مجله علوم و فنون باغبانی ایران
سال بیست و دوم شماره 1 (بهار 1400)

The use of bio-fertilizers plays a key role in production of organic crops. In order to evaluate the effect of biological and chemical fertilizers on growth, yield and quality of muskmelon (Cucumis melo L. cv. Ahlam) fruit under drought stress condition, the experiment was performed with the use of factorial split in block completely randomized design in three replicates. In this study treatments included drought stress, bio and chemical fertilizers. Drought stress was applied in three levels: 100, 75 and 50% of field capacity; (FC) the fertilizers (NPK) were applied in four levels (0, 60, 120 and 180 Kg h-1), Nitroxin was used in two levels of control (no consumption) and 100% application. The results revealed that the presence of the drought stress and fertilizer type had a significant effect on the yield components and quality of muskmelon fruit. Fruit firmness, TSS and vitamin c content showed the direct relation with the reduction of plant water requirement. On the other hand, the total phenol content was increased with the consumption of nitroxin and 60 kg/h chemical fertilizer. Additionally, application of nitroxin with the 180 kg/h chemical fertilizer showed the highest a*and b* color values in pulp and peel of fruit under 50% of F.C. In general, biofertilizers can be replaced with chemical ones, alleviated drought stress damages and improved fruit quality.

Effect of foliar application with nitrogen, boron, zinc, and summer pruning on fruit set and fruit quality and quantity of grape (Vitis vinifera cv. Siah Shahani) in Pasargad, Fars’s province. The highest leaf length (22.3 cm) was observed in the control treatment and green pruning. The leaf width (11.1 cm) were observed in the nitrogen treatment. The combination of zinc and green pruning created the longest cluster length (33.9 cm) and the combination of zinc + nitrogen + boron and green pruning created the highest number of berries (170). The interaction of zinc + nitrogen and green pruning and green pruning, respectively, caused the highest number of berries (217.2) and the volume of berries (119 ml). The highest number of seeds (55.5) was related to the treatment of nitrogen + boron and green pruning combination. The highest wet weight (1.7 g) and seed size (4.98 mm) were observed in the treatment of boron. Most chlorophyll (34 mg g-1 dry weight) was observed in the zn and boron spray treatment. The use of fertilizer treatments did not have a significant effect on pH and TSS, but the use of nitrogen + boron and green pruning significantly increased vitamin C levels compared to control.

In order to evaluate drought tolerance of four clonal rootstocks of Prunus an experiment was conducted in a completely randomized design with two factors. The first factor was four rootstocks including Cadaman, Myrobalan 29c, GF677, and GN15 and the second factor contained three levels of drought stress, including 100, 75, and 50% of field capacity. Height, leaf number and crown diameter were recorded during the treatments, whereas leaf relative water content, chlorophyll and carotenoids contents were measured at the end of the experiment. Fresh and dry weight of leaves and roots decreased for all rootstocks by applying drought stress. Leaf number of GF677 decreased under drought conditions, compared with the control, while its reduction was not significant for other rootstocks. The height of Myrobalan 29c plants was more affected by drought compared with the other rootstocks. Moreover, carotenoids decreased more for Cadaman and Myrobalan 29c rootstocks under drought stress, while GF677 and GN15 did not differ significantly from the control. The rootstocks responded to drought stress differently, so that leaf and root proline content, leaf and root soluble sugars and water-use efficiency (WUE) were higher for GF677 and GN15 compared with Cadaman or Myrobalan 29c.

In this study, with the aim of final evaluation to introduce the cultivar, the fruits of Khoram mandarin (Citrus reticulata ‘Clementine’ ×C. sinensis ‘Hamlin’) were used as a new cultivar and Clementine (Citrus clementina Hort. Ex Tanaka) as the control. Fruits were evaluated at harvest time and 20 and 40 days of cool storage for two years. Results showed that the size and weight of Khoram fruits was less than Clementine (control). Khoram was more spherical with easy to mid peeling. Weight loss of Khoram fruit during storage was lower than control. Color indices as L*, a*, b*, hue, and CCI of peel in both cultivars were not changed significantly during storage. TSS and TA levels in Khoram fruits were higher than control. The juice percentage of Khoram fruit was higher (48.45%) than Clementine (40.12%). Khoram fruits had the highest antioxidant capacity (34.29%) after 20 days of storage. Phenolic content of Khoram peel at harvest time and at the end of the storage was lower than control. The vitamin C content of both cultivars was not changed significantly during storage. Sensory traits such as taste, sweetness, peel and pulp appearance, and overall acceptance were dominant in Khoram fruits. In general, Khoram cultivar is suitable for freshness, moderate storability, good taste, high juice percentage and optimal nutritional value.

