Effect of fruit-load on the growth,absorption, and partitioning of inorganic nutrients in young ‘Fuyu’ persimmon trees

Tree growth and the increase in inorganic nutrients during a growing season were studied in 3-year-old, container-grown ‘Fuyu’ persimmon trees with different levels of fruit-load. Fruit-load was varied by adjusting the leaf–fruit ratio to 10, 20, 30, and 60 on July 5. Some trees were completely defruited. The whole trees were harvested on November 5 of that year, and increases in dry weight and inorganic elements in different tree parts during the season were measured. A lower leaf–fruit ratio resulted in a higher yield but also decreased fruit weight, soluble solids, and fruit color. Dry weight of the aerial woods and root increased significantly with a greater ratio. However, total dry weight including the fruits was higher in the lower ratio trees than in the higher ratio trees; the weight of a tree that maintained the ratio of 10 was 35% higher than a tree without fruit. Fruits accounted for 62% of total dry weight when the ratio was 10 and 27% when the ratio was 60. The leaf–fruit ratio did not significantly alter the total increase in P, K, Ca, and Mg content. N tended to decrease with an increasing leaf–fruit ratio. Of the total increases of N, P, and K during the season, the fruits accounted for 30%, 50%, and 54% at the ratio of 20, respectively, and the percentages increased to 44, 81, and 74 at the ratio of 10. The inorganic element content in the aerial woods and root tended to increase with greater ratios, especially in the root. When trees were defruited, N and K increases in the root accounted for 44% and 35% of the total increase, respectively. These results indicated that persimmon orchard fertilization programs with different fruit-load levels should accommodate the proportion of nutrients partitioned to fruits that are removed permanently from the tree.     

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.     

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.     

Response of evergreen perennial tree crops to gibberellic acid is crop load-dependent: II. GA3 increases yield and fruit size of ‘Hass’ avocado only in the on-crop year of an alternate bearing orchard

Despite problems of low fruit set, small fruit size and alternate bearing, the Hass cultivar dominates commercial avocado production worldwide. To increase yield and fruit size, gibberellic acid (GA₃) (25 mg L⁻¹) was applied at different stages of ‘Hass’ avocado tree phenology: (i) mid–late April (flower abscission), end of June–beginning of July (fruit abscission and beginning of the exponential phase of fruit growth), and mid-January (beginning of pre-harvest fruit drop); (ii) end of June–beginning of July; and (iii) mid-September (near the end of the major fruit abscission period; period of exponential fruit growth). In both years of the research, applications of GA₃ in April and June–July were within the periods of intense flower and fruit abscission, respectively; fruit abscission was low in September and January. Maximum air temperature was not related to flower or fruit abscission. In the on-crop year (391 fruit per untreated control tree), a single application of GA₃ at the end of June–beginning of July significantly increased total yield (kilograms only) and yield of commercially valuable fruit (178–325 g/fruit) (as kilograms and number per tree) compared with the control (P < 0.0001). GA₃ applied in September increased total yield (kilograms only) and yield of commercially valuable fruit (kilograms and number per tree) to values intermediate to and not significantly different from all other treatments, except trees receiving multiple applications of GA₃. This treatment reduced total yield and yield of commercially valuable fruit (kilograms and number per tree) relative to all treatments (P ≤ 0.0002). In contrast, during the off-crop year (32 fruit per control tree), no GA₃ treatment had a significant effect on yield or fruit size compared with the control and all other GA₃ treatments. For ‘Hass’ avocado, there was no negative effect from applying GA₃ at the end of June–beginning of July in both the off- and on-crop years; 2-year cumulative total yield and yield of commercially valuable fruit were increased by 27 kg (128 fruit) and 22 kg (101 fruit) per tree, respectively, above the yield of untreated control trees (P < 0.0001).     

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.     

