Effect of Various Citrus Rootstock-scion Combinations on Tree Growth,Fruit Quality,and Photosynthetic Characteristics under Red Loam Soil Conditions

[Objectives]To investigate the effects of 15 distinct citrus rootstock-scion combinations on tree growth,fruit quality,and photosynthetic characteristics under red loam soil conditions and provide a theoretical foundation for the selection of appropriate citrus rootstock-scion combinations in the Zhaoqing region.[Methods]A total of 15 citrus rootstock-scion combinations were utilized as test materials for a comprehensive analysis of their phenological periods(budding,flowering,and fruiting),tree growth indicators(tree height,crown diameter,and growth),and fruit quality(appearance quality and intrinsic quality).The photosynthetic characteristics of the test materials,including the net photosynthetic rate(Pn),transpiration rate(Tr),water use efficiency(WUE),apparent quantum yield(AQY),and carboxylation efficiency(CE),were analyzed to determine their significance.Additionally,the leaf photosynthetic physiological indicators,such as soluble protein,specific leaf weight,chlorophyll,and carotenoids,were evaluated.[Results]There were notable differences observed in the phenological period,growth potential of trees,fruit quality,and photosynthetic characteristics among various citrus rootstock-scion combinations.The phenological periods exhibited variation contingent on the grafting varieties.In terms of tree growth potential,the Citrus tangerina Tanaka‘Hongju’and C.haniana Hort.‘Suanju’rootstocks demonstrated greater tree height,crown growth,and overall tree strength;however,they were also prone to excessive growth.Conversely,the C.limonia Osbeck‘Hongningmeng’and C.sinensis×P.trifoliata‘Zhicheng’rootstocks displayed medium growth potential,while the Poncirus trifoliate(L)Raf.‘Zhike’rootstock resulted in shorter trees.In terms of fruit quality,the single fruit weight of C.flamea Hort.‘Shatangju’ranged from 33 to 50 g,exhibiting a flat and round shape.The total soluble solids and titratable acid content of‘Shatangju’grafted onto the‘Zhike’rootstock were notably high.In contrast,the single fruit weight of C.haniana Hort.‘Chuntianju’varied between 65 and 81 g,characterized by a high flat round shape.The‘Suanju’rootstock demonstrated a higher sugar and acid content compared to other rootstocks.Additionally,the single fruit weight of C.nobilis Lour.‘Gonggan’ranged from 62 to 145 g,with the fruit shape being either round or oval.The soluble sugar and total soluble solids content associated with the‘Zhike’rootstock was also elevated.In relation to photosynthetic characteristics,the photosynthetic performance of the‘Shatangju’variety was superior when grafted onto the‘Zhike’and‘Hongju’rootstocks.Similarly,the‘Chuntianju’variety exhibited enhanced photosynthetic performance on the‘Zhike’,‘Zhicheng’,and‘Hongju’rootstocks.Furthermore,the‘Gonggan’variety demonstrated improved photosynthetic performance when grafted onto the‘Zhike’and‘Suanju’rootstocks.[Conclusions]Based on the characteristics of the red loam soil in the Zhaoqing region,the rootstocks‘Zhike’and‘Hongju’are conducive to the cultivation of the‘Shatangju’variety.Additionally,the rootstocks‘Zhike’,‘Zhicheng’,and‘Hongju’are optimal for the growth of the‘Chuntianju’variety,while the rootstocks‘Zhike’and‘Suanju’are appropriate for the growth of the‘Gonggan’variety.

Improved observation of colonized roots reveals the regulation of arbuscule development and senescence by drought stress in the arbuscular mycorrhizae of citrus

Citrus is the typical mycorrhizal fruit tree species establishing symbiosis with arbuscular mycorrhizal (AM) fungi. However, arbuscule development and senescence in colonized citrus roots, especially in response to drought stress, remain unclear, which is mainly due to the difficulty in clearing and staining lignified roots with the conventional method. Here, we improved the observation of colonized roots of citrus plants with the sectioning method, which enabled the clear observation of AM fungal structures. Furthermore, we investigated the effects of one week of drought stress on arbuscule development and senescence with the sectioning method. Microscopy observations indicated that drought stress significantly decreased mycorrhizal colonization (F%and M%) although it did not affect plant growth performance. Fluorescence probes (WGA 488 and/or Nile red) revealed that drought stress inhibited arbuscule development by increasing the percentage of arbuscules at the early stage and decreasing the percentages of arbuscules at the midterm and mature stages. Meanwhile, drought stress accelerated arbuscule senescence, which was characterized by the increased accumulation of neutral lipids. Overall, the sectioning method developed in this study enables the in-depth investigation of arbuscule status, and drought stress can inhibit arbuscule development but accelerate arbuscule senescence in the colonized roots of citrus plants. This study paves the way to elaborately dissecting the arbuscule dynamics in the roots of fruit tree species in response to diverse abiotic stresses.

