نشریه روابط خاک و گیاه
پیاپی 43 (پاییز 1399)

Damask rose (Rosa damascene Mill) is one of the most important and economical rose species in Iran. After drought, salinity is the second most common environmental stress limiting agricultural production. In order to investigate the effect of salinity stress on Damask rose, an experiment was conducted based on a completely randomized design with three replications in the lysimeter condition at the Research Greenhouse of National Salinity Research Center during 2018-2019 growing season. The treatments were four levels of salinity stress (2.8, 5, 8 and 11 dS m‒1). The results indicated that the effect of different levels of salinity were significant for all traits except the number of branches per plant and the number of petals. The plants treated with the salinity levels of 2.8, 5 and 8 dS m‒1 had a significantly larger number of flowers per plant, flower weight, petal weight, yield flower and essential oil yield, compared to salinity level of 11 dS m‒1. Increasing the salinity level from 2.8 to 11 dS m‒1 caused the reduction in height (41.4%), 11 flowers per plant (47.8%), 0.77 g flower (39.9%), petal weight (18.3%), flower yield (62.4%), and essential oil yield (53.9%). Overall, the results showed that the salinity tolerance threshold of Damask rose of Mahalat was 8 dS m‒1.

Tomato leaf miner, Tuta absoluta Meyrick, is a pest which entered Iran in 2010; it was spread rapidly in many areas including Jiroft, in the southern Kerman province. The predatory bug, Nesidiocoris tenuis Reuter (Hempitera, Miridae) is an effective biocontrol agent against T. absoluta in tomato greenhouses. To evaluate the efficiency of N. tenuis in controlling T. absoluta, the predator was released in five treatments including: one pair of adult predator per plant, 6 fourth stage nymphs per plant in the same time with the artificial pest release, one pair of adult predator per plant and 6 fourth stage nymphs per plant one week before artificial pest release and control (no predator). The experiments were done in a completely randomized block design with 3 replications. Evaluation was done on 40 and 70 days after the artificial pest release on 20 plants per plot which had been selected randomly. The results showed that the two treatments of predator release before pest release were significantly better than the others in reducing the number of larvae (5 ± 1.52, 5.1 ± 1.01 on 40th day and 2 ± 0.58, 4 ± 0.58 on 70th day), mines (11.4 ± 2.96, 10.7 ± 2.2 on the 40th day and 4.67 ± 0.67, 6.7 ± 0.88 on 70th day) and the percent of the damaged fruit (4.7 ± 1.45 and 7.3 ± 1.21), as well as increasing the predator established on plants (3.6 ± 0.14, 3.1 ± 0.07 on the 40th day and 5.8 ± 0.2, 4.6 ± 0.24 on the 70th day). Moreover, these two mentioned treatments had no significant difference with the others in regard to the symptoms of N. tenuis damage in plants, especially in the final evaluation; so they could be recommended for use in commercial greenhouses.

Choosing the best covering material for the greenhouse roof is a very important factor influencing the quantity and quality of light entering the greenhouse. Some vegetative and reproductive traits and biochemical characteristics of two tomato cultivars (‘Synda’ and ‘Melody’) grown in some greenhouse units roof-covered with four covering materials (glass, plastic, polycarbonate and corrugated polyethylene) were investigated for autumn cultivation in the Research Greenhouses of Ferdowsi University of Mashhad. This experiment was designed in a split plot (main-plot: greenhouse cover; sub-plot: cultivar) based on a completely randomized design. The highest to lowest radiation rates were recorded in corrugated polyethylene, glass, plastic and polycarbonate covers, respectively. The ANOVA results showed that vegetative, reproductive and biochemical traits were significantly affected by greenhouse cover, cultivar, or greenhouse cover × cultivar interaction. Raising the plant health index through increasing the stem diameter and decreasing plant length was influenced by the amount of the irradiation provided by greenhouse covers; it was significantly higher in the corrugated polyethylene and glass covers rather than the plastic and polycarbonate ones. The maximum numbers of days from transplanting to flowering stage were obtained in the corrugated and glass covers (35.5 and 35 days, respectively) for the ‘Synda’ cultivar, and in glass cover (32.2 days) for the ‘Melody’ cultivar. The lowest fruit ripening (60 days) was observed in the ‘Melody’ cultivar under the corrugated polyethylene cover, while the highest value (80.25 days) was recorded in ‘Synda’ cultivar under the polycarbonate cover. Fruit production was the highest in the ‘Synda’ cultivar under corrugated polyethylene (6503.6 g/plant) and glass (6337.3 g/plant) covers, while ‘Melody’ under plastic and polycarbonate covers (1314.2 and 1027.1 g/plant, respectively) showed the lowest amount. According to the results of this experiment, from an economic point of view, based on Net Present Value (NPV) and Internal Rate of Return (IIR) factors, the greenhouse cultivation of ‘Synda’ cultivar under glass cover is recommended in Mashhad climatic conditions.

Cucumber root and crown rots are one of the main factors limiting cucumber production. Due to the soil borne nature of causal agents, their chemical control is not only ineffective, but also destroys the environment. Biological control strategies are one of the ways to combat these diseases. This research was conducted to study the biological control of cucumber soilborn diseases. The biocontrol influences of Trichoderma harzianum, T. virens, Pseudomonas fluorescens and Bacillus subtilis against cucumber root and crown rots caused by Fusarium oxysporum f.sp. radicis-cucumerinum, Pythium aphanidermatum and Phytophthora melonis were investigated in the laboratory. T. harzianum, which had the highest rate of the inhibitory growth in the laboratory, was used for the greenhouse studies. The disease severity and yield components of greenhouse cucumber Negin variety were evaluated in different treatments in a completely randomized design with four replicates using the SAS software. Highest percentage of inhibition in dual culture with 45.8% was observed by B. subtilis versus P. aphanidermatum. The results revealed that T. harzianum had the highest and lowest disease controls (32.8 and 18.8 percent) on F. oxysporum f.sp. radicis-cucumerinum and P. melonis, respectively. The treatment related to Trichoderma-inspired healthy plants had the greatest effect on the increase of the yield components in cucumber, while the infected plants with F. oxysporum f.sp. radicis-cucumerinum had the lowest yield. The disease severity index and root fresh weight showed a high correlation in different treatments. Therefore, fungal and bacterial antagonists were successful in controlling the cucumber root diseases.

