On-Station and On-Farm Evaluation of Sweet Pepper ( Capsicum annuum Capsicum annuum L.) in Sylhet

ABSTRACT


INTRODUCTION
Sweet pepper (Capsicum annuumL.) is an important vegetable crops cultivated extensively throughout the world especially in the temperate countries. It is a flowering plant under the genus Capsicum and belongs to the family Solanaceae. Tropical South America, especially Brazil is the original home of pepper (Shoemaker & Teskey, 1995). Sweet pepper fruits are mainly eaten as cooked or raw as well as sliced in salad and fruits are harvested either at green mature stage or at coloring stage (Singh et al., 2011). Besides vitamins A and C, the fruits contain mixtures of antioxidants, carotenoids, ascorbic acid, flavonoids and polyphenols (Nadeem et al., 2011). It is also rich in capsaicin that may help works against inflammation (Knott & Deanon, 1967). Although sweet pepper is the most important summer crop of temperate regions, but efforts are being made recently to grow in Bangladesh (Paul, 2009). Some advanced farmer's grow sweet pepper sporadically in Bangladesh to meet the demand of big cities and earned very high price (Saha & Salam, 2004). But there are several problems associated with its production. First of all, low night temperature was found to have a negative effect on the production of this crop (Anon, 2008). The optimum temperature requirement for sweet pepper cultivation ranged from 16-25 0 C while night temperature below 16°C and day temperature above 32°C causes blossom dropping (Boswell, 1964). In Bangladesh, night temperature is gradually decreased below 10 0 C from December to January which is the optimum time for vegetative growth and fruit setting of sweet pepper (Halim & Islam, 2013). In that situation, vegetative and reproductive growth of sweet pepper plants become stunted and flower and fruit drops occur. Secondly, different types of mites were found important pests of sweet pepper (Weintraub, 2007). They possess needlelike chelicerae which pierce plant parts, often feeding on the undersurface of the leaf (Zhang, 2003). Some of them produce silk webbing which covers the leaf surface resulting reduced photosynthesis and eventually causes leaves to dry and drop off, while some other causes leaf edges become rigid and roll under (Weintraub, 2007). It is relatively serious pest for low tolerant species since less than five mites on a young sweet pepper plant can cause severe damage by reducing fruit number per plant as well and fruit weight (Cho et al., 1996). They can easily move https://journals.e-palli.com/home/index.php/ajaset Am. J. Agric. Sci. Eng. Technol. 6(3) [83][84][85][86][87]2022 from infested plant to clean ones by farm workers or by whiteflies (Palevsky et al., 2001). Once they get entry into a cultivated area it can spread rapidly and have severe economic impact. Sylhet is considered as a special agricultural zone in Bangladesh. Prevailing night low temperature is a limiting factor for growing sweet pepper in hilly areas of Sylhet. Therefore, to make its cultivation successful, polyhouses, poly-tunels and plastic mulching are most effective solutions (Chandra et al., 2000 andSingh et al., 2010). Night temperature under poly covers reported higher than the outside (Halim & Islam, 2013). Again these structures also facilitate a longer duration use of nutrient elements from the soil by crop plant (Singh et al., 2003). Very limited information is available for growing sweet pepper under protected structures under Sylhet condition. So, the effectiveness of protective structures in Sylhet need to be addressed. Moreover, poor farmer sometime prefer to cultivate sweet pepper under open field condition considering the high price of the protective structures. They often harvest a lower yield due to severe mite infestation. No data regarding miticides application and their effect on yield was reported previously in this region. So, effectiveness of miticides on controlling of mites and yield performance of sweet pepper also need to be studied. Therefore, this study mainly focused on(a) on-station evaluation of a sweet pepper hybrid under different protective structures and miticides application, and (b) on-farm evaluation of another sweet pepper hybrid to the farmers field of Moulvibazar and Sunamganj district of Sylhet division under Net+polythene protective structure only.