Advances in Molecular Regulatory Mechanisms of Fruit Trees under Low Temperature Stress

The most recent research findings on the tolerance of fruit trees to cold stress are reviewed from a molecular perspective,including the perception and transduction of low temperature calcium signaling,CBF-dependent molecular regulatory mechanisms,non-CBF-dependent molecular regulatory mechanisms,and so forth.The objective is to provide a reference basis for further improving the cold resistance of fruit trees and cultivating new varieties of hardy plants.

Influence of Fruit Tree Types and Arrangements on Yield, Quality and Economic Returns of Cotton of Intercropping System in Southern Xinjiang

[Objective] The aim was to provide a theoretical basis for stable and highly effective intercropping arrangements and scientific management measures by selecting apple, pear, peach, apricot, walnut, jujube and other fruit trees to study their influence on yield, fiber quality and economic returns of intercropped cotton in southern Xinjiang. [Method] Based on major cropping pattern in production, randomized block design was adopted to explore growth indicators, canopy micrometeorological indicators, yield and fiber quality in key growth stage. [Result] Shading has a significant effect on cotton canopy micro-environment and canopy diameter is proportional to shading effect. According to comparisons of the same tree type, the change of canopy micro-environment was as follows： under canopyouter canopymiddle points and peachpearapplewalnutjujube for comparisons among different tree types. Canopy diameter is directly proportional to the number of tree branch and boll weight reductions and shading is the main cause of yield reduction. The canopy expansion is the major cause of decline of light intensity, temperature and humidity of cotton canopy. [Conclusion] Fruit trees, which will promote cotton yield,quality and canopy-environment, are as follows： jujube walnut apple pear peach trees. In practice, trees, which are small in canopy or well trimmed, are popular in production, such as jujube trees, to improve cotton yield and fiber quality.

Growth simulation and yield prediction for perennial jujube fruit tree by integrating age into the WOFOST model

Mathematical models have been widely employed for the simulation of growth dynamics of annual crops,thereby performing yield prediction,but not for fruit tree species such as jujube tree(Zizyphus jujuba).The objectives of this study were to investigate the potential use of a modified WOFOST model for predicting jujube yield by introducing tree age as a key parameter.The model was established using data collected from dedicated field experiments performed in 2016-2018.Simulated growth dynamics of dry weights of leaves,stems,fruits,total biomass and leaf area index(LAI) agreed well with measured values,showing root mean square error(RMSE) values of 0.143,0.333,0.366,0.624 t ha^-1 and 0.19,and R2 values of 0.947,0.976,0.985,0.986 and 0.95,respectively.Simulated phenological development stages for emergence,anthesis and maturity were 2,3 and 3 days earlier than the observed values,respectively.In addition,in order to predict the yields of trees with different ages,the weight of new organs(initial buds and roots) in each growing season was introduced as the initial total dry weight(TDWI),which was calculated as averaged,fitted and optimized values of trees with the same age.The results showed the evolution of the simulated LAI and yields profiled in response to the changes in TDWI.The modelling performance was significantly improved when it considered TDWI integrated with tree age,showing good global(R2≥0.856,RMSE≤0.68 t ha^-1) and local accuracies(mean R2≥0.43,RMSE≤0.70 t ha^-1).Furthermore,the optimized TDWI exhibited the highest precision,with globally validated R2 of 0.891 and RMSE of 0.591 t ha^-1,and local mean R2 of 0.57 and RMSE of 0.66 t ha^-1,respectively.The proposed model was not only verified with the confidence to accurately predict yields of jujube,but it can also provide a fundamental strategy for simulating the growth of other fruit trees.

