Greenhouse Production
Mohammad Adibian; Yousef Hamidoghli; Mahmood Ghasemnezhad; Sasan Aliniaeifard
Abstract
Purpose: The use of supplementary light in regions with low natural sunlight is necessary to fulfill the increasing consumer requests for fresh vegetables. This study aimed to investigate the effect of different combinations of red and blue LEDs on yield and quality of greenhouse-grown sweet pepper (Capsicum ...
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Purpose: The use of supplementary light in regions with low natural sunlight is necessary to fulfill the increasing consumer requests for fresh vegetables. This study aimed to investigate the effect of different combinations of red and blue LEDs on yield and quality of greenhouse-grown sweet pepper (Capsicum annuum L.) fruits during the growth period. Research method: The experiments were conducted in Rasht, Iran as split plots in the form of a completely randomized design in three repetitions (four plants per plot) on two cultivars of sweet pepper (Padra and Shadlin). With the appearance of the first flower buds, plants were exposed to different light treatments including: three combinations of red (R) and blue (B) LEDs (T1:R8B1, T2:R7B2, and T3:R6B3), with a same intensity of 200 μmolm-2s-1 as supplement light to the natural light, together with natural light as control treatment (CT). Sweet pepper fruits were harvested weekly over 27 weeks and fruit yield and quality were assessed. Findings: Supplemental light using LEDs significantly increased yield and fruit quality parameters (except titratable acidity and maturity index) compared to the control. Marketable yield was differed among the light treatments and plants exposed to T3 showed the highest marketable yield (14.58 kg/m2). The effect of supplemental light on total yield was more detectable when the average daily light integral was the lowest (for example, the difference between T3 and the control treatment in January was 1.27 kg/m2, while this difference was 0.68 kg/m2 in June). No significant difference was observed between cultivars and T3 was the best treatment in most parameters. Research limitations: No limitations were found. Originality/Value: In the northern regions of Iran, even in the months that do not seem to have light limitations, the use of supplementary light is recommended to increase the yield of sweet peppers in the greenhouse.
Greenhouse Production
Nazila Khanbabaloo; Hanifeh Seyed hajizadeh; Farhad Behtash
Abstract
Todays, contamination of agricultural soils by different ways of salinity is increasing as a result of human and environmental factors that would reduce yield and quality of agricultural crops. However, there are some plants that can tolerate some degrees of salinity. Tomato is one of the horticultural ...
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Todays, contamination of agricultural soils by different ways of salinity is increasing as a result of human and environmental factors that would reduce yield and quality of agricultural crops. However, there are some plants that can tolerate some degrees of salinity. Tomato is one of the horticultural crops, moderately sensitive to salinity even that salinity can improve its quality. So, a study was conducted using four varieties of tomato under normal and salt stress (3, 6 and 9 dS m-1) hydroponic conditions to evaluate tomato quality. The results showed that increasing in salinity improves the quality and taste of tomato with a reduction in pericarp thickness, fresh weight and total protein. However, when the degree of salinity exceeds 6 dS m-1, a significant difference was observed in fruit yield which was variety dependent. Also, there is a significant difference between salt tolerance, performance, and taste of different varieties. Furthermore, it is found that the activity of guaiacol peroxidase and catalase enzymes increased as well as an increase in the level of salinity. Tomato cv. Super Chief with the highest number of fruits per plant, high level of proline as well as catalase activity, has the best performance against salinity levels of soil and was more resistant to salinity than other varieties. Also, tomato ‘Super Chief’ had the highest taste index with a slightly decline in the yield. Salt stress tomatoes have more carotenoid than controls but the level of 9 dS m-1 salinity was not tolerable by all varieties.
