Growth Of Apple Trees Research Articles

Revealing critical mechanisms of BR-mediated apple nursery tree growth using iTRAQ-based proteomic analysis

Brassinosteroid is identified as an important hormone. However, information about brassinosteroid has not been fully elucidated, and few studies concerned its role in apple. The aim of this work was to study the role of brassinosteroid for apple tree growth. In our study, the effect of brassinosteroid on apple nursery tree was analyzed. The biomass, cell size and xylem content of apple nursery tree were obviously evaluated by brassinosteroid treatment; mineral elements contents, photosynthesis indexes, carbohydrate level and hormone contents were significantly high in brassinosteroid treated trees. To explore the molecular mechanisms of these phenotypic differences, iTRAQ-based quantitative proteomics were used to identify the expression profiles of proteins in apple nursery tree shoot tips in response to brassinosteroid at a key period (14days after brassinosteroid treatment). A total of 175 differentially expressed proteins were identified. They were mainly involved in chlorophyII biosynthesis, photosynthesis, carbohydrate metabolism, glycolysis, citric acid cycle, respiratory action, hormone signal, cell growth and ligin metabolism. The findings in this study indicate that brassinosteroid mediating apple nursery tree growth may be mainly through energy metabolism. Important biological processes identified here can be useful theoretical basis and provide new insights into the molecular mechanisms of brassinosteroid. Biological significanceBrassinosteroid is very important for plant growth and development. However, the molecular mechanism of brassinosteroid mediating growth process is not perfectly clear in plant, especially in apple nursery tree. We used a combination of physiological and bioinformatics analysis to investigate the effects of brassinosteroid on apple nursery tree growth and development. The data reported here demonstrated that brassinosteroid regulates apple nursery tree growth mainly through energy metabolism. Therefore it can provide a theoretical basis from energy points for developing dwarfed or compact apple trees. This will benefit for low orchard management cost as well as early bearing, and high fruit yield as well as quality.

Root pruning and prohexadione-calcium affect shoot growth of mature vertical axis apple trees

Root pruning and prohexadione-calcium affect shoot growth of mature vertical axis apple trees

Effects of apple fruit fermentation (AFF) solution on growth and fruit quality of apple trees

It has been demonstrated that the use of organic materials in fruit orchards can effectively increase soil fertility, fruit production and fruit quality. Insect and disease damage, crop thinning, natural drop cause abscission and abscised parts are a source of organic additives for orchard production. In this study, we developed a fermented nutrient solution composed of young apple fruits, brown sugar, a fermenting agent and water. Diluted solutions (1:100 and 1:200) of this nutrient solution were sprayed on 2-year-old and 12-year-old apple (Malus domestica (Borkh.) ‘Fuji’) trees. The results showed that foliar spraying of the fermentation solutions significantly improved tree height, trunk circumference, shoot growth and leaf area of young apple trees, and increased the fruit weight, shape index, firmness, soluble solid content, volatile compound content and vitamin C content of adult apple trees, as compared to the control treatment. The effects of the 1:200 diluted nutrient solution were significantly greater than those of the 1:100 diluted nutrient solution. Foliar spray of a nutrient solution derived from young apple fruit promoted vegetative growth and fruit quality.

Alternative Fertility Management for Establishing New Apple Orchards in the Mid-Atlantic

