| dc.description | Human nutrition is very essential in order to develop a nation in all respect.
Vegetables may play a vital role in this aspect. In the recent years, the value of
vegetables has been recognized as an important item of daily human diet all over
the world. They have been playing a very important role in our daily diet by
providing taste, palatability, variability and increase appetite. Generally vegetables
are rich sources of minerals, vitamins and essential amino acids. They are essential
for a balanced diet and neutralizing the acids produced during digestion of rich
foods (meats cheese and fatty foods). They are oouiiered as one of the most
important. groups of food crops having features of high nutritive value, labourintensive, relatively higher yield and higher fiscal gain. They are considered as a
cheap natural source of supplementary food and can be grown in a short duration.
Being labour intensive, vegetable production creates opportunities for employment. | en_US |
| dc.description.abstract | The performance of five winter vegetables was evaluated under four different
light levels i.e., 100, 75, 50 and 25 percent Photosynthetically Active Radiation
(PAR) at the experimental farm of the Bangabandhu Sheikh Mujibur Rahman
Agricultural University, Salna, Gazipur during November 1999 to March 2000.
Different light levels i.e., 75, 50 and 25 percent PAR were attained by using nets of
different pore sizes. Four winter vegetables i.e., cabbage, carrot, radish and tomato
were grown as in individual experiments following the RCBD design and three
varieties of eggplant i.e., Nayantara, Kajla and Uttara were grown separately in Split
Plot Design.
Plant height of all the five vegetables increased gradually with the decreased
of light level and significantly the longest plant was found under 25 percent PAR
level i.e. severe shade level. Other parameters of the tested vegetables varied
differentially due to variation of light levels.
In cabbage, outer leaf length increased gradually with the decreased of light
levels. Outer leaf breadth and yield contributing characteristics of cabbage i.e. head
length, head breadth and head fresh weight were increased progressively up to 50
percent reduction of light levels. Further reduction of light level, the above
parameters were drastically decreased. Fresh and dry yield (ton/ha) of cabbage
produced under 50 percent PAR level were numerically higher (29.98 and 1.90,
respectively) than those of yields obtained under full sunlight (28.92 and 1.72,
respectively) and 75 percent PAR (29.52 and 1.89, respectively).
In carrot, two parameters, i.e. plant height and leaf length were increased
with the decreased of light levels. But the other parameters showed the superior
performances under 25 percent reduced light level (75% PAR) and the least
performances under 25 percent PAR level. The highest yield (30.64 ton/ha) was
found under 75 percent PAR (25% reduced light) which was even statistically
higher than those of the yields obtained under full sunlight (100% PAR) and 50
percent PAR.
In radish, leaf length and leaf breadth increased gradually with the decreased
of light level. In case of number of leaves per plant and dry weight of leaves per
plant, the best performances were observed under 75 percent PAR level (25% shade
level) and the poorest performances were observed under 25 percent PAR level (75%
shade level). The values of the yield contributing characteristics such as radish length
and radish girth were found the highest under 75 percent PAR level. Similarly,
significantly the highest fresh yield of radish was found under 75 percent PAR level.
In tomato, some parameters such as number of primary branches, number
of fruit per cluster, fruit diameter, fruit weight were decreased with the decreased
of light levels, and other parameters such as number of leaves per plant, number of
cluster per plant, number of fruit per plant and yield were increased up to 25
percent reduction of PAR level. Further reduction of PAR level, these parameters
vi
were decreased gradually. The total yield of tomato obtained under full sunlight
(94.62 ton/ha), 25 percent reduced light (96.02 ton/ha) and 50 percent reduced
light (87.70 ton/ha) did not vary significantly but yield obtained under 75 percent
reduced light level decreased remarkably.
Among three varieties of eggplant, primary branches of Nayantara and
number of leaves per plant of all the varieties were the highest under 75 percent PAR
level. Fruit length and number of fruits per plant of all the three varieties were higher
under 100 percent PAR. Fruit diameter of Nayantara only and fruit weight of all the
varieties were higher under 75 percent PAR level. Fruit diameter of other two
varieties i.e. Kajla and Uttara were higher under 100 percent PAR. Yield (t/ha) of
eggplant irrespective of varieties were the highest under 100 percent PAR. However,
yields decreased gradually with decreased of light levels.
Relationship between light and yields of the studied vegetables were
estimated. In case of eggplant, linear relationship between fresh yield and percent
PAR was found, whereas in case of cabbage, carrot, radish and tomato quadratic
(polynomial) relationships were found.
From the above studies, it may be stated that the performances of different
winter vegetables under different light levels were different. But their degree of
adaptability to the different light levels ie., ability to grow under shade levels in
agroforestry system may be ranked as cabbage>carrot> tomato>radish>eggplant
(Kajla/Nayantara>Uttara). | en_US |
