Effects of plant growth promoting rhizobacteria (PGPR) on yield,growth and nutrient contents in organically growing raspberry

During 2003 and 2005, plant growth promoting effects of two Bacillus strains OSU-142 (N₂-fixing) and M3 (N₂-fixing and phosphate solubilizing) were tested alone or in combinations on organically grown primocane fruiting raspberry (cv. Heritage) plants in terms of yield, growth, nutrient composition of leaves and variation of soil nutrient element composition in the province of Erzurum, Turkey. The results showed that Bacillus M3 treatment stimulated plant growth and resulted in significant yield increase. Inoculation of raspberry plant roots and rhizosphere with M3 and/or OSU-142 + M3, significantly increased yield (33.9% and 74.9%), cane length (13.6% and 15.0%), number of cluster per cane (25.4% and 28.7%) and number of berries per cane (25.1% and 36.0%) compared with the control, respectively. In addition, N, P and Ca contents of raspberry leaves with OSU-142 + M3 treatment, and Fe and Mn contents of the leaves of raspberry with M3 and OSU-142 + M3 applications significantly improved under organic growing conditions. Bacterial applications also significantly effected soil total N, available P, K, Ca, Mg, Fe, Mn, Zn contents and pH. Available P contents in soil was determined to be increased from 1.55 kg P₂O₅/da at the beginning of the study to 2.83 kg P₂O₅/da by OSU-142, to 5.36 kg P₂O₅/da by M3 and to 4.71 kg P₂O₅/da by OSU-142 + M3 treatments. The results of this study suggest that Bacillus M3 alone or in combination with Bacillus OSU-142 have the potential to increase the yield, growth and nutrition of raspberry plant under organic growing conditions.     

Effects of floral and foliar application of plant growth promoting rhizobacteria (PGPR) on yield, growth and nutrition of sweet cherry

During 2003 and 2005, plant growth promoting effects of Pseudomonas BA-8 and Bacillus OSU-142 were tested alone or combinations on sweet cherry (Prunus avium L.) cv. 0900 Ziraat in terms of yield, growth, nutrient composition of leaves in the province of Konya, Turkey. The presence of Pseudomonas BA-8, Bacillus OSU-142 and BA-8 + OSU-142 stimulated plant growth and resulted in significant yield increase. Floral and foliar applications of BA-8, OSU-142 and BA-8 + OSU-142 in sweet cherry significantly increased yield per trunk cross-sectional area (16.3, 10.9 and 21.7%), fruit weight (4.15, 5.37 and 1.24%) and shoot length (11.3, 11.8 and 29.6%), respectively, compared with the control. In addition, N, P and K contents of sweet cherry leaves with BA-8, OSU-142 and BA-8 + OSU-142 treatments, Fe and Zn contents of leaves with BA-8 + OSU-142 treatment and Mn content of the leaves of sweet cherry with BA-8 and OSU-142 applications significantly increased. Nitrogen, P and K contents in leaves were determined to be increased from 2.00, 0.17 and 0.43% in the control to 2.19, 0.20 and 0.54% by BA-8 application, to 2.32, 0.24 and 0.54% by OSU-142 application and to 2.43, 0.22 and 0.51% by BA-8 + OSU-142 application, respectively. Co-inoculation of BA-8 + OSU-142 increased Fe and Zn contents of leaves up to 50.5 and 35.5% compared with the control, respectively. Manganese content of leaves significantly also increased by BA-8 (26.6%) and OSU-142 (27.0%) applications compared with the control. The results of the present study suggested that Pseudomonas BA-8 and Bacillus OSU-142 alone or in combination have a great potential to increase the yield, growth and nutrition of sweet cherry plant.     