Relationships between yield components in first cropping year and average yield of short-day strawberries over two main seasons

Fruit productivity of the garden strawberry, Fragaria × ananassa Duch., is a result of interrelationship of yield components contributing to it directly or indirectly. The main aim of the investigation was to find out whether there exists any general regularity, connecting relationships between main yield components in first cropping year to average yield of two main seasons. Two successive studies which primarily included 23 genotypes, differing in yield components and productivity, each, were planted in field conditions in spring 1999 and in spring 2000, respectively, and used for data collection to explore the material obtained in them. Four key yield components and average yields were measured in both cropping years, after which all possible ratios between the components were calculated to find out: first, the relationships to be influential on average yield of the two main seasons; second, type of the probable yield dependence upon the ratios; and, third, their values leading to high yields. Two ratios between the key yield components in first season, i.e.: inflorescence number per plant to branch crown number per plant, named ratio 1, and fruit weight (g) to flower count per inflorescence, named ratio 2, have been found to be related to average yield. An irregular surface, with a single peak falling approximately in its centre, describes average yield dependence upon the ratios. Values of the two ratios falling in the range of 1.0–1.6 each, provided that they are close, have enabled plants to produce high yields cumulatively over two first years. The paper highlights the most important differences in plant behaviour and yield dynamics of strawberry genotypes, depending on combinations of the ratios in first year, discerning those, which have been particularly advantageous to obtain very high yields, and are influenced by negative environmental factors least of all. Based on the findings, a method of predicting of average yield has been developed. Following this, usefulness of the method and possibilities of its using in strawberry breeding and variety trial are discussed.     

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.     

Effects of defoliation on fruit growth,carbohydrate reserves and subsequent flowering of ‘Hayward’ kiwifruit vines

A partial defoliation study was carried out on ‘Hayward’ kiwifruit vines with the aim of evaluating effects on fruit yield, changes in concentration of carbohydrates, and return bloom. At full bloom, ‘Hayward’ kiwifruit vines trained to the pergola system were submitted to 0% (control), 50% and 75% defoliation in the 2.0 m wide central horizontal area of the canopy. This area represents the vine ‘replacement cane zone’ (RCZ), whereas the remaining external area represents the ‘fruiting zone’ (FZ). Removing 50% of the leaves resulted in a small (−9 g in the RCZ and −3.3 g in the FZ), but significant, reduction in fruit weight compared to the control vines. More severe defoliation (75%) reduced fruit weight by 13 g in the RCZ and 7 g in the FZ. The defoliation treatment reduced the concentrations of starch and total soluble carbohydrates (glucose + fructose + sucrose) in the shoots and starch in trunk bark compared to those in control vines. The treatments caused a large reduction in return bloom, expressed as number of flowers per winter bud, by about 25% and 53% in vines with 50% and 75% defoliation, respectively.     

Pollination with laser-irradiated pollens breaks cross-incompatibility between zicaitai (Brassica campestris var. purpurea) and ornamental kale (Brassica oleracea var. acephala) to produce hybrids with the aid of ovule culture

The objective of this study was to produce interspecific hybrids between an Ogura-cytoplasmic male sterile (CMS) line of zicaitai (Brassica campestris var. purupurea, 2n = 20) and cultivars of ornamental kale (Brassica oleracea var. acephala, 2n = 18) to develop a CMS system for hybrid seed production. Pollination with pollen grains of ornamental kales irradiated at a power output of 9.0 mW with a He–Ne laser for 3 min could overcome the cross-incompatibility between the species concerned. Intact hybrids could be efficiently produced from ovules cultured on Murashige and Skoog media supplemented by 0.2 mg l⁻¹ 6-benzyladenine. Chromosome number of hybrids was confirmed to be 2n = 19. Hybrids resembled ornamental kales in leaf morphology and in vernalization response. Pollens of hybrids had a sterile appearance. Moreover the hybridity of the putative hybrids was confirmed by RAPD data on a DNA fragment of 820 bp.     

