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Plant growth in a controlled environment system is highly dependent on the availability of light. The light-emitting diode (LED) is capable of providing the needed quality and quantity of light for the plant. The purpose of this study was to determine the effect of white LED light intensity on the growth of in vitro propagated apple (M-9) seedlings in a controlled environment system. Seedlings were grown for 30 days under five different white LED light intensities: 100–500 (L1), 250–500 (L2), 500–500 (L3), 250–250 (L4), and 100–100 (L5). Our findings indicate that seedlings treated with L3 grew substantially taller than seedlings treated with L1, L2, or L5. The number of leaves, stem diameter, shoot fresh weight, root fresh weight, and shoot dry weight of L3 treated seedlings were considerably greater than those growing in other treatments. Furthermore, root length, root dry weight, chlorophyll content, and photosynthesis rate were considerably increased in the L3 treatment group compared to the L5 treatment group. However, there was no significant difference in the stomatal conductance or transpiration rate of apple seedlings between the light treatments. Moreover, a positive correlation was seen between stomatal conductance and transpiration rate. These results suggest that light intensity PPFD 500-500 were favorable for the initial growth of in vitro propagated apple seedlings.

The production of horticultural crops in the outdoor environment facing various environmental factors, such as cyclones, droughts, heavy rain, and hailstorms, significantly affects the papaya production in the sub-tropical regions, especially in Bangladesh. Protected cultivation of horticultural crops is a common practice in developed countries. However, it is rarely observed in the developing countries, particularly for papaya production. Therefore, this study was carried out to find a protective approach to papaya cultivation to mitigate the environmental factors to obtain a quality yield. This production system consists of three treatments, including net house, poly shed house, UV poly shed house, and open field conditions (control). The results revealed that plants grown in the net house had significantly higher leaf number (30), fruit number (68), and fruit yield (56.28 kg/plant) than the control grown plant. Papaya cultured in the net house also showed significantly higher accumulation of chlorophyll, ascorbic acid, total phenol, reducing sugar, and β-carotene than those grown in other environments. In terms of peel color, papaya grown in the net house had the highest a* value (redness), whereas that grown in the open field had the lowest. Thus, the study demonstrated that papaya can be cultivated successfully in a net house with increased yield and phytochemical content. The findings provide a fundamental production strategy for quality papaya production in Bangladesh.

Irrational applications of insecticides on vegetable crops are very common in Bangladesh, resulting in harmful consequences for the environment and human health. Therefore, a study was conducted to evaluate the efficacy of biological and botanical insecticides on okra shoot and fruit borer grown in open fields. Four insecticides were used in this study, namely Bacillus thuringiensis (Bt), Spinosad 45 SC, Abamectin 1.8 EC, and Azadirachtin 1% EC an untreated control. The experiment used a randomized complete block design (RCBD) with three replications. The results showed that the rate of shoot infestation was the lowest in the Spinosad-treated plot (3.80%), and the highest was in the control (20.67%). The lowest fruit infestation (3.56%) was recorded in the treated plot of Spinosad. The rate of reduction of fruit infestation over control was 80.69, 60.14, 56.45, and 55.58% in the plots treated with Spinosad, Bt, Azadirachtin, and Abamectin, respectively. Consequently, the Spinosad-treated plot attained the highest yield (8.65 t ha−1), which was followed by the plots treated with Azadirachtin (6.74 t ha−1), Bt (6.28 t ha−1), and Abamectin (6.12 t ha−1). The highest net return and benefit–cost ratio (BCR) were 542.36 US$ and 2.64, obtained respectively from the Spinosad-treated plot. The second highest BCR (1.70) was obtained from the Azadiratin-treated plot, and the lowest BCR (1.18) was recorded in the Abamectin-treated plot. Therefore, the studied insect management practices could be incorporated to attain higher yields and economic benefits for growing okra in Bangladesh.