Effects of plant growth promoting bacteria (PGPB) on yield,growth and nutrient contents of organically grown strawberry

The effects of plant growth promoting bacteria (PGPB) on the fruit yield, growth and nutrient element content of strawberry cv. Fern were investigated under organic growing conditions between 2006 and 2008. The experimental plot was a completely randomized design with 3 replicates. Three PGPB strains (Pseudomonas BA-8, Bacillus OSU-142 and Bacillus M-3) were used alone or in combination as bio-fertilizer agent in the experiment. Data through 3 years showed that the use of PGPB significantly increased fruit yield, plant growth and leaf P and Zn contents. Root inoculation of M3 and floral and foliar spraying of OSU-142 and BA-8 bacteria stimulated plant growth resulting in significant yield increases. M3 + BA-8, BA-8 + OSU-142, M3, M3 + OSU-142 and BA-8 applications increased cumulative yield by 33.2%, 18.4%, 18.2%, 15.3% and 10.5%, respectively. Number of fruits per plant significantly increased by the applications of M3 + BA-8 (91.73) and M3 (81.58) compared with the control (68.66). In addition, P and Zn contents of strawberry leaves with bacterial inoculation significantly increased under organic growing conditions. Available P contents in soil were increased from 0.35 kg P₂O₅/da at the beginning of the study to 2.00, 1.97 and 1.82 kg P₂O₅/da by M3 + OSU-142, M3 + BA-8 and M3 + BA-8 + OSU-142 applications, respectively. Overall, the results of this study suggest that root inoculation of Bacillus M3 alone or in combination with spraying Bacillus OSU-142 or Pseudomonas BA-8 have the potential to increase the yield, growth and nutrition content of strawberry plant under organic growing conditions.     

Alteration of tomato fruit quality by root inoculation with plant growth-promoting rhizobacteria (PGPR): Bacillus subtilis BEB-13bs

In this study the effect of inoculation of tomato (Lycopersicon esculentum Mill.) roots with plant growth-promoting rhizobacteria (PGPR) on yield and fruit quality was evaluated. The control treatment was non-inoculated (CTL) and the PGPR treatment was inoculated with Bacillus subtilis BEB-lSbs (BS13). Yield per plant and marketable yield, as well as fruit weight and length were increased by the BS13 treatment when compared to the CTL treatment. Texture of red fruits was also enhanced by the BS13 treatment compared to that in the CTL treatment. These results demonstrated that PGPR have positive effects on tomato fruit quality attributes, particularly on size and texture.     

Girdling and summer pruning in apple increase soil respiration

The root system of plants derives all its energy from photosynthate translocated from the canopy to the root system. Canopy manipulations that alter either the rate of canopy photosynthesis or the translocation of photosynthate are expected to alter dry matter partitioning to the root system. Field studies were conducted to evaluate the effect of trunk girdling (2008 and 2009) and summer pruning (2009) on soil respiration, maximum quantum yield efficiency of photosystem II and leaf carbohydrate content. In apple trees, following trunk girdling there was increased soil respiration in association with a significant rainfall event suggesting rapid release of organic matter and subsequent microbial decomposition of the carbon. Soil respiration rates returned to baseline levels over time. Reduction in midday maximum quantum efficiency of photosystem II (RPSII) was increased by girdling when crop load was low and this reduction was not related to leaf carbohydrate levels. Girdling reduced leaf sucrose and sorbitol levels in both years, however, total leaf carbohydrates were not affected by girdling. Summer pruning increased soil respiration within 2 weeks of treatment in association with a significant rainfall event, also suggesting a release of organic matter and microbial decomposition of the carbon. Cultural practices that severely affect canopy sink source relationships such as girdling and summer pruning increase soil respiration, however these effects appear to be very short lived, 3–10 days, followed by recovery of the soil/root system to similar levels of soil carbon dioxide efflux. These cultural practices do not likely pose a long-term detrimental effect on root system efficiency because the effects are of short duration with apparent recovery.     