MATERIALS AND METHODS
The on-station evaluation of sweet pepper was done at the Horticulture Research Field of Sylhet Agricultural University, during October 2015 to March 2016. A sweet pepper variety' California Wonder' was evaluated under two different protective structures(T1 = only Net and T2 = Net + polythene), open field with two different miticides application (T3 = Intrepid and T4 = Vertimec) and open field without miticide (T5 = Control). The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. For both net and net + polythene protected structures, the height of the structure was 1.0 meter above soil surface. White colored polythene of 0.5mm thickness and 120 mesh white nylon net were used for to place over the structure for covering the plants. For miticides application, a hand sprayer has been used and sprayed @ 2 ml/L of water in the late afternoon at each seven days interval from transplanting until last harvesting. The seeds were sown in seedbed on 28 th October 2015. Thirty days old and healthy seedlings were finally transferred to the experimental field. The unit plot size was 3.2 × 1.0 m and the plants were spaced 60 × 40 cm between plant-to-plant and row-to-row, respectively. Intercultural operations such as watering, weeding, gap filling, earthing up etc. were done as and when necessary. A recommended fertilizer dose with cowdung, urea, TSP, MP, gypsum and ZnO@5 t/ha, 217 kg/ha, 333 kg/ha, 200 kg/ha, 111 kg/ ha and 5 kg/ha, respectively was applied (Saha, 2001). Harvesting of the green fruits was done when they were relatively firm and crispy (Shoemaker and Tesky, 1995). Data were collected on growth, yield and yield related parameters and the collected data were statistically analyzed with the help of MSTAT-C software. Cost of cultivation (Tk/decimal), gross return (Tk/decimal), gross margin (Tk/decimal) and BCR were also calculated. The on-farm evaluation of sweet pepper was done at the farmer's field of Moulvibazar and Sunamganj districts during the same period as of the on-station study. Four progressive farmers from each district were selected with the help of Upazila Agriculture Officer. In this experiment, the genotype 'BARI Mistimorich-1' was evaluated under net + polythene protective structure only and height of the structure was 1.0 meter above the soil surface. Each farmer was used a land area exactly one decimal (40.46 sq m). Healthy and uniform seedlings of 30 days old were transplanted in the main field maintaining a spacing of 60 cm × 40 cm. Fertilization and intercultural operations were done as of the on-station study. The plants were remained under net protection for whole cropping period while polythene cover was given only two coldest months of December and January.
Harvesting was done at mature green stage both in Moulvibazar and Sunamgang districts. Data were collected on different parameters such as days to first flower, number of fruits per plant, fruit yield per plant etc. Simple statistical parameters like mean and standard deviation were measured for interpretation of the results. Economic analysis was also made for this experiment. Two different variety of sweet pepper were used for onstation and on-farm study mainly due to the availability of seed materials. Moreover, average yield performance of California Wonder and BARI Mistimorich-1 (21.31 and 20.38 t/ha, respectively) are more or less similar in Bangladesh condition as previously observed by Akther (2015) under different net protective structures.

RESULTS AND DISCUSSION On-station evaluation of sweet pepper in Sylhet
Significant variation was observed among the treatments for all the parameters observed in this experiment (  Halim and Islam, 2013.They also reported that the low night temperature along with other biotic and abiotic stresses in the open field might play a significant role for low plant growth. Boswell (1964) reported that low night temperature is very detrimental for growth of sweet pepper. The congenial atmosphere prevailed in both the protective structures in this experiment encouraged the plants for more vegetative growth, therefore, longer and similar harvesting duration of fruits (34.33 days) in comparison to other treatments. The highest number of fruits per plant was recorded from the net + polythene protected structure (11.57) followed by only net protected structure (10.53). No differences in case of fruits number per plant was observed among Intrepid, Vertimec and open field treated plants. Individual fruit weight, fruit length and fruit diameter were the highest and statistically similar for both net and net + polythene protected structures. Among five different treatments the maximum fruit yield per plant was obtained when plants were grown under net + polythene protected structure (893.90 g), followed by only net protected structure (801.00 g). While the fruit yield per plant was minimum in open field condition (358.20 g) which was statistically similar to Vertimec treated plants (375.01 g). Similar result has previously been observed by Sayed (2016). Islam and Halim (2014) obtained the lowest fruit yield per plant under open field condition while it was the highest under tunnel cover with polythene and nylon net. Result indicated that in open field condition (with or without miticides application) having various biotic and abiotic stresses, therefore, plants produced the lowest yield. Fruit yield was maximum (178.78 kg/decimal) under net + polythene protected structure, followed by only net protected structure (160.20 kg/decimal). The lowest yield (71.68 kg/decimal) was obtained from open field condition. This variation in fruit yield might be attributed due to shade-nets provide physical protection against hail, wind, bird and insect-transmitted virus diseases (Shahak, 2006). Ahemd et al. (2016) opined that reducing the transmitted solar radiation under different protective structures reduce the canopy and air temperatures as well as the transpiration rate. This consequently enhances the water use efficiency and increases the crop productivity up to 40%. Table 2 sowing the benefit cost ratio analysis of sweet pepper grown under protective structures and open field with and without miticides application. Plants grown under net + polythene protected system incurred the highest total cost compared to other treatments. The lowest total cost was required for open field cultivation. Cost analysis showed that plants grown in net + polythene protected structure gave the highest gross return followed by only net protective structure. Gross margin and BCR were also the highest in net + polythene protective structures closely followed by only net protective structure. Considering the open field with and without miticides application, the maximum BCR (4.0) was obtained from Intrepid treated field. The lowest BCR was recorded from open field condition which was less than half of the BCR of both net and net + polythene protected structures. Similar result in terms of BCR was reported earlier when crops were grown under different protective structure compared to open field (Singh et al, 2011).

Comparative study between Moulvibazar and Sunamganj District
Comparison between two districts for sweet pepper yield and economic profitability is presented in