Determination of the Geographical Origin of Fruits by Using 26S rDNA Fingerprinting of Yeast Communities by PCR-DGGE： An Application to Shea Tree Fruits

International trade intensifies the process of globalization which has extended to the entire planet and extends to the entire planet. In view of the difficulties of installing these documentary systems in developing countries, in particularly the countries of sub-Saharan Africa, the new strategies of traceability emerge. Among the new tools of tracing the products of vegetable origin, a ＂biological code bar＂ based on the analysis of the DNA of micro-organisms present on the fruits is an interesting tool. A molecular technique employing 26S rDNA profiles generated by PCR-DGGE was used to detect the variation in yeast community structures of Shea tree fruits （Vitellaria paradoxa） from Senegal, Ghana and Mali. When the 26S rDNA profiles were analyzed by image analysis and multivariate analysis, distinct microbial communities were detected on Shea tree fruits. The band profiles of yeasts from different countries were specific for each location and could be used as a bar code to discriminate the origin of the fruits. This method is a new traceability tool which provides fruit products with an unique biological bar code and makes it possible to trace back the fruits to their original location.

Molecular Phylogeny of the “True Citrus Fruit Trees” Group (Aurantioideae, Rutaceae) as Inferred from Chloroplast DNA Sequence

The genus Citrus L. has a long controversial taxonomy history, and a well-resolved molecular phylogeny of the ＂true citrus fruit trees＂ group in the future will provide new information for advancing breeding techniques and developing better conservation strategies. In the present study, three cpDNA fragments （TrnL-TrnF, PsbH-PetB, and TrnS-TrnG） of 30 genotypes chosen from the six genera of the ＂true citrus fruit trees＂ group were analyzed. A molecular phylogenetic tree of the ＂true citrus fruit trees＂ group ＂~as reconstructed based on plastid DNA sequences. The results confirmed that the ＂true citrus fruit trees＂ group was monophyletic, and thereby the group was divided into genera as previously suggested based on morphological characters. The cpDNA data also suggested that Poncirus might be the first genus separated from the other five genera in the group. The genus Fortunella were of hybrid origin and Citrus might be as its putative paternal parent. The genera Microcitrus, Eremocitrus, and Clymenia were possibly monophyletic and their common ancestor might branch out from Citrus. Furthermore, the phylogenetic relationships within the Citrus genus were discussed.

Review on Effects of Nitrogen on the Internal Quality of Peach Fruit

On the basis of referring plenty of literatures, we summarized the research advance in effects of nitrogen on the internal quality of peach fruit. Most studies have shown that proper nitrogen application can improve internal quality of fruit, and excessive nitrogen application can reduce soluble solid and sugar contents of fruit, increase organic acid content, reduce fruit aroma, increase protein and amino acid contents, and increase or reduce vitamin C content. Relevant issues were discussed.

Review on Effects of Sunlight on the Internal Quality of Peach Fruit

On the basis of referring plenty of literatures, we summed up the research advance in effects of sun light on the internal quality of peach fruit. This paper discussed the effect of light on the internal quality of peach fruit under the conditions of open cultivation, protected cultivation, bagging and surface covering with reflective film, the mechanism of occurrence and the technical measures to improve the utilization rate of light and light energy, and prospected the future research work.

Elaboration and Characterization of Composite Materials Reinforced by Papaya Trunk Fibers (<i>Carica papaya</i>) and Particles of the Hulls of the Kernels of the Winged Fruits (<i>Canarium schweinfurthii</i>) with Polyester Matrix

In this work we determine the physical and mechanical properties of local composites reinforced with papaya trunk fibers (FTP) on one hand and particles of the hulls of the kernels of the garlic (PCNFA) in the other hand. The samples are produced according to BSI 2782 standards;by combining fibers and untreated to polyester matrix following the contact molding method. We notice that the long fibers of papaya trunks improve the tensile/compression characteristics of composites by 45.44% compared to pure polyester;while the short fibers improve the flexural strength of composites by 62.30% compared to pure polyester. Furthermore, adding fibers decreases the density of the final composite material and the rate of water absorption increases with the size of the fibers. As regards composite materials with particle reinforcement from the cores of the winged fruits, the particle size (fine ≤ 800 μm and large ≤ 1.6 mm) has no influence on the Young’s modulus and on the rate of water absorption. On the other hand, fine particles improve the flexural strength of composite materials by 53.08% compared to pure polyester;fine particles increase the density by 19% compared to the density of pure polyester.