Rootstock effect on growth of apple scions with different growth habits

Apple scions with diverse growth habits were grafted on various size-controlling rootstocks and morphological characteristics were measured after 6 years of growth in the field. Scion had more influence than rootstock on monthly growth rate. Across all rootstocks, scions with spreading growth habits grew rapidly in April and May and achieved most seasonal growth earlier than scions with upright growth habits that grew slowly early in the season. In all growth habits and rootstocks, growth rate slowed appreciably but did not cease by August and growth did not terminate earlier for any one scion–rootstock combination. Across all scions, the dwarfing rootstock, M.9, consistently had the lowest and seedling rootstock had the greatest tree height and trunk diameter. However, no one size-controlling rootstock consistently influenced dates of bud break and full bloom, shoot elongation rate, or duration of growth. Tree growth form was not fundamentally affected by rootstock. Significant interactions indicated that effects of size-controlling rootstock on components of shoot growth will vary with apple tree growth habit. These effects on phenology and development can be significant to growers and may assist breeders in developing new apple cultivars.     

Effects of the commercial product based on Trichoderma harzianum on plant,bulb and yield characteristics of onion

Effects of the commercial product TrichoFlow WP™ (Agrimm Technologies Ltd., New Zealand), based on the fungus Trichoderma harzianum, on quality characteristics and yield of bulb onion was investigated. Bulb sets of the local cultivar Kantartopu was planted in soil with in and between row distances of 0.15 m and 0.40 m, respectively. The product, at considerably high dosages of 5 g m⁻², 10 g m⁻² and 15 g m⁻², was mixed with water and sprinkled once to the plots at planting. Analyses of data at harvest did not show statistical significance for Trichoderma effect on total bulb yield, bulb diameter, leaf length, number of shoot apex, %titratable acidity, number of internal (fleshy) leaves, number of external (papery) leaves, %soluble solids and %bulbs with diameters of 20–39 mm, 40–69 mm and ≥70 mm. The yields obtained from the plots treated with the dosages of 5 g m⁻², 10 g m⁻² and 15 g m⁻² and the control plots were 1063.7 kg da⁻¹, 1051.0 kg da⁻¹, 1066.5 kg da⁻¹ and 985.0 kg da⁻¹, respectively. Our results showed that high dosages of the Trichoderma product were not effective in enhancing onion bulb and yield characteristics under the given conditions.     

Effect of plant growth promoting rhizobacteria on young apple tree growth and fruit yield under orchard conditions

The effects of rootstocks (M9 and MM 106), cultivars (Granny Smith and Stark Spur Golden) and growth promoting rhizobacteria (OSU-142, OSU-7, BA-8 and M-3) on the tree growth and yield at apple (Malus domestica Borkh) trees were studied in a clay loam soil in the eastern Anatolia region of Turkey in 2002–2004. Plant growth promoting rhizobacteria (PGPR) were capable of producing indole acetic acid (IAA) and cytokinin, but three of them (OSU-7, BA-8 and M-3) were also able to dissolve phosphate. Maximum shoot number of apple trees was found after inoculation with BA-8 followed by OSU-7 and M-3. All the inoculated PGPR strains contributed to the increase in fruit yield of apple when compared to control but it was strongly depended on rootstocks, cultivars and treatments. Plant growth responses were variable and dependent on bacterial strains, rootstock and cultivar and growth parameters evaluated of young apple trees. Newly planted apple trees inoculated with OSU-142, OSU-7, BA-8 and M-3 PGPR increased average shoot length by 59.2, 18.3, 7.0 and 14.3% relative to the control and fruit yield by 116.4, 88.2, 137.5 and 73.7%, respectively. Bacterial inoculation increased shoot diameter from 7.0 to 16.3% when compared to control. The production of plant growth hormones has been suggested as one of the mechanisms by which PGPRs stimulate young apple sapling growth. The growth-promoting effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. In view of environmental pollution due to excessive use of fertilizers and high costs of the production of fertilizers, PGPR strains tested in our study have potential to be used for the sustainable and environmentally benign horticultural production.     