In the Mid-Atlantic, mineral nitrogen (N) fertilizers are applied in high-density apple (Malus ×domestica Borkh.) orchards to increase tree vegetative growth and achieve earlier fruiting. However, when applied in excess of plant needs, N fertilizer applications are an unnecessary expense and may lead to N leaching and groundwater pollution. Therefore, it is necessary to develop orchard fertilization programs that simultaneously provide adequate crop nutrition and minimize N loss into the environment. Nitrogen was applied in each of 3 years to newly planted ‘Red Delicious cv Schlect’/‘M.26’ trees at 67 kg N/ha/year in six fertilizer treatments: 1) two equal applications of granular calcium nitrate [Ca(NO3)2]; 2) chicken litter compost; 3) yardwaste compost; 4) a combination of chicken litter compost and granular Ca(NO3)2 with equal amounts of N from each fertilizer; 5) a combination of yardwaste compost and granular Ca(NO3)2 with equal amounts of N from each fertilizer; and 6) fertigation which consisted of eight weekly applications of solubilized Ca(NO3)2. Nonfertilized trees served as the control. In the third year of this experiment, the two chicken litter compost treatments had the greatest soil extractable P, the yardwaste compost treatment had the greatest soil extractable K, both full-rate compost treatments had greater soil extractable Mg than the other treatments, and all four compost treatments had greater soil extractable Mn than the treatments without compost. The four compost treatments also had greater soil extractable Ca and B than treatments without compost. By the third year of the experiment, the four compost treatments also had greater soil organic matter (OM) and soil C (with the integrated chicken litter compost treatment having similar soil C to the other treatments). Potentially mineralizable nitrogen and soil microbial biomass were similar among the treatments over the course of this experiment. The full rate chicken litter compost treatment and both yardwaste compost treatments had greater soil microbial respiration in 2015. The fertigation treatment performed similarly to the treatment where Ca(NO3)2 was applied as a granular product to the soil. Treatment differences found for the soil properties did not translate to increased tree size or leaf N content, suggesting that the trees were able to acquire sufficient N from the soil under all of the treatments. Our results suggest that applying fertilizers to fine textured soil with relatively high OM may not increase apple tree growth or productivity within the first 3 years after planting. In addition, compost applications can improve many soil properties, but these differences may not result in improved orchard productivity within 3 years.

Differential Proteomic Analysis Reveals the Effect of Calcium on Malus baccata Borkh. Leaves under Temperature Stress.

In the cool apple-producing areas of northern China, air temperature during early spring changes in a rapid and dramatic manner, which affects the growth and development of apple trees at the early stage of the growing season. Previous studies have shown that the treatment of calcium can increase the cold tolerance of Malus baccata Borkh., a widely-used rootstock apple tree in northern China. To better understand the physiological function of calcium in the response of M. baccata to temperature stress, we analyzed the effect of calcium treatment (2% CaCl2) on M. baccata leaves under temperature stress. Physiological analysis showed that temperature stress aggravated membrane lipid peroxidation, reduced chlorophyll content and induced photo-inhibition in leaves, whereas these indicators of stress injuries were alleviated by the application of calcium. An isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics approach was used in this study. Among the 2114 proteins that were detected in M. baccata leaves, 41, 25, and 34 proteins were differentially regulated by the increasing, decreasing, and changing temperature treatments, respectively. Calcium treatment induced 9 and 15 proteins after increasing and decreasing temperature, respectively, in comparison with non-treated plants. These calcium-responsive proteins were mainly related to catalytic activity, binding, and structural molecule activity. Hierarchical cluster analysis indicated that the changes in abundance of the proteins under increasing temperature and changing temperature treatments were similar, and the changes in protein abundance under decreasing temperature and increasing temperature with calcium treatment were similar. The findings of this study will allow a better understanding of the mechanisms underlying the role of calcium in M. baccata leaves under temperature stress.

Activated-Lignite-Based Super Large Granular Slow-Release Fertilizers Improve Apple Tree Growth: Synthesis, Characterizations, and Laboratory and Field Evaluations.

In this work, lignite, a low-grade coal, was modified using the solid-phase activation method with the aid of a Pd/CeO2 nanoparticle catalyst to improve its pore structure and nutrient absorption. Results indicate that the adsorption ability of the activated lignite to NO3-, NH4+, H2PO4-, and K+ was significantly higher than that of raw lignite. The activated lignite was successfully combined with the polymeric slow-release fertilizer, which exhibits typical slow-release behavior, to prepare the super large granular activated lignite slow-release fertilizer (SAF). In addition to the slow-release ability, the SAF showed excellent water-retention capabilities. Soil column leaching experiments further confirmed the slow-release characteristics of the SAF with fertilizer nutrient loss greatly reduced in comparison to traditional and slow-release fertilizers. Furthermore, field tests of the SAF in an orchard showed that the novel SAF was better than other tested fertilizers in improve the growth of young apple trees. Findings from this study suggest that the newly developed SAF has great potential to be used in apple cultivation and production systems in the future.

