EFfects ob’ progressive edible le a f h nd tuber removal on yield and development of two d : j ..«. I J J purpose sweet pot a to (Ipomoea batatas (L.) Lam.) cultivars
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Date
1986
Authors
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Journal ISSN
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Publisher
Sokoine Univesirty of Agricuture
Abstract
Two dual purpose sweet potato (Ipomoea batatas (L)
Lain.) cultivars "Bangi" and "Simama" differing in shoot
morphology were subjected to differential leaf and tuber
harvest combination under field conditions at Morogoro.
The aim was to find out the effect of leaf and tuber
harvesting combinations on tuberous and edible leaf
yield, plant development and the adaptability of the
cultivars to two tuber harvesting methods.
Either
edible leaves, edible tubers or both leaves and tubers
were progressively removed.
The control treatment
consisted of a single final tuber harvesting without
leaf or tuber removal. Leaf and tuber harvesting
treatments were imposed monthly commencing at 77 and 99
days from planting respectively.
Sample plants for the
determination of dry matter distribution with time in
leaves, stems and roots were taken three times at
monthly intervals starting at 75 days from planting.
The erectophile cv '’Simama" gave a significantly
higher total yield (4.4 t/ha) and fresh edible leaves
(1.09 t/ha) over the procumbent cv '’Bangi”.
In cv
"Bangi'’ progressive removal of both leaves and tubers
gave 2.6 t/ha tubers above control and 0.6 t/ha above(iv)
control where only tubers were progressively harvested.
Progressive removal of leaves in cv "Bangi” had 2.4 t/ha
below control.
In cv "Simama” progressive harvesting of
both tubers and leaves gave 1.8 t/ha fresh tubers above
control and 1.5 t/ha above control where only tubers
were progressively removed.
Where only leaves were
progressively (harvested, tuber yields were 0.6 t/ha
above control.
Progressive harvesting of both tubers
and leaves yielded 3.1 t/ha fresh tubers more in cv
"Simama” than cv "Bangi" and 1.04 t/ha fresh edible
leaves.
P.emoval of leaves resulted in an increase of
6.9 t/ha fresh tubers and 1.4 t/ha edible leaves in cv
’’Simama’’ over cv ’’Bangi”.
In plants where only tubers
were removed cv "Simama” had 3.6 t/ha over cv ’’Bangi".
The progressive method of tuber harvesting had an overall
higher tuberous yield compared to single method but the
number of pig tubers was high.
During the first 10 weeks of growth, per cent dry
matter distribution in leaves was about 50 of the total
plant dry matter in all the treatments.
But 15 weeks
later dry matter in roots had increased to an average
of 34.1 per cent.
Nineteen weeks after planting the
proportion of dry matter in roots was significantly(V)
higher than that in leaves or stem.
Final dry matter
distribution in roots was higher in the treatments whose
tubers were harvested once in both cultivars.
Leaf
picking affected the performance of cv "Bangi" but not
cv "Simama”.
Combination of progressive removal of
both leaves and tubers gave highest fresh tuber yield
in both cultivars.
Sink rather than source seem to be
more important in sweet potato yield, but the
performance of the two cultivars showed that a good
source is also important.
Description
Dissertation
Keywords
EFfects ob’, progressive, edible le a f hnd, tuber removal, development, two d : j ..«. I J J purpose, sweet pot a, (Ipomoea batatas (L.), Lam.) cultivars