Effects of different mulches and irrigation methods on root growth,nutrient uptake,water-use efficiency and yield of strawberry

Field studies were conducted for two consecutive years under sub-temperate climatic conditions at Nauni in district Solan of Himachal Pradesh (30°52′N, 77°11′E 1175 asl) on loamy sand Inceptisols to investigate the effect of different mulches (hay: HM, black polyethylene: BP) on root growth, nutrient uptake, water-use efficiency (WUE) and yield of strawberry cv. Chandler under drip (DI) and surface irrigation (SI) systems. Unmulch (UM) and rainfed treatments were kept as control. Higher soil moisture content was registered under both the mulch materials during entire crop growth period. However, it was greater under BP mulch as compare to HM. The moisture conservation increased by 2.80–12.80% under BP mulch as compared to UM. HM treatment, irrespective of irrigation method increased the minimum soil temperature (2.8–5.2 °C) and reduced the maximum soil temperature (2.7–5.8 °C) as compared to UM. BP mulch increased the minimum soil temperature from 0.4 to 2.5 °C. Application of irrigation moderated the soil (minimum 2.6 and maximum 1.4 °C) temperature. Both the mulch materials were effective in enhancing root growth, nutrient uptake, WUE and yield. Application of mulch enhanced the root growth (63%), nutrient uptake (179.20%), WUE (84.40%) and yield (343%) under DI. However, respective increase under SI was 23.60, 83.80, 109.40 and 219.20%. Under DI, 51% of irrigation water was saved and about 19% higher fruit yield was obtained as compared with SI treatment. Linear regression model could significantly describe the variations in nutrient uptake (N, P and K) and WUE of strawberry under sub-temperate climatic conditions, root mass density was better indicator for estimating nutrient uptake of strawberry.     

Parameters of inner quality of the apple scab resistant and susceptible apple cultivars (Malus domestica Borkh.)

Individual organic acids and sugars were analysed in the fruits of scab resistant and susceptible apple cultivars. The total sugars ranged between 128.2 and 191.6 g/kg, and the total organic acid between 5.1 and 13.4 g/kg. In the flesh and peels of different apple varieties single phenolics (gallic, protocatehuic, chlorogenic, caffeic, ferulic and p-coumaric acid, phloridzin, epicatechin, catechin, quercitrin and rutin) were analysed together with their total phenolic content (TPC). ‘Golden Delicious’ was the cultivar with the lowest TPC whereas ‘Rubinola’, ‘Jonagold’ and ‘Goldrush’ had the highest level of TPC in the pulp. Peels showed a 2–9 times higher phenolic content than the pulp. ‘Goldrush’ had the highest content of TPC in its peel. The total antioxidant capacity of peels was about 2–5 times higher than respective pulps. Scab resistant apple cultivars had significantly higher content of some single and total phenolic contents in comparison with the scab susceptible, especially the pulp.     

Biofertilizers improve plant growth,fruit yield,nutrition, metabolism and rhizosphere enzyme activities of Pomegranate (Punica granatum L.) in Indian Thar Desert

Production of horticultural crops has undergone enormous change in recent years due to development of innovative technologies including integrated nutrient management practices using biofertilizers. The present study represents the positive response of biofertilizers in nursery seedlings followed by their transplantation in harsh field conditions of Indian Thar Desert. Nursery and field experiments were carried out to assess the effectiveness of selected N₂-fixing bacteria and AM fungi alone or in combination, on the growth and biomass production of Punica granatum. In both experiments, the combined treatment of Azotobacter chroococcum and Glomus mosseae was found to be the most effective. Besides enhancing the rhizosphere microbial activity and concentration of various metabolites and nutrients, these bioinoculants helped in better establishment of pomegranate plants under field conditions. A significant improvement in the plant height, plant canopy, pruned material and fruit yield was evident in 5-year-old pomegranate plants in field conditions. In view of the above results, use of biofertilizer technology may be adopted for the establishment and development of other horticultural plant species in arid regions.     