만개기 단근처리를 통한 수분스트레스가 '후지'/M.9 사과나무의 수체반응 및 과실특성에 미치는 영향

본 시험은 5~6월 수분스트레스가 사과나무의 광합성, 신초생장 및 과실품질에 미치는 영향을 구명하고자 실시하였다. 단근은 만개기(4월 30일)에 원줄기에서 30cm와 60cm 떨어진 곳에서 열 방향에 따라 양쪽 혹은 한쪽으로 처리 하였다. 무처리구의 5~6월 오후 평균 잎수분포텐셜은 -1.80MPa 이상을 유지하였지만, 단근 처리구들은 -1.80MPa 이하였다. 단근 처리 정도에 따른 5~6월경 오후 평균 잎 수분포텐셜은 양쪽 30cm 단근구(-2.06MPa), 양쪽 60cm 단근구(-2.02MPa), 한쪽 30cm 단근구(-1.91MPa) 순으로 낮았다. 한쪽 30cm 단근 처리와 양쪽 30cm 단근 처리는 5~6월 광합성속도를 각각 무처리구의 80% 및 65% 수준으로 감소시켰다. 또한, 한쪽 30cm 단근구의 무처리구 대비 총 신초장과 평균 과중의 감소 정도는 각각 25% 및 11% 정도였던 반면에 양쪽 30cm 단근구는 각각 45% 및 15% 정도였다. 그러나 가용성 고형물 함량 및 착색 정도는 단근 처리구들이 무처리구보다 높았으며, 양쪽 단근구들이 한쪽 단근구보다 더 높았다. 결론적으로, 5~6월 오후 평균 잎 수분포텐셜이 -1.80MPa 이하이면 과실비대가 감소되었고, -2.00MPa 이하이면 신초생장이 감소되었다. This study was conducted to find out the influence of water stress from May to June on photosynthesis, shoot growth and fruit quality of apple trees. Fuji'/M.9 apple trees were root pruned at full bloom (30th April), parallel to the row of 30 cm or 60 cm from the trunk, to one side or both sides of trunk. The average value of afternoon leaf water potential from May to June of the no root pruning was maintained over -1.80 MPa, but that of root-pruning treatments was maintained under -1.80 MPa. In the comparison of average value of leaf water potential from May to June by root-pruning degree, the root pruning both sides at 30 cm from trunk was lowest (-2.06 MPa), followed by the root pruning both sides at 60 cm (-2.02 MPa) and the root pruning one side at 30 cm (-1.91 MPa). Root pruning one side at 30 cm or both sides at 60 cm reduced photosynthetic rate from May to June by 80% or 65%, respectively, compared with no root pruning. So, the degree of decreasing total shoot length or average fruit weight compare to the no root pruning of the root pruning one side at 30 cm was 25% or 11%, respectively, and those of the root pruning both sides at 30 cm was 45% or 15%, respectively. However, the soluble solid content and fruit color of the root pruning was higher than those of the no root pruning, and those of the root pruning both sides was higher than root pruning one side. These results indicate that the fruit enlargement was decreased when the average value of average leaf water potential from May to June was under -1.80 MPa, and the shoot growth was decreased when that was under -2.00 MPa.

Effects of polyacrylamide on soil erosion and soil nutrient loss in sloped apple orchards.

In order to improve the soil environment, reduce soil erosion and soil nutrient loss, and explore the suitable dry broadcasting rate of polyacrylamide (PAM) in sloped apple orchard, experiments of different dry broadcasting rates of polyacrylamide were carried out in apple orchards with a slope of 20° in the hilly-gully region of northern Shaanxi from 2010 to 2012. PAM treatment levels included 0, 0.6, 0.8, 1.0, 1.2, 1.4 and 1.6 g·m-2. Surface runoff, eroded sediment, soil nutrient loss, and the growth of apple trees were monitored. Results showed that the surface runoff and runoff yield times from May to July exhibited a "V" shape with the increase of PAM application rate, and reached a minimum at the 1.0 g·m-2 level. However, the sediment yield decreased with increasing the PAM application rate. The concentrations of the ammonium nitrogen, available phosphorus, and available potassium in surface runoff and sediment decreased with increa-sing the PAM application rate. PAM significantly reduced the content of nitrate nitrogen in surface runoff, whereas it had no significant effect on nitrate nitrogen in sediment. Organic matter, total nitrogen, total phosphorus, and total potassium in the sediment decreased with increasing the PAM application rate. Moreover, PAM improved average fruit mass and fruit yields in sloped orchards, but it had no significant effect on the growth of apple trees and apple fruit flavor. An application le-vel of PAM at 1.0 g·m-2 should be suitable in sloped apple orchards.