Selection of promising chestnuts(Castanea sativa) among wild growing trees from southern Mediterranean region forests of Turkey

Turkey ranked third place in the world for chestnut production after China and South Korea and the country has unique chestnut forests including valuable and diverse chestnut genotypes. This study was conducted to select superior chestnut genotypes within seedling popu- lations found in natural wild grown chestnut forest located in Isparta province in Turkey during 2010-2011 years. A total of 2500 wild grown chestnut trees were examined on the field first year and among them the most promising 22 genotypes were chosen according to relatively high yield capacity, earliness, tolerance to chestnut blight （Cryphonectria parasitica）, ink disease （Phytopthora cambivora）, and fruit quality characteristics. The selected 22 genotypes were evaluated for their detailed morpho- logical, phenological and pomological traits in 2010 and 2011. According to average of 2 years, nut weight, the number of nut per kilogram, nut width, nut length, nut height and nut shell thickness of 22 promising genotypes ranged from 10.26 to 22.32 g, 97.47 to 44.80/kg, 26.80 to 42.47, 16.92 to 25.91, 27.74 to 39.73, and 0.26 to 1.01 mm, respectively. The ash, crude protein, and total fat content of kernels were between 0.85 to 1.94, 3.69 to 7.06 and 1.32 to 4.52, respectively. The genotypes were evaluated with weighted ranking method and the highest general quality score was observed in genotypes of IY17, IYO1, IY42, IY43 and IY12.

Method for the fruit tree recognition and navigation in complex environment of an agricultural robot

To realize the visual navigation of agricultural robots in the complex environment of orchards,this study proposed a method for fruit tree recognition and navigation based on YOLOv5.The YOLOv5s model was selected and trained to identify the trunks of the left and right rows of fruit trees;the quadratic curve was fitted to the bottom center of the fruit tree recognition box,and the identified fruit trees were divided into left and right columns by using the extreme value point of the quadratic curve to obtain the left and right rows of fruit trees;the straight-line equation of the left and right fruit tree rows was further solved,the median line of the two straight lines was taken as the expected navigation path of the robot,and the path tracing navigation experiment was carried out by using the improved LQR control algorithm.The experimental results show that under the guidance of the machine vision system and guided by the improved LQR control algorithm,the lateral error and heading error can converge quickly to the desired navigation path in the four initial states of[0 m,−0.34 rad],[0.10 m,0.34 rad],[0.15 m,0 rad]and[0.20 m,−0.34 rad].When the initial speed was 0.5 m/s,the average lateral error was 0.059 m and the average heading error was 0.2787 rad for the navigation trials in the four different initial states.Its average driving was 5.3 m into the steady state,the average value of steady state lateral error was 0.0102 m,the average value of steady state heading error was 0.0253 rad,and the average relative error of the robot driving along the desired navigation path was 4.6%.The results indicate that the navigation algorithm proposed in this study has good robustness,meets the operational requirements of robot autonomous navigation in orchard environment,and improves the reliability of robot driving in orchard.

Plantation of Fruit Tree and Its Application in Qiqihar’s Garden Greening

The sample survey methodology was used to investigate the concept of fruit trees planted in the Qiqihar City landscaping. The application effects of fruit trees in landscape were compared and the utilization features of fruit trees were analyzed. The most appropriate fruit trees species were selected and the optimum configuration types were proposed. The research results showed that from the perspective of the utilization of fruit tress in landscape in Qiqihar, the fruit trees species were not abundant and the quality was also not enough. The mostly used trees genera included Lonicera of Caprifoliaceae family, Viburnum, Sambucus, and Prunus, Ceraras, Pyrus, Malus belonging to Rosaceae family.

Application of Fruit Trees in Suzhou Classical Gardens

The application of fruit trees in four Suzhou classical gardens involving the Humble Administrator's Garden,the Lingering Garden,the Lion Forest Garden and the Garden of Cultivation was investigated. The result showed that:firstly,fruit trees had been widely applied in each garden;secondly,the number and species of fruit trees differed from garden to garden;thirdly,the management of fruit trees was poor,resulting in poor growth of plants. In view of these problems,corresponding suggestions had been put forward and meanwhile creative fruit trees' planting had been proposed in order to achiever better landscape effect.

Application of Fruit Trees in Urban Landscaping

By reviewing application history of fruit trees in gardens, application principles of fruit trees in urban garden landscapes were proposed in view of its landscape components, such as flower, fruit, foliage, figure and cultural connotations. Application principles included "right tree for right land", "fully playing ecological effects of fruit trees", "improving rhythmic sense and artistic quality of plant furnishings", and "using characteristic fruit trees". Its application in different garden green spaces such as by roadside, in residential districts, in parks, in sightseeing orchards was respectively analyzed, examples were given to show application range of different species. Finally, attentions were proposed to provide references for the future application of fruit trees in urban garden landscapes.

