting of clove plants reported in the study area. Further research should focus on
other causes leading to the problem.
Description
Dissertation
Keywords
Climate, Smart clove production, Sustainable livelihoods, Root knot nematode control, Plant parasitic nematodes (PPN)