The establishment of apple orchards as temperate forest garden systems and their impact on indigenous bacterial and fungal population abundance in Southern Ontario, Canada

AbstractThis research investigated soil microbial abundances affected by different ground management systems in establishing apple (Malus domestica cv. Idared, M9) orchards in Ontario, Canada. Four treatments, including forest garden systems with and without compost (FGSC and FGS), and grass understory systems with and without compost (GC and G), were assessed over two establishment years for gene copy abundance of soil arbuscular mycorrhizal (AM) fungi, total fungi and total bacteria using quantitative real-time polymerase chain reactions. Time had a greater effect on all three soil microbial abundances, with total bacterial and AM fungi decreasing and total fungal abundance increasing from spring 2013 to fall 2014. The changes were greatest between the sampling dates of fall 2013 and spring 2014, which is 1 yr after the establishment of the experimental apple plots. There were no significant differences in soil microbial abundances between treatments at any specific sampling date. Apple tree trunk circumference was greatest for FGSC and FGS after 2 yr, but no significant differences in GC and G treatments. In the last sampling period, fall 2014, FGSC plots had significantly greater trunk circumferences compared with G plots. Soil chemical properties neither changed over the 2 yr, nor did they differ between treatments at any one sampling time. We conclude that the apple-based FGS treatments can benefit apple tree growth and there is a basis for future research to explore specific plant–plant, plant–microbe and microbe–microbe relations in FGSs.

Prolonged Soil Frost Affects Hydraulics and Phenology of Apple Trees.

Restoration of an adequate water supply in spring is a prerequisite for survival of angiosperm trees in temperate regions. Trees must re-establish access to soil water and recover xylem functionality. We thus hypothesized that prolonged soil frost impairs recovery and affects hydraulics and phenology of Malus domestica var. ‘Golden Delicious.’ To test this hypothesis, over two consecutive winters the soil around some trees was insulated to prolong soil frosting, From mid-winter to early summer, the level of native embolism, the water and starch contents of wood, bark and buds were quantified at regular intervals and findings correlated with various phenological parameters, xylogenesis and fine root growth. The findings confirm that prolonged soil frost affects tree hydraulics and phenology but the severity of the effect depends on the climatic conditions. In both study years, percentage loss of hydraulic conductivity (PLC) decreased from about 70% at the end of winter to about 10% in May. Thereby, xylem refilling strongly coincided with a decrease of starch in wood and bark. Also treated trees were able to restore their hydraulic system by May but, in the warm spring of 2012, xylem refilling, the increases in water content and starch depolymerization were delayed. In contrast, in the cold spring of 2013 only small differences between control and treated trees were observed. Prolongation of soil frost also led to a delay in phenology, xylogenesis, and fine root growth. We conclude that reduced water uptake from frozen or cold soils impairs refilling and thus negatively impacts tree hydraulics and growth of apple trees in spring. Under unfavorable circumstances, this may cause severe winter damage or even dieback.

Characterization of an Autophagy-Related Gene MdATG8i from Apple.

Nutrient deficiencies restrict apple (Malus sp.) tree growth and productivity in Northwest China. The process of autophagy, a conserved degradation pathway in eukaryotic cells, has important roles in nutrient-recycling and helps improve plant performance during periods of nutrient-starvation. Little is known about the functioning of autophagy-related genes (ATGs) in apple. In this study, one of the ATG8 gene family members MdATG8i was isolated from Malus domestica. MdATG8i has conserved putative tubulin binding sites and ATG7 interaction domains. A 1865-bp promoter region cloned from apple genome DNA was predicated to have cis-regulatory elements responsive to light, environmental stresses, and hormones. MdATG8i transcriptions were induced in response to leaf senescence, nitrogen depletion, and oxidative stress. At cellular level, MdATG8i protein was expressed in the nucleus and cytoplasm of onion epidermal cells. Yeast two-hybrid tests showed that MdATG8i could interact with MdATG7a and MdATG7b. In Arabidopsis, its heterologous expression was associated with enhanced vegetative growth, leaf senescence, and tolerance to nitrogen- and carbon-starvation. MdATG8i-overexpressing “Orin” apple callus lines also displayed improved tolerance to nutrient-limited conditions. Our results demonstrate that MdATG8i protein could function in autophagy in a conserved way, as a positive regulator in the response to nutrient-starvation.