Comparison of anthocyanins in non-blotches and blotches of the petals of Xibei tree peony

A comparison in non-blotches and blotches of 35 cultivars of Xibei tree peony was investigated to explore flower coloration of Xibei tree peony (the second cultivar group in Chinese tree peony). With high performance liquid chromatography (HPLC) analysis, six anthocyanins including peonidin 3,5-di-O-glucoside (Pn3G5G), peonidin 3-O-glucoside (Pn3G), cyanidin 3,5-di-O-glucoside (Cy3G5G), cyanidin 3-O-glucoside (Cy3G), pelargonidin 3,5-di-O-glucoside (Pg3G5G), and pelargonidin 3-O-glucoside (Pg3G) were detected in non-blotches and blotches of petals. Total anthocyanins (TA), total flavones and flavonols (TF), and the copigmentation index (CI) were also analyzed. Cyanidin-based glycosides, which accumulated abundantly at the basal petal, resulted in blotch formation. Some peculiar cultivars with only one kind of anthocyanins or without anthocyanins in non-blotches were found in this study. For example, ‘Feng Zi Xiu Se’, ‘Ou Duan Si Lian’, and ‘Xi Wang’ contained only Pn3G5G; ‘Bing Shan Cang Yu’ and ‘Jin Bo Dang Yang’ contained only Cy3G; while no anthocyanins were found in ‘Bing Shan Xue Lian’. Several cultivars were rich in Pg-based glycosides, such as ‘Ni Hong Huan Cai’, and ‘Ju Yuan Shao Nv’. These cultivars would be excellent parents for creating new cultivars with novel flower color in the future.     

Differential structure and physiological response to canker challenge between ‘Meiwa’ kumquat and ‘Newhall’ navel orange with contrasting resistance

Asiatic citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most detrimental diseases affecting citrus production. ‘Meiwa’ kumquat (Fortunella crassifolia) and ‘Newhall’ navel orange (Citrus sinensis) are two genotypes with contrasting Xcc resistance. In the current study, efforts were made to perform pairwise comparison between them in terms of structural difference and biochemical response to Xcc attack. Pinprick inoculation demonstrated that ‘Meiwa’ had lower disease incidence rate and smaller lesion size, concurrent with significantly less bacterial number at the inoculation sites relative to ‘Newhall’. Microscopic observation demonstrated that stomatal density and size of ‘Meiwa’ were significantly smaller than ‘Newhall’. Stomatal apertures of ‘Meiwa’ were smaller than ‘Newhall’ measured at 2 h after their leaves were immersed in Xcc suspension, consistent with the bacteria number in the internal tissues counted at 4 d. Epicuticular wax content of ‘Meiwa’ was significantly higher than that of ‘Newhall’, while no difference in palisade and spongy tissue was observed between them. Enzymatic activity assay showed that after Xcc inoculation, ‘Meiwa’ exhibited significantly higher activities of catalase (CAT), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) in comparison with ‘Newhall’ at most of the sampling time points. Our data showed that the two genotypes with contrasting Xcc resistance exhibited clear difference in the structure and physiological response, which may provide information to facilitate our understanding of Xcc resistance.     

Dry weight and carbohydrate distribution in different tree parts as affected by various fruit-loads of young persimmon and their effect on new growth in the next season