Intercropping under microbial inoculation has been suggested as a method to improve the soil quality indices. The objective of this study was to evaluate the effect of microbial inoculation on some soil quality indices of moldavian balms- and bean-planted soils in sole cropping and intercropping. This experiment was carried out in the form of a factorial based on a randomized complete block design with three replications in greenhouse condition. Studied factors were microbial inoculation (AMF, PGPR, AMF+PGPR and without microbial inoculation) and planting patterns (sole cropping of moldavian balms and bean, 1 row moldavian balms + 1 row bean (1:1), 2 row moldavian balms + 2 row bean (2:2), 2 row moldavian balms + 1 row bean (2:1) and 1 row moldavian balms + 2 row bean (1:2)). At the end of the growth period, microbial respiration (BR), substrate-induced respiration (SIR), microbial biomass carbon (MBC), metabolic quotient (qCO2) and carbon availability index (CAI) in moldavian balms- and bean-planted soils were determined. The results showed that the intercropping patterns and microbial inoculation had a significant effect on all soil quality indices, in moldavian balms and bean plantation. The BR and SIR in the 2:1 intercropping moldavian balm under PGPR+AMF inoculation were measured to be 1.21 and 1.17 times higher than those of sole cropping, respectively. The 2:1 intercropping with PGPR+AMF inoculation increased MBC by 1.11 and 1.24 times, as compared to sole cropping of bean- and moldavian balm-planted soils, respectively. Different intercropping patterns and microbial inoculation increased soil CAI and decreased qCO2. In general, the application of intercropping and the potential use of microorganisms could improve the soil quality indices.

A greenhouse research was carried out to study the simultaneous effect of hydropriming and water stress on the yield and yield components of sweet pepper (Padra var.) in Ferdowsi University of Mashhad. The experiment was performed as a factorial arrangement of two factors in a completely randomized design with three replications. Hydro-priming consisted of two levels (non-hydropriming and hydropriming) and the water stress included three levels (100, 75 and 50 percent of water requirement), which were applied in a silty clay soil. The results showed that the effect of seed hydropriming on shoot fresh weight and electrical conductivity (EC) of fruit water were significant (P<0.01). The effects of deficit irrigation on the fruit fresh and dry weights, fruit number, plant height, and stem diameter were significant at 1 percent level (P<0.01), while the effects on shoot fresh and dry weights were significant at 5 percent level (P<0.05). Interaction effects of the treatments were significant on EC of fruit water at the 1 percent level (P<0.01), while the effects were significant on the fruit number, shoot dry weight, plant height, and pH of fruit water at the 5 percent level (P<0.05). The results also showed that the highest fruit number (4.34 per plant) was recorded in the 100 percent plant water requirement and seed hydropriming, while the lowest fruit number (2.0 per plant) was found in the 50 percent plant water requirement and seed hydropriming treatment. The highest and lowest fruit fresh weights (i.e., 191.4 and 82.1 g per plant) were observed in water stress treatments of 100 and 50 plant water requirement percent, respectively. The results also revealed that the fruit number changed in 75 and 50 percent water requirement treatments + non-hydropriming conditions by 11.3 and –11.0 percent, while under hydropriming conditions, fruit number was reduced by –16.5 and –50 percent, respectively. Overall, in this study the best treatment was 100 percent water requirements + seed hydropriming in greenhouses conditions. Deficit irrigation and hydropriming levels were applied on this plant in the Mashhad region in field conditions and recommended for future research.

Scale position and type of growing medium can affect the production of bulb in the lily plant. For this purpose, a factorial experiment was conducted based on a completely randomized design with two factors, scale position in two levels, outer and inner scales, in combination with growing media in five levels. Base or control treatment included 50% peat + 50% perlite; in the other four beds, 50% perlite was kept constant, but the peat fraction of the base bed was replaced with 15 or 30% compost or vermicompost of cow manure; the experiment was conducted with four replications. The results showed that the highest number of bulb (3), bulb diameter (12.79 mm) and bulb dry weight (0.25 g) were obtained in the combined treatment of 15% vermicompost and outer scales. The highest number of roots (5.61) was recorded in peat + perlite bed, and the highest leaf number (15.25) and bulb fresh weight (1.18 g) were observed in the 15% vermicompost treatment. Root length (8.55 cm) was the lowest in the 15% compost. The highest number of roots (4.96), root length (10.66 cm) and bulb fresh weight (1.19 g) were obtained in the outer scales. The total chlorophyll content of the plants produced in the treatment of outer scales in combination with control, vermicompost 15% and 30% and 15% compost showed no significant difference. The highest root diameter (1.56 mm), leaf length (14.5 cm) and nitrogen content (2.48%) were obtained in the outer scales and peat + perlite (control) treatment. The highest potassium concentration (4.91%) was obtained in the combined treatment of vermicompost 15% and outer scales. The lowest phosphorus concentration was observed in the combined treatment of 30% compost and inner scales. Therefore, the outer scales and low levels of vermicompost could be optimal for the lily bulb production.