Crescimento inicial, produção e qualidade de frutos de macieiras submetidas a irrigação e fertirrigação

This study aimed to evaluate nutrient content on leaves and fruit flesh, yield and quality of fruits, as well as apple tree growth as affected by the fertilizer physical form (conventional or fertirrigation) and water addition or not via irrigation. The experiment was carried out in Sao Joaquim, Southern of Brazil, during the 2012/2013 and 2013/2014 growing season. The orchard was planted in 2011 with ‘Kinkas’ cultivar grafted over a Marubakaido rootstock, 1.666 trees ha-1. The eight replications of each treatment were allocated in the completely randomized block design. Treatments consisted of conventional solid soil fertilization (T1), irrigation + conventional solid soil fertilization (T2), irrigation + fertirrigation (T3), and fertirrigation (T4). From the daily averages of tensiometer readings in addition to the water soil retention the irrigation needs and the application time curve were determined. In 2012, 27 kg ha-1 of N was applied; in the following season, it 100 kg ha-1 of N and 150 kg ha-1 of K2O was applied. Fertilizers were split three times on treatments T1 and T2, and six times on treatments T3 and T4, from November through January. During the experimental period it many drought periods were observed. Irrigation and fertirrigation had no effect on initial apple tree growth. Irrigation did not affect the nutrient content in leaves or fruit flesh. Fruits from the T1 treatment had higher firmness than fruits from the other treatments. Fruits from T3 (irrigation + fertirrigation) presented the highest weight. Fruit yield, however, did not differ among treatments. Fertirrigation was the best form of nutrient application to the plants, but it is necessary to determine rates and times of application to obtain the maximum productive efficiency.

The effect of rootstock on apple tree bearing stability in a cooler climate

The effect of rootstock on apple yield, productivity and alternate bearing was investigated at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry during a six-year period in a full bearing orchard. Apple cultivars ‘Ligol’ and ‘Auksis’ grafted on M.26 semi-dwarf rootstock; M.9, B.396, P 66, P 67 and Pure 1 dwarf rootstocks; and P 59, P 22, P 61, P 62 and PB.4 super-dwarf rootstocks were tested. Rootstock had a significant effect on apple tree growth, average yield and cumulative yield efficiency. Alternate apple bearing did not depend on rootstock vigour. Constant correlations between bearing regularity, average yield and cumulative yield efficiency were not established and differed on a cultivar or rootstock level. On the average of both tested cultivars, a more regular apple yield was recorded on Pure 1, P 59 and B.396 rootstocks. A significantly higher alternate bearing index was established on P 67, P 62 and M.9 rootstocks.

Nutrition, productivity and soil chemical properties in an apple orchard under weed management

Weed management in orchard may affect apple tree nutritional status and yield, N flow and other soil chemical properties. This study evaluated apple tree nutritional status and yield, N flow in soil and soil chemical properties in an apple orchard under different weed managements. The experiment was started in October 2011 in an apple orchard established in 2008, on 80 plants submitted to the following treatments: no weed management, weed desiccation in rows, weed mowing in rows and weed mowing in rows and inter-rows. In 2011/2012, 2012/2013, and 2013/2014 crop seasons, stem diameter, number of fruits per plant and yield were measured, and nutrient leaf concentrations were quantified. In 2012/2013 and 2013/2014 crop seasons, soil samples were collected from 0 to 0.20 m layers, in order to quantify NH4 +–N and NO3 −–N. In September 2013, 24 months after beginning of the experiment, stratified soil samples were collected in the 0–0.025, 0.025–0.05, 0.05–0.10, 0.10–0.15, 0.15–0.20 and 0.20–0.40 m layers. Soil total organic carbon, pH, available P and exchangeable K, Ca, and Mg were measured. The weed management methods did not affect apple tree yield and growth and they had a small effect on nutrient concentrations in leaves and in soil. Row and inter-row weed management had little or no effect on competition with apple trees for water and nutrients. The weed management can be dispensed during the production cycle, reducing soil erosion, N losses and the use of herbicides.