In order to evaluate the effects of different concentrations of gibberellic acid and vermicompost on some morphological and biochemical characteristics of daffodil (Narcissus tazetta L.) an experiment was conducted as factorial based on completely randomized design in greenhouse conditions. The first factor was vermicompost at 4 levels: 0 (control), 10%, 15% and 20% V/V. The second factor was gibberellic acid applied at 3 concentrations: 0 (control), 150 and 300 mg L-1 by soaking bulbs for 48 hours. The results showed that compared to the control, the effect of gibberellic acid and vermicompost decreased the time of flowering by 12.66 days, though increased flower pedicel and diameter by 26.3 and 0.83 mm, respectively and flower longevity by 8.66 day. Also, leaf fresh and dry weight increased by 7.33 and 0.31 g, respectively, leaf calcium 0.98%, flower relative fresh weight on days 3rd, 5th, and 7th by 6.39%, 7.59% and 19.17% respectively. Chlorophyll a, b and total also increased by 0.51, 0.94 and 1.46 mg g-1 FW respectively. In general, it can be stated that the simultaneous application of gibberellic acid and vermicompost was effective in improving all measured traits of Narcissus tazetta. Vermicompost 20% V/V and gibberellic acid 300 mg L-1 showed the best results.

In photosynthetic microorganisms, a series of electron carriers (such as flavodoxin) with the similar function to ferredoxin are expressed following the adverse reduction of ferredoxin under stress conditions. Fld gene reduces disorders of abiotic stresses in the electron transfer processes of photosynthesis. In order to investigate the morphological characteristics of transgenic walnuts harboring Fld ‎gene under salinity stress, a factorial experiment was conducted based on completely randomized design with four replications. In this experiment, transgenic Persian walnut plants expressing Fld (L2, L3, L13 and L17) and ‘Chandler’ as control under different levels ‎of NaCl ‎ (0, 100, and 200 mM) were evaluated under in vitro conditions. According to the results, L13 had the maximum number of healthy leaves (1.14), callus diameter (1.36mm) and number of regenerated leaves (1.13) using 200 mM NaCl. Transgenic lines maintained their natural growth in mild stress after 35 days under 200 mM NaCl, while non-transgenic plants showed injury symptoms in this treatment. In vitro studies showed that the transfer of Fld gene to Persian walnut ‘Chandler’, which is a salt-sensitive plant, improved its growth traits under salinity stress.

In this study, in order to evaluate the effects of drought stress on photosynthetic capacity of 17 different landraces and two commercial tomato hybrids, plant irrigation was stopped at the seedling stage and the changes in photosynthetic capacity during seven days of water withholding was measured by OJIP test. The results showed that the relative maximal variable fluorescence (FM/F0), electron transport flux per reaction center (ET0/RC), maximum quantum efficiency of PSII (FV/FM or FP0) and performance index on the absorption basis (PIabs) were decreased in drought-induced plants. In these plants, specific energy fluxes per reaction center for energy absorption (ABS/RC), trapped energy flux per reaction center (TR0/RC) and dissipated energy flux per reaction center (DI0/RC) were increased. The values of decrease and increase in plants were different, indicating the difference in drought tolerance levels in plants. The results also showed that the more drought-tolerant plants had less difference in the values of the parameters compared to their control. The results of this study help us to find the differences between the responses of the parameters related to the health of the plants photosynthetic capacity and provide theoretical foundations for improving tomato tolerance to dry climatic conditions.

In order to investigate combined effects of foliar application of plant growth regulators (naphthalene acetic acid and benzyl adenine at 50 mg L-1) and mammalian sex hormones (ethinyl estradiol and progesterone at 1.0 mg L-1) on strawberry cv. Camarosa, an experiment was carried out during the growing season, at the harvest time and also during 4 weeks of cold storage (4 °C) in 2018. The results showed that the foliar application of two hormones combined with benzyl adenine, naphthalene acetic acid, progesterone and ethinyl estradiol could be able to improve the growth traits, morphological, biochemical (total soluble solids, titratable acidity, chlorophylls and vitamin C) and antioxidant enzymes activity (peroxidase, catalase, superoxide dismutase and glutathione reductase) of strawberry fruits during the growing season as well as at the harvest time. During 4 weeks of cold storage, the biochemical traits and antioxidant enzymes activity of fruits were changed; in the meantime, the applied treatments significantly maintained fruit quality at the optimum level. Overall, the results revealed that the combined treatment of 1.0 mg L-1 ethinyl estradiol with 1.0 mg L-1 progesterone was the most effective treatment to maintain the quality of strawberry fruit cv. Camarosa during storage.

The 2- and 3-year-old of 60 apple combinations of 'Golden Delicious' and 'Red Delicious' onto promising clonal rootstocks tolerant to crown rot series along with 6 common clonal rootstocks were assessed for dwarfing potential. Branch length and number, internode length, active vegetative buds, annual shoots growth and diameter, sapling height, growth habit, root-sucker number and length per sapling, diametric values of rootstock, graft point and scion as well as pest/disease damages were assessed. The modified dwarfism ranking method was achieved in 5 groups, based the length of lateral branches per sapling. So, the rootstock series were ranked in very dwarfing (8 hybrids), dwarfing (6 hybrids), mid dwarfing (6 hybrids), vigorous (7 hybrids) and very vigorous (3 hybrids). The three categories of very-dwarfing, dwarfing and mid- dwarfing had the least shaded area compared to controls as the worldwide dwarfest ones. ANOVA and mean comparisons by Dunken test of the growth traits particularly lateral branches length and number, sapling height and annual branch length of the two scion cultivars was achieved related to M7 combinations. The trial was compiled within RCBD.