Genetic assessment of local apple cultivars from La Palma,Spain, using simple sequence repeats (SSRs)

Apple cultivars from Canary Islands can possibly be valuable genetic resources for subtropical areas. We localised 31 accessions considered by growers to be local, and confirmed by historical references that apple crop was introduced in XV century. These accessions were compared with 77 Spanish and 26 commercial cultivars in order to detect synonyms. A set of 10 SSRs were studied, and 2 of them presented 2 loci. Cultivars from La Palma (Canary Islands) presented five specific alleles not found in other Spanish regions. Those polymorphisms allowed detecting one introgressant in La Palma from non-native cultivars, and the other 30 accessions were classified into 14 genotypes. Some accessions derived from non-native cultivars such as Golden Delicious. A main cultivar could be detected, Del País, with 14 accessions. Secondary ones were Camuesa and Pero. Genetic differentiation was small between regions (Fst = 0.057) but significant, confirmed by analysis of molecular variance (AMOVA). Major genetic differentiation was found between non-native cultivars and cultivars from Asturias and Basque Country. Bayesian method and admixture analysis reconstructed three ancestral groups (RPP), Asturian and Basque cultivars grouped in RPPI (mainly those used for cider production), a mixture of cultivars from Galicia and La Palma in RPPII and non-native cultivars were in RPPIII. This genetic differentiation was also confirmed by factorial correspondence analyses (FCA). AMOVA over RPPs increased the genetic differentiation. Allelic variation found in this study showed that Spanish local cultivars represent a differentiated genetic pool that will provide original genotypes to diversify the reduced number of cultivars used in commercial production. In addition, differentiated genotypes localised in La Palma will be preserved in the local Germplasm Bank.     

Effects of plastic mulches on root zone temperature and on the manifestation of tomato spotted wilt symptoms and yield of tomato

Tomato spotted wilt (TSW) disease is a serious constraint to tomato production in various regions of the world. The effect of TSW on tomato yield is largely influenced by time of infection. Early infection usually results in severe stunting of the seedling and even death of the plant. Plastic film mulches affect both the incidence of TSW, and plant growth and yield of tomato. The objective of the present study was to determine the effect of root zone temperature (RZT) as affected by plastic film mulch on the manifestation of symptoms of TSW, and growth and yield of tomato plants either artificially inoculated with tomato spotted wilt virus (TSWV) or under natural TSW infection. In artificially inoculated plants as well as in plants under natural TSW infection, vegetative top fresh weight (FW) and fruit FW both increased with the length of time after transplanting that the plants remained free from TSW symptoms. The root zone temperature was highest under black mulch (seasonal mean = 27.5 °C), followed by gray (27.0 °C), silver (25.8 °C), and white (24.8 °C) mulches. The plants grown on black mulch showed the earliest appearance of TSW symptoms, and had significantly reduced vegetative growth and fruit yields compared to plants on the other mulches. In conclusion, utilization of plastic mulches that created conditions of high RZT stress resulted in reduced plant growth and yield and predisposed the plants to earlier expression of TSW symptoms compared to plants grown at RZTs more favorable to tomato plant growth (optimal RZT = 26.1 °C [Díaz-Pérez, J.C., Batal, K.D., Granberry, D., Bertrand, D., Giddings, D., Pappu, H., 2003. Vegetative top growth and yield of tomato grown on plastic film mulches as affected by the appearance of symptoms of Tomato spotted wilt virus. HortScience 38, 395–399]). Since these plant responses to TSW under heat stress occurred in artificially inoculated plants as well as in plants under natural TSW infection, high RZTs probably affected the plants directly, independently of any possible effects on the thrips vectors.     

