EFFECT OF SEED SIZE AND PHOSPHORUS LEVELS ON THE GROWTH AND YIELD OF COWPEA (Vigna unguiculata [L] walp) VARIETIES
EFFECT OF SEED SIZE AND PHOSPHORUS LEVELS ON THE GROWTH AND YIELD OF COWPEA (Vigna unguiculata [L] walp) VARIETIES
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Date
1990-11
Authors
TANKO, MUSA UMAR
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Abstract
This experiment was conducted during the rainy season
of 1989 in Samaru in Northern guinea Savanna to investigate
the effect(s) of seed size and phosphorus levels on the
yield and yield components of cowpea [Vlgna unguicutata [L.]
Walp) varieties. Treatments consisted of two cowpea varieties
(improved local S.L 1696 and improved Sampea-7), three seed
sizes (large, medium and small) and three phosphorus level
(0, 37.5 and 75.0kg P20c/ha). Possible combination of all
the treatments were laid in a split-plot design and
replicated three times.
The investigation showed that while large sized seeds
produced slightly higher yield and yield components than the
remaining two seed sizes, large seed size irrespective of
the variety planted produced significantly plants with
longer vines, wider leaf area, heavier dry shoot, heavier
dry leaf; more leaves all at 4 WAP and more branches at: 8
WAP than the small seed size.
Application of phosphorus slightly decreased the yield
and yield components, although these reductions were not
statistically significant. Crude protein content of the
seed however increased with application of phosphorus (P)
fertilizer.
Improved local S.L 1696 variety was more vigorous in
vegetative growth than Sampea-7. This variety (Sampea-7)
on the other hand significantly produced higher grain yield
(2.62 tons ha"1) than improved local S.L 1696 (1.5 tons ha" ).
Interactive effect of seed size and cowpea variety significantly
influenced number of leaves at 4 WAP; branches at 8
and 10 WAP and 100-seed weight at harvest. Improved local
S.L 1696 variety irrespective of seed size produced
significantly higher number of leaves; and 100-seed weight
than Sampea-7.
Grain yield was significantly and positively correlated
with yield components (number of flowers, pods, seeds and
seed weight per plant) and vegetative growth characters
(plant height and leaf area per plant).
From these findings, it can be concluded that grain
yield increased by 9.4% when large rather than small seeds
were sown. There is therefore no significant yield
advantage in selecting large seeds for planting.
Yield and yield components decreased slightly with
P-levels, the residual P in the soil as evident from the
soil test results, was more than sufficient to raise a good
crop of cowpea without P-fertilization. It is therefore
a waste of time and resources applying P-fertilizer where
soil test results prior to planting reveal high level of
residual-P.
Description
A Thesis submitted to the Postgraduate School, Ahmadu Bello
University, in partial fulfilment of the requirements of
the Degree of Master of Science in Agronomy.
DEPARTMENT OF AGRONOMY
Faculty of Agriculture
Ahmadu Bello University, Zaria
Nigeria
NOVEMBER 1990
Keywords
SEED SIZE,, PHOSPHORUS LEVELS,, (Vigna unguiculata [L] walp),, VARIETIES