The effect of nitrogen application and deflowering on vegetative growth, yield and quality; and postharvest storage stability
Abstract
Two experiments were cond~c~ed between August, 1990
and April, 1991, at the Faculty of Agriculture Field
Station, Kabete Campus, Universi~y of Nairobi to study the
effects of nitrogen rates (0, :"3, 26 and 52 kgN/ha) and
deflowering on vegetative growth, leaf yield and quality
of Gynandropsis gynandra L. The experiments were setup in
a randomized complete block design with eight factorial
treatments and three replications. Quality of the leaves
was evaluated by analysing for ascorbic acid, ~-carotene
and total phenolics contents. Storage stability of the
leaves was evaluated under two storage conditions (shelf
and refrigerated) and two packaging methods (perforated
and non-perforated polythene bags) by analysing for losses
in ascorbic acid and moisture and colour change over time
of storage.
.s Plants top-dressed with N and deflowered had
increased vegetative growth and significantly higher mean
weekly and cumulative leaf yields. Nitrogen application
also tended to extend the harvest duration. Increasing N
rate significantly decreased the content of ascorbic acid
in leaves, although the leaves generally had high contents
on dry matter basis. Deflowering, and the two-way
interactions between N, deflowering and plant age had
significant effects on ascorbic acid contents in the
leaves during the second experiment. Nitrogen application
.ocfo
a~d deflowering had no significant effects on ~he contents
of B-carotene and total phenolics in the leaves. The
contents of ascrobic acid, B-carotene and total phenolics
were significantly affected by plant age. The content of
ascorbic acid increased with plant age whereas that of
total phenolics decreased. The content of B-carotene was
highest at the 7th week of growth after which it
decreased.
The non-perforated polythene bags showed effective
control of moisture loss from leaves despite the storage
condition, and made the leaves retain ascrobic acid
better than the perforated ones. Temperature had a
dominant effect on colour deterioration with refrigerator
condition having very slow deterioration. Shelf storage
could be effective for storage upto 2 days and
refrigerator up to 12 days.
Citation
Maumba, M. K(1993). The effect of nitrogen application and deflowering on vegetative growth, yield and quality; and postharvest storage stabilitySponsorhip
University of NairobiPublisher
Department of Plant Science and Crop Protection, University of Nairobi
Subject
Nitrogen applicationDeflowering
Vegetative growth
Vegetative Yield
Vegetative Quality
Postharvest Storage
Description
Msc Thesis