The historical and current research progress on jujube–a superfruit for the future

Jujube(Ziziphus jujuba Mill.),or Chinese date,is the most important species of Rhamnaceae,a large cosmopolitan family,and is one of the oldest cultivated fruit trees in the world.It originates from the middle and lower reaches of the Yellow River,the‘mother river’of the Chinese people.It is distributed in at least 48 countries on all continents except Antarctica and is becoming increasingly important,especially in arid and semiarid marginal lands.Based on a systematic analysis of the unique characteristics of jujube,we suggest that it deserves to be recognized as a superfruit.We summarized historical research achievements from the past 3000 years and reviewed recent research advances since 1949 in seven fields,including genome sequencing and application,germplasm resources and systematic taxonomy,breeding and genetics,cultivation theory and techniques,pest control,postharvest physiology and techniques,and nutrition and processing.Based on the challenges facing the jujube industry,we discuss eight research aspects to be focused on in the future.

Overview of Relation between Mineral Nutrient Elements and Growth and Development of Fruit Trees

Mineral nutrition is the material basis for growth and development,yield and quality of fruit trees. It exerts a great effect on the growth and development,fruit quality,yield,and resistance of fruit trees. On the basis of reading a large number of references both at home and abroad,this paper elaborated the relationship between mineral nutrient elements and growth and fruit yield and quality of fruit trees,so as to make proper fertilizer mixing,balance the fertilizer application,promote growth and development of fruit trees,and increase the yield of fruit trees and improve the fruit quality.

Economics of the plant species used in homestead agroforestry on an offshore Sandwip Island of Chittagong District, Bangladesh

This study was performed in five villages of Sandwip Upazila, Chittagong district with a view to identify the tree resources, utilization pattern and economic return of major fruit and timber tree species. Information collected from a total of 60 households ranging from marginal, small, medium and large categories. Number of plant species increased with the increase of homestead area. A total of 33 plant species were recorded from the homegarden, of which 19 were fruit and 14 were timber tree species. Considerable number of vegetables was also planted under the shade of the homestead trees. The investment analysis showed that average benefit-cost ratios were greater than one, net present values were positive and internal rate of returns were more than 10%. Long term investment on horticulture and timber tree species is highly profitable if species like Artocarpus heterophyllus, Cocos nucifera, Tectona grandis and Swietenia macrophylla are planted.

Analysis of Meteorological Conditions during the Blossom Period of Apple and Peach in Haiyang City

Through observing the phenology of two kinds of fruit trees,apple and peach trees,during their flowering periods in the past seven years,the meteorological conditions in the flowering stages were analyzed and summarized in this paper.The late frost weather situation occurred in late April in Haiyang City also was elaborated in the paper.According to the data analysis,the terrain effect had induced a large temperature differences between north and south in April in Haiyang.Early flowering of fruit trees is as early as 5 to 8 days in the northern region than that in the southern region;accumulated temperature which was greater than or equal to 0 ℃ and the date of the temperature stably through a boundary,were the important meteorological indicators of the fruit trees' early flowering.The late frost in mid-late April is meteorological disasters of the fruit trees flowering period.The weather background of the occurred late frost,the disaster reasons and the measures for the prevention of late frost were proposed.

Study on Curative Effect of Perforated Injection of Zinc-ammonia Complex on Rosette Disease of Fruit Tree

[ Objective ] The paper was to explore a kind of zinc preparation suitable for injection on trees with fast, efficient and safe cure effect on physiological disease of zinc deficiency. [Method] Taking three years old apple, pear, peach and grape trees as the materials, the author studied the absorption condition of these trees to six kinds of zinc substances and their security. The sealed curative effects of the injected zinc substances which were harmful and could be absorbed steadily by the fruit trees against rosette disease were studied. [ Result] The results of absorption condition and security experiments showed that only zinc-mmnonia complex could be absorbed steadily and safely throughout four seasons. When apple, pear, peach and grape trees affected by rosette disease were injected with zinc- ammonia complex, the leaves of those trees started to grow obviously after 10 d; the internodes of diseased branches elongated, the leaves turned bigger, and the ap- pearance of branches became normal after about 25 d. [ Conclusion] The curative effect of perforated injection of zinc-ammonia complex on fruit tree rosette disease was remarkable. The results also provided a new way for the cure of deficiency diseases of other trace elements.