Heat treatment and harvest date interact in their effect on superficial scald of ‘Granny Smith’ apple

A study was made of the effect of hot water dips (HWD) at temperatures of 42, 44, 46 and 48 °C (HWD 42 °C, HWD 44 °C, HWD 46 °C and HWD 48 °C, respectively) for 3 min on development of superficial scald and the concentration of α-farnesene and conjugated trienols (CT), CT₂₅₉, CT₂₆₉, CT₂₈₁, as well as OD₂₀₀ on Granny Smith apple fruits harvested on three dates and stored 125 days in air at 2 °C. HWD 48 °C efficiently decreased surface scald in the second and third harvest. α-Farnesene and CT were measured spectrophotometrically and by HPLC. No clear relationship of OD₂₀₀ and scald development was observed. Correlation of scald index and OD₂₀₀ at the end of storage was negative for the second harvest date. There was no significant correlation between the scald index and CT₂₅₉. Scald index was positively correlated with CT₂₆₉ after 80 days for the second and third harvest and at the end of storage for the second harvest. CT₂₈₁ was spectrophotometrically detectable only at the end of the storage, for the third harvest date, in control, HWD 42 °C, and HWD 44 °C. HWD 42 °C had significantly higher CT₂₈₁ compared to HWD 44 °C and control. HPLC analysis of control samples revealed presence of CT₂₈₁ in all three harvest dates, and presence of at least two components, as was the case of CT₂₅₉ and CT₂₆₉. The ratio of these two components was different for all three CT species. Fruit maturity was an important factor determining the response of fruit to heat and occurrence of superficial scald. The results indicate that a successful treatment using HWD to control superficial scald may be obtained after further research and that there are still some questions on the role of different CT's in scald biochemistry that should be addressed in future research.     

Effect of three Greek arbuscular mycorrhizal fungi in improving the growth,nutrient concentration,and production of essential oils of oregano and mint plants

Arbuscular mycorrhizal fungi have been widely used in agriculture to improve the cultivation of many crops. One of the aims of this study was the isolation and molecular identification of arbuscular mycorrhizal fungi isolated from mountain areas of Northern Greece (Ritini Pieria, Elatochori Pieria, Ambelakia Ossa). Only three isolates were obtained; two of Glomus etunicatum and one of G. lamellosum. The second objective of this study was to investigate the effect of these arbuscular mycorrhizal fungi on the concentration of macro- and micronutrients in tissues, the quantity and quality of essential oils and the growth of oregano and mint plants (two widely used aromatic plants in Greece). It was found that mycorrhizal oregano and mint plants had a higher content of essential oils and nutrient elements, and grew better than non-mycorrhizal plants. In addition, the composition of the essential oil in mycorrhizal plants differed from the oil of non-mycorrhizal plants. These results suggest that the use of mycorrhizal fungi may allow plant growth in low fertility soils, reduce fertilizer inputs and increase aromatic plant production of essential oils, They also indicate that it may be possible to use mycorrhizae to affect the quality of the essential oil produced.     

Harvest and post-harvest apple fruit quality following applications of kaolin particle film in South African orchards

Sunburn on apples in the Western Cape region of South Africa can result in yield losses of up to 50%. Application of kaolin-based particle film (Surround^® WP) increases leaf and fruit surface reflectivity, thus potentially reducing heat load and sunburn. Trials were performed during 2002/2003 and 2003/2004 to assess the effectiveness of kaolin particle film in controlling sunburn on ‘Granny Smith’, ‘Braeburn’, ‘Fuji’, ‘Royal Gala’ and ‘Cripps’ Pink’ apples. Fruit quality and ripening were monitored following 1–4 months in regular atmosphere cold storage at −0.5 °C. Sunburn on exposed fruit was significantly reduced in ‘Granny Smith’ and ‘Fuji’. Kaolin treatment improved fruit colour of ‘Granny Smith’ and ‘Royal Gala’, and delayed starch conversion in ‘Granny Smith’ at harvest and during the early storage period but not thereafter. Incidence of watercore at harvest was significantly reduced by kaolin treatment, but this disorder disappeared during cold storage in both treatments. There were no effects on skin anthocyanin or phenolic concentrations in any cultivar compared to unsprayed fruit.     