Resistance Inducers and Plant Growth Regulators Show Only Limited and Transient Effects on Infection Rates, Growth Rates and Symptom Expression of Apple Trees Infected With ‘candidatus Phytoplasma mali’

The effects of four commercially available bio-active compounds on the infection rates, symptom expression and growth rates of apple trees (Malus × domestica Borkh.) cv. Golden Delicious infected with ‘Candidatus Phytoplasma mali’ (the so-called Apple Proliferation phytoplasma or AP) were tested over a three-year period under controlled conditions. Post-infection treatments using Bion® (active ingredient: Acibenzolar-S-Methyl), Messenger® (Harpin protein), Regalis® (Prohexadione-Ca) and Dormex® (Cyanamide) had no significant effect on infection rates. Terminal growth of apple trees (grown as one-shoot pruned trees) was increased significantly by AP infection; Prohexadione-Ca was the only compound which had a significant (inhibiting) effect on the growth of both infected and non-infected apple trees. Acibenzolar-S-Methyl and Harpin had no significant effects on symptom expression. AP symptoms were masked during summer by Prohexadione-Ca, which caused severe growth abnormalities. Cyanamide changed the seasonal appearance of AP symptoms: while symptoms were delayed compared to the untreated control the first two years (2008 and 2009), symptoms appeared earlier the third year (2010). Differences in symptom expression levelled off later in the vegetative season, and no significant difference was found in October.

Transcription Profiles Reveal Sugar and Hormone Signaling Pathways Mediating Flower Induction in Apple (Malus domestica Borkh.).

Flower induction in apple (Malus domestica Borkh.) is regulated by complex gene networks that involve multiple signal pathways to ensure flower bud formation in the next year, but the molecular determinants of apple flower induction are still unknown. In this research, transcriptomic profiles from differentiating buds allowed us to identify genes potentially involved in signaling pathways that mediate the regulatory mechanisms of flower induction. A hypothetical model for this regulatory mechanism was obtained by analysis of the available transcriptomic data, suggesting that sugar-, hormone- and flowering-related genes, as well as those involved in cell-cycle induction, participated in the apple flower induction process. Sugar levels and metabolism-related gene expression profiles revealed that sucrose is the initiation signal in flower induction. Complex hormone regulatory networks involved in cytokinin (CK), abscisic acid (ABA) and gibberellic acid pathways also induce apple flower formation. CK plays a key role in the regulation of cell formation and differentiation, and in affecting flowering-related gene expression levels during these processes. Meanwhile, ABA levels and ABA-related gene expression levels gradually increased, as did those of sugar metabolism-related genes, in developing buds, indicating that ABA signals regulate apple flower induction by participating in the sugar-mediated flowering pathway. Furthermore, changes in sugar and starch deposition levels in buds can be affected by ABA content and the expression of the genes involved in the ABA signaling pathway. Thus, multiple pathways, which are mainly mediated by crosstalk between sugar and hormone signals, regulate the molecular network involved in bud growth and flower induction in apple trees.

Impact of cover crop in pre-plant of apple orchards: relationship between crop health, root inhabiting fungi and rhizospheric bacteria

Manici, L. M., Kelderer, M., Caputo, F., Nicoletti, F., De Luca Picione, F. and Topp A. R. 2015. Impact of cover crop in pre-plant of apple orchards: relationship between crop health, root inhabiting fungi and rhizospheric bacteria. Can. J. Plant Sci. 95: 947–958. Replant disease of fruit tree orchards has a multifactorial etiology, mainly due to the decline in soil biodiversity along with an increase in root rot pathogens, which can be principally countered with appropriate cropping practices. Therefore, a study on the impact of cover crops on plant health of young fruit trees in long-term orchards was performed. Bioassays were performed over two consecutive growing cycles using soil from a multigeneration apple orchard affected by replant disease. First, a cycle was performed with three cover crops (alfalfa, barley, marigold) and apple rootstock plantlets; at the end, the above-ground part of the plant was removed and root residues left in the soil. In the second cycle, an apple orchard planting was simulated upon the first experimental design. Changes of diversity and composition of root inhabiting fungi and rhizospheric bacteria were evaluated as well as apple plant growth response to the pre-plant treatments. Results suggest that one cycle with alternate plants was sufficient to induce changes at the rhizosphere level, despite soil microbial resilience caused by the same long-term soil management. Rhizospheric bacteria were generally affected by plant genotype. Findings suggest that all three different cover crops can harbor almost all fungal species that colonize apple in replanted orchards (Fusarium spp., Pythum spp., binucleate Rhizoctonia sp., Cylindrocarpon-like-fungi and a several nonpathogenic saprophytic fungi named “other”), but their infection frequency varied according to the host plant. A single pre-plant break treatment did not overall differ significantly in plant growth of subsequent apple tree; however, break with marigold, which increased abundance of nonpathogenic root inhabiting fungi more than other cover crops, gave significantly higher plant growth than obtained after barley. This study provides evidence about cover-crop potential to increase soil diversity in long-term permanent cropping systems and to manipulate root colonizing fungi involved in crop health.