This study was conducted to determine the changes in the accumulation of dry weight (DW) and the distribution of carbohydrates in different parts of young persimmon (Diospyros kaki) as affected by various fruit-loads. The effects of such changes were monitored with regard to the abundance of new growth in the following year. On June 15, the fruit-load was adjusted to a leaf–fruit (L/F) ratio of 10, 20, and 30, and some trees were completely defruited. Between June 15 and November 11, the increase in DW was less in the defruited and more in the higher L/F-ratio trees. Among the various tree parts, the DW increased the most in the fruits during the same period. It was observed that the lower the L/F ratio, the more the DW in the fruits: the fruits accounted for 78.7% of the total DW in the 10-L/F, 57.6% in the 20-L/F, and 49.7% in the 30-L/F ratio trees. In contrast, as the L/F ratio increased, the DW distribution to the roots increased to 3% in the 10-L/F, 13% in the 20-L/F, and 26% in the 30-L/F ratio trees and 61% in the defruited trees. During this period, carbohydrates were distributed mostly to the fruits, but as the L/F ratio decreased, their distribution to permanent tree parts decreased. The distribution of soluble sugars and starch to the permanent parts was 1% and 14% in the 10-L/F, 3% and 48% in the 20-L/F, 9% and 57% in the 30-L/F ratio trees, and 71% and 93% in the defruited trees, respectively. Maintaining a lower L/F ratio resulted in a decrease in the shoot and fruit numbers in the following year: there were zero and four fruits in those trees with an L/F ratio of 10 and 20, respectively. The carbohydrates decreased in the roots of both the 30-L/F ratio trees and the defruited trees, whereas the defruited trees showed more new shoot growth in the following year. In the roots of the trees with the L/F ratio of 30, soluble sugars and starch decreased by 7.6 g and 1.8 g, respectively, during the spring growth, whereas, in the roots of the defruited trees soluble sugars and starch decreased by 33.3 g and 94.6 g, respectively.     

Phytophthora nicotianae transmission and growth of potted kalanchoe in two recirculating subirrigation systems

Recirculating subirrigation systems are frequently exposed to the risk of plant pathogens transmission, which may deteriorate the growth and quality of the plants. The transmission of Phytophthora nicotianae was examined using Kalanchoe blossfeldiana cv. New Alter in two recirculating subirrigation systems, a nutrient-flow wick culture (NFW) system and an ebb and flow (EBB) system. When the nutrient solution was infested, the pathogen was recovered from roots in both subirrigation systems. However, foliar blights and browning of roots appeared 4 and 7 weeks, respectively, after inoculation in the EBB system. Only a little discoloration appeared in the NFW system. The fresh and dry weights were lower in the EBB system than in the NFW system. When growing medium was inoculated, the pathogen was unable to be isolated from the plants in the NFW system. However, disease symptoms appeared in the EBB system 4 weeks after inoculation, and the pathogen was observed in the basal leaves and roots. Similar to the infested nutrient solution, the plant growth in the EBB system was inhibited. These results suggested that when the nutrient solution was infested, pathogen transmission could occur in plants in both systems, although differences existed with regard to disease symptoms and the time it took for symptoms to appear. However, we observed that when growing medium was inoculated the pathogen was not transmitted to adjacent plants in the NFW system using wick.     

Application of genomic in situ hybridization for phylogenetic study between Mangifera indica L. and eight wild species of Mangifera

The phylogenetic relationship between mango (Mangifera indica L.) and eight wild species of Mangifera were analyzed by comparing signal intensity of genomic in situ hybridization (GISH) on somatic metaphase chromosomes of M. indica, using labeled DNA of eight wild Mangifera species. The eight wild species were divided into four groups based on intensity and number of hybridization signals on chromosomes of M. indica in GISH analyses. The probe of Mangifera sylvatica Roxb. gave the highest intensities on the chromosome of M. indica, indicating a close relationship between M. indica and M. sylvatica. For the other species, classification of GISH was comparable to that of the phylogenetic analysis using AFLP markers, as previously reported ( Eiadthong et al., 2000). This suggested a possibility that GISH analysis can be effectively used in the classification of Mangifera species.     

The influence of the topographic position within highlands of Western Rwanda on the interactions between banana (Musa spp. AAA-EA), parasitic nematodes and soil factors

