THE EFFECT OF TIME AND LEVEL OF DEFOLIATION ON THE GROWTH AND YIELD OF KENAF (Hibiscus cannabinus L.)
THE EFFECT OF TIME AND LEVEL OF DEFOLIATION ON THE GROWTH AND YIELD OF KENAF (Hibiscus cannabinus L.)
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Date
2001-12
Authors
JAPHET, Wisdom Sohunago
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Abstract
Field experiments were conducted at the research farm of the institute of agricultural research,
Samaru, Nigeria during the 1999 and 2000 wet seasons. The aim was to study the effect of time
and level of defoliation on the growth and yield of kenaf (Hibiscus cannabinus L.).
The treatments were time of defoliation (4,6,8, and 10 weeks after sowing (WAS)) and level of
defoliation (Control, leaves of the lower half removed, leaves of the upper half removed and
complete defoliation). The experiment was laid in a split-plot design with time of defoliation
allotted to the main plot while level of defoliation was allotted to the sub-plot.
The result indicated that defoliation at 4 weeks afler sowing reduced plant height, stem girth,
ribbon and stem dry weight while defoliation at 8 and 10 weeks afler sowing reduced the
number of pods per plant, pod diameter, number of seed per pod, and 100-seed weight.
Defoliation at 6 weeks after sowing did not adversely affect kenaf in this study but led to an
increase in plant height and number of seeds per pod.
The result also indicated that yield of kenaf was affected more by removing the upper leaves
than by removing the lower leaves showing that the upper leaves are more important to growth
and yield of kenaf than the lower leaves.
Time X level of defoliation interaction was significant for all the parameters studied except
number of days to 50% flowering. In both planting years and the combine analysis, removing
the upper or all the leaves of kenaf at 4 weeks after sowing adversely affected the growth and
development of kenaf. Similarly removing the upper or all the leaves of kenaf at 8 and 10
weeks after sowing adversely affected the pod and seed characteristics. Removing the lower
leaves at 6 weeks after sowing led to substantial increase in plant height, pod diameter, and
number of seeds per pod.
There was significant positive correlation between ribbon yield, plant height and stem girth in
this study. Seed yield also was positively correlated with number of pod per plant and number
of seed per pod.
Based on the above findings, it was concluded that defoliation at 4 weeks after sowing will
affect fibre yield of kenaf while defoliation at 8 and 10 weeks after sowing will affect seed yield
of kenaf. Defoliation at 6 weeks after sowing might be beneficial to kenaf. Removing all the
leaves or the upper leaf of kenaf will affect fibre and seed yield of kenaf.
Description
A thesis submitted to the post-graduate school, Ahmadu Bello
University, Zaria in partial fulfillment of the requirements for the
award of the degree of Master of Science in Botany
Department of Biological Sciences,
Ahmadu Bello University,
Zaria, Nigeria
Keywords
TIME AND LEVEL OF DEFOLIATION,, GROWTH AND YIELD,, KENAF (Hibiscus cannabinus L.)