Characteristics of Dried Soil Layers Under Apple Orchards of Different Ages and Their Applications in Soil Water Managements on the Loess Plateau of China

Negative soil water balance (i.e., water input < water output) can lead to soil desiccation and subsequently the occurrence of a dried soil layer (DSL). The DSLs are generally studied at a specific sampling depth (e.g., 500 cm), and the actual extent of DSLs remains unknown due to the challenge of collecting deep soil samples. To investigate the characteristics of actual DSLs under different ages of apple orchards and ascertain the optimal age of apple orchards for avoiding/controlling the formation of DSLs, soil samples were collected to a depth of 1 800 cm under apple orchards of different ages in Changwu on the Loess Plateau of China. As the ages increased, soil water content (SWC) and mean SWC in DSLs showed an overall decreasing trend, whereas while DSL thickness and the quantity of water deficit (QWD) in DSLs demonstrated an increasing trend. The DSL was the thickest (1 600 cm) under the 17-year-old orchard, the forming velocity of DSL thickness was the highest at the apple tree growth stage of 9–17 years (168 cm year−1), and the highest increasing velocity of QWD (–181 mm year−1) was also observed at this stage. The thickness of DSL was significantly correlated with growth age and root depth of apple trees (r > 0.88), whereas the QWD and mean SWC in DSLs were found to have no correlation with them. The optimal age of apple orchards for avoiding/controlling the formation of DSLs was about 9 years. This information provided pertinent references for the management of deep water resources by controlling the growth age of plants.

EduAPPLE: Interactive Teaching Tool for Apple Tree Crown Formation

In central Europe there are many backyard fruit growers who receive no proper education about fruit tree care. Their knowledge is mostly based on various handbooks and learning through trial and error. Such learning is slow and can even result in damage to the tree. To shorten the learning time, a new interactive teaching tool EduAPPLE has been developed based on the basic laws of apple tree (Malus ×domestica) growth and training. Pruning, weighting, tying, and spreading can be interactively practiced over and over again without any danger to the actual trees. Training responses are immediately seen and are analogous to those of real trees. They are not only predetermined by a set of rules, but also calculated based on the changes the actions cause to the light interception of the tree. EduAPPLE enables high-quality views of trees and their light interception from all angles in real time and is designed for education regarding free-standing apple tree training (spindle). It can, therefore, be used in schools, universities, and other educational organizations, as well as by tree growers, including the large number of growers having only a few fruit trees.

The effect of methyl jasmonate and acibenzolar-S-methyl on the populations of the European red mite (Panonychus ulmi Koch) and Typhlodromus pyri Scheut. in apple orchards, as well as on the yield and growth of apple trees

The aim of the study was to examine the possibility of applying methyl jasmonate (JA-Me) and acibenzolar-S-methyl (BTH) to reduce the population of mites in apple orchards. The experiment was performed on apple trees cv. “Golden Delicious” grown in an orchard according to Integrated Pest Management (IPM) principles. The study showed that of the two elicitors, JA-Me restricted the population of the European red mite (Panonychus ulmi Koch) more strongly than BTH. Neither of these compounds significantly affected the size of the population of Typhlodromus pyri Scheuten – a beneficial predatory mite feeding on spider mites in apple orchards. The study also showed no adverse effects of these compounds on the yield and growth of apple trees, nor on their reproduction as measured by seed production. Studies indicate that the use of methyl jasmonate against spider mites on apple trees can complement the use of conventional acaricides as well as the introduction of predatory mites of the family Phytoseiidae in the protection of apple orchards.