Seed priming is a technique that can potentially facilitate rapid and consistent germination and subsequent plant growth. The present study investigates the effect of different seed priming treatments and processing times on germination and growth efficiency for the effective cultivation of Yard-long bean. Thirteen different primings were used to determine the stimulatory effect on the germination and yield performance of the Yard-long bean. The priming treatments included control (without priming); hydro priming for 12, 18, 24, and 30 h; halo priming (1% CaCl2) for 12, 18, 24, and 30 h; and halo priming (2% KNO3) for 12, 18, 24, and 30 h. Studies showing the highest level of germination (86.66%), germination index (35.69), seedling vigor index (1833.80), number of branches (7.20), and pod yields per plant (1836.00 g) were recorded from halo priming with 1% CaCl2 at 12 h treatment. Halo priming with 1% CaCl2 at 12 h is thus considered to be a compatible priming technique for the germination of seeds and a higher yield of Yard-long bean.

This study was carried out to balance the production and consumption of assimilates according to crop conditions as a basis to reduce the waste of assimilation through leaf and fruit control. There were four treatments: one fruit and two leaves (F1L2); two fruits and two leaves (F2L2); two fruits and three leaves (F2L3); and two fruits and four leaves (F2L4). This study showed that, as the number of leaves increased in Periods 1 and 2, the stem diameter and average weight decreased, with F1L2 having the highest stem diameter and average weight, although its numbers of leaves and fruits were the fewest. In the summer, Period 3, F1L2 production was the lowest due to increased rates of flower drop and fruit drop. In Period 4, when ambient temperature and light levels were decreased, the number of fruits was increased. However, the production was decreased. F1L2 and F2L4 showed significant decreases in production. Although F1L2 showed the highest average weight, it had a low production due to a decrease in the number of fruits. F2L4 showed weak generative growth due to an imbalance in growth over the summer. After reaching the last stage of development, the number of leaves showed the highest average weight and production in F2L4. [ABSTRACT FROM AUTHOR]

Irrational applications of insecticides on vegetable crops are very common in Bangladesh, resulting in harmful consequences for the environment and human health. Therefore, a study was conducted to evaluate the efficacy of biological and botanical insecticides on okra shoot and fruit borer grown in open fields. Four insecticides were used in this study, namely Bacillus thuringiensis (Bt), Spinosad 45 SC, Abamectin 1.8 EC, and Azadirachtin 1% EC an untreated control. The experiment used a randomized complete block design (RCBD) with three replications. The results showed that the rate of shoot infestation was the lowest in the Spinosad-treated plot (3.80%), and the highest was in the control (20.67%). The lowest fruit infestation (3.56%) was recorded in the treated plot of Spinosad. The rate of reduction of fruit infestation over control was 80.69, 60.14, 56.45, and 55.58% in the plots treated with Spinosad, Bt, Azadirachtin, and Abamectin, respectively. Consequently, the Spinosad-treated plot attained the highest yield (8.65 t ha-1, Bt (6.28 t ha-1 and Abamectin (6.12 t ha-1). The highest net return and benefit--cost ratio (BCR) were 542.36 US$ and 2.64, obtained respectively from the Spinosad-treated plot. The second highest BCR (1.70) was obtained from the Azadiratin-treated plot, and the lowest BCR (1.18) was recorded in the Abamectin-treated plot. Therefore, the studied insect management practices could be incorporated to attain higher yields and economic benefits for growing okra in Bangladesh. [ABSTRACT FROM AUTHOR]

Seed priming is a technique that can potentially facilitate rapid and consistent germination and subsequent plant growth. The present study investigates the effect of different seed priming treatments and processing times on germination and growth efficiency for the effective cultivation of Yard-long bean. Thirteen different primings were used to determine the stimulatory effect on the germination and yield performance of the Yard-long bean. The priming treatments included control (without priming); hydro priming for 12,18, 24, and 30 h; halo priming (1% CaCl2) for 12, 18,24, and 30 h; and halo priming (2% KNO3) for 12,18,24, and 30 h. Studies showing the highest level of germination (86.66%), germination index (35.69), seedling vigor index (1833.80), number of branches (7.20), and pod yields per plant (1836.00 g) were recorded from halo priming with 1% CaCl2 at 12 h treatment. Halo priming with 1% CaCl2 at 12 h is thus considered to be a compatible priming technique for the germination of seeds and a higher yield of Yard-long bean. [ABSTRACT FROM AUTHOR]