نشریه علوم سبزی ها
سال سوم شماره 1 (پیاپی 5، بهار و تابستان 1398)

In order to study the effects of foliar application of naphthalene acetic acid (NAA) on growth, yield and fruit quality of sweet pepper "California Wonder", an experiment was conducted in a randomized complete block design with three replications in the Research field of Faculty of Agriculture (University of Zanjan, Iran) in 2016. Treatments were consisted of NAA at five levels of 0 (control), 50, 100, 150 and 200 mg.L-1. The results showed that foliar application of NAA had significant effects on vegetative traits, yield and its components, and fruit quality. The highest fruit number per plant (5.6 and 6) and yield (24.6 and 24.9 t.ha-1) was achieved at 50 and 100 mg.L-1 NAA. The maximum plant height and chlorophyll index were obtained by application of 100 and 150 mg.L-1 NAA. The highest amount of total soluble solid (4.93 °B), vitamin C (103.73 mg.100ml-1) and fruit firmness was recorded at 100 mg.L-1 NAA. According to the results, application of 100 mg.L-1 NAA can be proposed to improve yield and fruit quality of sweet pepper.

Light intensity is one of the most important environmental factors affecting the growth, yield and quality of fruits and vegetables. Salicylic Acid (SA) alleviates the negative effect of high and low light intensity. In order to evaluate the effect of interaction between light intensity and SA  on physiological properties, yield and fruit quality of tomato (Solanum lycopersicum L. cv. Super Beta F1), a split plot based on randomized complete block design experiment with three replications was carried out at Moghan College of Agriculture and Natural Resources located in Ardabil province, Iran in 2015. The treatment were included differentlight intensity levels (100, 75 and 50% light intensity) and SA (0 and 2 mM). Results revealed that the plant fresh and dry weight was decreased significantly with decreasing light intensity, especially without SA treatment. The leaf stomatal conductance and Fv/Fm ratio were increased with decreasing light intensity. The application of SA improved leaf stomatal conductance and Fv/Fm ratio. The application of SA caused increase in truss number and fruit number per truss under different light intensity levels. Tomato yield in full light intensity treatment and treated with SA was 116% higher than tomatoes yield grown in 50% light intensity and without treatment with SA. The highest and lowest value of total soluble solid, fruit firmness, EC and pH of fruit juice were obtained in full light intensity and 50% light intensity, respectively. In general, it is concluded that tomatoes grown in full light intensity has better yield and quality. SA application improves the quantitative and qualitative properties of tomato in different light intensities.

In order to investigate the effect of glycine- betaine (GB) and intermittent warming (IW). On shelf life and quality of sweet pepper fruits an experiment was conducted as a factorial based on complete randomized design in University of Zanjan in 2016. Treatments were consisted of intermittent warming at three levels (control, 20 and 30 ºC) and glycine- betaine at three levels (0, 5 and 10 mM). The fruits were stored at 4 °C and 85±5% RH for 30 days. The results showed that the amount of vitamin C, chlorophyll, carotenoids content and peroxidase activity in the fruits were decreased and fruit weight loss percentages, extract pH and electrolyte leakage were increased during storage at low temperature (4 °C) by gradually increasing of storage time. Intermittent warming and glycine betaine had positive effects on studied traits such as soluble solids, extract pH, vitamin C, chlorophyll, carotenoids content and peroxidase activity and improved the quality of pepper fruit during storage at low temperatures. These treatments prevented weight loss and electrolyte leakage during the storage. The intermittent warming between temperatures of 20 °C and 5 mM of GB were found to be more beneficial in improving the qualitative characteristics of pepper fruits. Therefore, the use of glycine betaine and intermittent warming can increase quality of sweet pepper, and by preventing the increase of contamination, can be improved the shelf life of sweet pepper.

The aim of the present investigation was to evaluate the effect of vermicompost and putrescine on morphological characteristics, photosynthetic pigments and yield of cucumber (Cucumis sativus L. var. Yalda). The experiment was conducted as a factorial experiment in completely randomized design with three replications at the research greenhouse of the University of Mohaghegh Ardabili, Iran. The treatments were consisted of vermicompost (0, 20, 40 and 60 volume percent) and putrescine (0, 0.5, 1 and 1.5 mM). Results showed that application of putrescine and vermicompost simultaneously improved plant height, leaf area and shoot dry weight of cucumber. The highest yield (2760 gr/plant) was achieved by application of 40% vermicompost and 0.5 mM putrescine solution. The lowest yield (698 gr/plant) was also achieved by application of 60% vermicompost without putrescine. Application of putrescine without vermicompost caused increased in the pigments in most of the treatments. However, putrescine with vermicompost had different results. Application of 20% vermicompost in the bedding had the greatest effect on the increase of photosynthetic pigments (chlorophyll a, total chlorophyll and carotenoids). Application of vermicompost without putrescine caused reduction in the photosynthetic pigments. Adding 40 and 60% vermicompost to the sowing bed resulted in an increase in the amount of chlorophyll b compared with the control.. In general the results of this investigation showed that integrative application of vermicompost upto 40% with spraying 0.5 mM putrescine can be effective for greenhouse cucumber production.

The aim of this was to investigate the effect of high and low temperature stress on growth, photosynthesis and antioxidant changes in vegetative growth stage of tomato. Tomato plants which were grown in hydroponics system exposed to temperature stress at 40 ºC and 10 ºC compared with plants grown in the greenhouse at optimum temperature of 25±2 as control. All plants were transfer to optimum condition in the greenhouse after stress treatments and growth parameters were measured after 10 days. The results of the comparison between these three temperatures showed that the highest fresh weight of shoot was observed at control treatment. In high temperature stress conditions observed 56.7% decrease fresh weight compared to control treatment and in low temperature stress conditions observed 65.3 decrease. Similarly, fresh weight of root was highest in control treatment and heat stress 45% and low temperature stress 64.6% showed decrease compared to optimum temperature conditions. Root volume was reduced by temperature stress significantly and photosynthesis rate was the highest in control treatment and lowest under high temperature stress. In general, it can be stated that temperature stress in this study affected growth and photosynthetic traits more than antioxidant traits.

In recent years, the production of greenhouse vegetables in Iran, has grown steadily due to water resources constraints. Among all the provinces of Iran, south of Kerman province, has been assigned the second place of cultivation area and production of greenhouse vegetables. Considering this importance, it has been tried to study the current status of greenhouse vegetables (cucumber and tomato) as well as problems of the producers in this area, in the present study. The research was based on descriptive and survey method. The statistical population was 1629 greenhouse vegetables producers with a license started during 2016-17 among which 88 producers were selected using Cochran formula and stratified cluster sampling method. The evaluation tool was a questionnaire that its validity was confirmed by a panel of experts and its reliability for different parts of the questionnaire was obtained between 0.63 to 0.89 using Cronbach's alpha coefficient. Garrett ranking technique was used to achieve the research objectives. The descriptive results of the study showed that, price fluctuations, lack of proper sales market and intermediation, respectively were the most important problems and barriers in the south of Kerman province. Therefore, in order to promote the production of these vegetables, it is suggested to address the marketing problems and lack of financial resources of the producers, instead of emphasizing on the technical aspects of production.