Integration of soil solarization and chemical sterilization with beneficial microorganisms for the control of white root rot and growth of nursery apple

White root rot (Dematophora necatrix (Mart.)) is a serious disease of apple (Malus domestica Borkh) in nurseries and orchards in India. In 2002 and 2003, field experiments were conducted to integrate soil solarization with native isolates of Azotobacter chrococcum and vesicular–arbuscular mycorrhizal fungi and observe its effect on the incidence of white root rot and growth of the saplings. Apple seeds coated with two native isolates of A. chrococcum (AZUHF₁ and AZUHF₂) were sown in plots inoculated with 4 native isolates of va-mycorrhiza, i.e. AMUHF₁ (Glomus fesiculatum), AMUHF₂ (Glomus macrocarpum), AMUHF₃ (Glomus mosseae) and AMUHF₄ (Gigaspora sp.) in 14 different combinations and these plots were solarized with transparent polyethylene mulch (25 μm thick) for 40 days in summer months. Soil solarization resulted around 9 °C higher temperature with average maximum temperature of 38–39 °C. Inoculation of saplings with AMUHF₁ isolate of va-mycorrhiza and AZUHF₁ isolate of A. chrococcum and then their planting in solarized soil was found most effective with no incidence of white root rot in comparison to 33.6–35.4% in control accompanied with 78–113% increase in shoot length and 81.6–84.3% increase in root length. Shoot and root length of the saplings was 9.6–10.6 and 9.2–16.0% higher, respectively, in solarized plots in comparison to sterilized plots.     

Vegetative and productive responses of ‘Conference’ and ‘Williams’ pear trees planted at different in-row spacings

The effect of in-row spacing on the vegetative and productive performance of 4-year-old ‘Conference’ (CON) and ‘Williams’ (WIL) pear trees was studied. Analysis of digital images was used to estimate canopy growth and conformation. Fruit quality was determined by measuring fruit weight, flesh firmness, peel color, soluble solid content, and titratable acidity. WIL produced more and more efficiently than CON, especially at closer spacings. WIL canopies were generally bigger than CON canopies, and reduced spacing penalized stem growth and influenced canopy conformation. Root growth and conformation was similar for both cultivars, whereas decreasing in-row spacing reduced root dry weight, length, volume, and spread area only in WIL. Also, WIL trees partitioned more to fruit and leaves compared to CON, and increasing spacing resulted in a relative shift toward vegetative growth. CON fruit was smaller but sweeter and less acidic than WIL fruit. Increasing spacing influenced negatively WIL fruit quality parameters, with the only exception of fruit weight, which was increased. For the range of in-row spacing considered, our results indicate that WIL may represent a more efficient and competitive option than CON for high-density plantings, at least in the early stages of orchard life.     

The impact of sodium chloride on root growth,cell division,and interphase silver-stained nucleolar organizer regions (AgNORs) in root tip cells of Allium cepa L.

To evaluate genetic damage, parameters including root growth, chromosomal aberrations, and interphase silver-stained nucleolar organizer regions (AgNORs) in root tip cells of Allium cepa L. were investigated after treatment with NaCl (40–160 mM). The results showed that NaCl caused a decrease in root growth. All concentrations of NaCl showed an inhibitory effect on dividing cells in root tips of A. cepa L. and caused a reduction in mitotic index values. Upon exposure to NaCl, roots exhibited various mitotic abnormalities, including c-mitosis, anaphase bridge, and chromosome stickiness. In addition, interphase cells with micronuclei, budding nuclei, and unequal-sized nuclei were observed. Moreover, total cell aberration increased with increasing NaCl concentration. For AgNOR parameters, the average number of AgNORs per nucleus decreased in roots treated at all NaCl concentrations. The singular AgNOR area and whole AgNOR area in the nucleus containing 1–3 AgNORs were inversely proportional to NaCl concentrations.