Soil properties vary according to the topography. They affect water uptake and root exploration in the soil. Consequently, they may also influence the spread of plant–parasitic nematodes. This study reports on the effect of toposequence-related variations in soil on banana yields, foliar nutrient status, and nematode impact. Twenty banana plots were visited within 6 hills/valleys at each of the three toposequence positions: valley bottom, mid-slope and crest. Important variability in plant growth, nutrition and soil properties was observed within the toposequence. Significantly better plant growth (height and girth) was observed in the valley bottoms, where banana bunch weight was 1.7–3.4 kg higher (although not significant) than at upper toposequence positions. Best plant growth was observed in valley bottoms in contrast to the highest N and K foliar deficiencies in this position. Plants in the valley bottoms had higher foliar Ca and Mg, and K compared to those in the crest. Plants in the mid-slope had greater percentage of dead roots (19.1%), compared to the plants in the valley bottoms (12.3%) and the crest (14.2%). Soils in the valley bottoms were deeper, sandier, with lower organic matter, lower N, and K compared to the soils at higher toposequence. Nematodes likely play a key role in banana root damage, however, their effect appear to be in relation to various soil factors at each position. The abundance of Pratylenchus goodeyi had generally limited impact on banana yields in fields having less than 5% slope (crest and valley bottom) where soil conditions were more optimal for root growth. However, in the presence of increased run-off on steeper middle slopes, root death was increased even under moderate pressure from P. goodeyi.     

The conjunctive use of compost tea and inorganic fertiliser on the growth,yield and terpenoid content of Centella asiatica (L.) urban

The conjunctive use of a compost tea (CT) and an inorganic fertiliser (NPK) on the growth, yield and terpenoid content of Centella asiatica (L.) urban was evaluated. CT and NPK applied at half the recommended concentration resulted in the significant enhancement of vegetative growth, yield and antioxidant content. The synergistic effect of CT₅₀ and NPK₅₀ was highly pronounced on the bioactive components Asiatic acid, madecassoside and asiaticoside. The distribution of the total antioxidants was highest in roots (80%), followed by leaves (66%) and petioles (54%). There was a strong positive correlation (r = 0.990) between fertility and total antioxidant content, suggesting an enhanced synthesis of bioactive components resulting from the treatment. This response by C. asiatica to the integrated experimental treatment suggests a viable option for the commercial cultivation of the herb. Augmenting the vegetative biomass production and bioactive components will increase the availability of this medicinal herb for the treatment of various human ailments.     

Effect of high temperature stress on the reproductive growth of strawberry cvs. ‘Nyoho’ and ‘Toyonoka’

High temperatures are known to reduce fruit size and fruit weight in strawberry, but cultivar differences in the response to high temperature stress during the reproductive stage up to the second inflorescence have not been sufficiently reported. We examined the effect of two day/night temperature regimes on fruit set and fruit growth in two cultivars, ‘Nyoho’ and ‘Toyonoka’. A high day/night temperature of 30/25 °C reduced the number of inflorescences, flowers, and fruits in both cultivars compared with plants grown at 23/18 °C. The percentage of fruit set in ‘Nyoho’ was not significantly different between the two temperature treatments, while that in ‘Toyonoka’ was much lower at 30/25 °C than at 23/18 °C. Days to ripening was shorter at 30/25 °C than at 23/18 °C, and no cultivar differences were observed. Fresh weight of primary, secondary, and tertiary fruits was greater at 23/18 °C than at 30/25 °C in both cultivars, and no cultivar differences were observed, except in tertiary fruits. The diameter of fruits from all positions was also reduced at 30/25 °C in both cultivars. Relative growth rates of fruits showed two peaks in both cultivars and in both temperature treatments. Both peaks appeared earlier at 30/25 °C than at 23/18 °C. Percentage of fruit set at 30/25 °C in the second inflorescence was also significantly lower in ‘Toyonoka’ than in ‘Nyoho’. These results indicate that high temperature stress negatively affects the reproductive process in strawberry and that plant response to high temperature stress is cultivar-related in such responses.     

Canopy profiles of starch and leaf mass per area in greenhouse tomato and the relationship with leaf area and fruit growth

Better knowledge of patterns of carbon allocation in plants growing in CO₂-supplemented atmospheres may help to guide more efficient management of CO₂ applications in tomato greenhouses. Leaf starch and LMA (leaf mass per unit area) were investigated in commercially grown greenhouse tomato plants to determine the distribution and influence of leaf area and fruit load on these measures.