Effect of Different Shade House on Quality Seedling Raising of High Value Vegetables

An experiment was undertaken to identify suitable shade house for different high value vegetables during the winter season of 2019-20 at the research farm of Olericulture Division, HRC, BARI, Gazipur. The experiment was randomized complete block design with 3 replications. Four vegetable varieties viz., tomato (V1), brinjal (V2), capsicum (V3), broccoli (V4) and 4 shading treatments [1) UV stabilized polyethylene film with 60 mesh insect net along with green shade net (T1); 2) UV stabilized polyethylene film with 60 mesh insect net (T2); 3) 60 mesh insect net (T3) and 4) Open field (control) (T4)] were included in this study. Different vegetables responded differently with the changes of shade house irrespective of different characters. Brinjal (V2) resulted in the maximum seed germination (93.58%) with the lowest mortality (5.58%), in case of shading treatment, UV stabilized polyethylene film with 60 mesh insect net along with green shade net (T1) exhibited the maximum seed germination (94.83%) with lower mortality (3.33%). In case of combined effect, maximum seed germination (93.58%) and the lowest mortality (2.08%) were observed in V2T1. The tallest seedlings were produced in V3T1 at every growth stage (15 days, 20 days, 25 days, 30 days). The maximum no. of leaves was produced in V3T2. The minimum insect infestation was observed in V1T1, V1T2, V2T1, V2T2, V3T1, V3T2, V4T1, V4T2 (0.67% at 15 days and 20 days).

vegetable production is much less than the requirement if balanced diet is provided to every individual. The present production of 4.3 million tones is to be raised to 13 million tones [1]. There are different ways and means to achieve this target, e.g., bringing additional area under vegetable crops, using hybrid seeds, use of improved agro-techniques. Another potential approach is perfection and promotion of protected cultivation of vegetables [2]. During rainy summer season, the temperature and solar radiations are adverse for growing off-season vegetables: tomato, capsicum, brinjal, cauliflower, broccoli, lettuce, cucumber, squash, netted melon, water melon. Hence, during extreme conditions of weather, these high value vegetables can be well cultivated under protected cultivation structures year-round. Research results have shown that by adopting protected cultivation, productivity of high value vegetable crops can be increased by 3 to 5 times as compared to open environment. Green house, polyhouse, shade net house & low tunnels are the different types of protected cultivation structures commonly adopted by the farmers of developed country.
Quality seedling production is a sector having recently started growing in Bangladesh. Cultivation from seedlings has many advantageous opportunities, such as earlier harvest, utilization of time, economization of land, energy, and seeds, healthy and homogenous production, and warning process for earliness.
In order to benefit from these advantages, producers have tended to production not from seeds, but from seedlings, thus increasing their demands for the seedlings of various vegetables. Cultivation from seedlings is much more important in congenial production. Use of vigorous seedlings provides solutions to the worrisome problems of the producers. In order to cultivate healthy seedlings, growing condition is as important as the ecological conditions. Various plant growing and dose studies are emphasized in the conducted researches. Efforts should be escalated for establishing and expanding growing condition, in compliance with the regulations on the production of quality vegetable seedlings, as being an important criterion. It is intended with this study to examine the quality features of the seedlings of the tomatoes and peppers, being produced in different growing conditions so as to be utilized in protected production to develop quality vegetable seedlings.
Shadenet house is a framed structure made of materials such as GI pipes, angle iron, wood or bamboo. It is covered with plastics nets which are made of 100% Polyethylene thread with specialized UV treatment having different shade percentages. It provides partially controlled atmosphere and environment by reducing light intensity and effective heat during day time to crops grown under it. Hence round the year seasonal and off-season cultivation is possible. Shading nets are used in tropical and subtropical countries for vegetable production [3] [4] [5]. Shading also reduces water requirements and increases irrigation water use efficiency in vegetable crops [6]. Poly house is a framed structure having 200 micron (800 gauges) UV stabilized transparent or translucent low density polyethylene which creates greenhouse effect making microclimate favorable for plant growth and development. Structure is large enough to permit a person to work inside. Poly film layer placed beneath shade net (around 1 m below shadenet) which increases the temperature during winter & reduces during the summer season. This structure also aims at protect crop from devastating rains.
Net house concept of protected house is a concept for protecting the insect. In well framed structure made up of GI pipes covered with 60 mesh nets.
To date, there is not much work available on protected cultivation of quality vegetables seedling production in Bangladesh condition. There is an urgent need to assess the quality vegetables seedling production and suitability for different vegetables under protected cultivation structures to meet the growing demand of the vegetables. Thus, the investigation was aimed to determine the efficacy of protected cultivation compared to open field on temperature and water requirement of vegetables during winter season. Since the selected crops viz., tomato, brinjal, capsicum, and broccoli are high value vegetables in Bangladesh that is why these vegetables are selected for these types of protected house to get quality seedlings. In this investigation an attempt is made to estimate the best protected cultivation structures for growing quality vegetables seedling production in Bangladesh condition. Keeping in view, the present study was formulated to select the suitable shade house for quality seedling raising of high value vegetables in Bangladesh.

Experimental Site
The experiment was designed at the research field of the Olericulture Division, HRC, BARI, Gazipur during November to December, 2019. The field was at 23.9920˚N Latitude and 90.4125˚E Longitudes having an elevation of 8.2 m from sea level under agro-ecological zone (AEZ) 28 (Annon, 1995). The farm was situated in the sub-tropical climatic zone and characterized by scanty rainfall during the experimental time.

Treatments and Raising of Plant Materials
Four vegetables varieties viz., tomato (V1), brinjal (V2), capsicum (V3), broccoli (V4) and 4 shading treatments [1) UV stabilized polyethylene film with 60 mesh insect net along with green shade net (T1); 2) UV stabilized polyethylene film with 60 mesh insect net (T2); 3) 60 mesh insect net (T3) and 4) Open field (control) (T4)] were included in this study. Total 16 treatment combinations were laid out in factorial design with three replications. Four types of vegetables were sown on polypot (12 cm × 10 cm) with fungicide treated seed on 15 November 2019 under four type of shading treatments. The polypots were filled up with fine sandy-loam soil and organic manure with 50:50 ratio. Different cultural operations such as irrigation, weeding, mulching etc. were done as and when needed.

Air Temperatures and Relative Humidity of the Experimental Area
Average monthly maximal and minimal air temperatures during the season in different structures are shown in Table 1 & Table 2. Table 1, while Table 3 shows the average relative humidity.  from 5 randomly selected seedling from each of replication.

Statistical Analysis
The recorded data for different characters were analyzed statistically using MSTAT-C program to find out the variation among the different genotypes by F-test. Treatment means were compared using Duncan's Multiple Range Test (DMRT) and standard error and coefficient of variation (CV %) were also estimated for each character.