Fruit Load Research Articles

Effect of number of suckers on date palm source-sink limitation tracked by physiological markers and carbon allocation responsive genes expression

Source–sink balancing is crucial for a fruit load capacity in date palm trees. In date palm trees, coordination of suckers as sink strength with berries as source strength is very significant for economic yield production. The purpose of this study was to use the number of fruit bunches in two fruiting conditions of Off (less than 6 bunches) and On (more than 8 bunches) to identify the source-sink limitation in ‘Mazafati’ date palms with a normal fruit load (6≤bunch number≤8) to determine the optimal number of suckers, as active sinks that compete with berries, to be kept on a date palm. In this study, there were two groups, date palms with 4-5 suckers and date palms with 6-7 suckers. The results showed that the stress caused by 6-7 suckers (as compared to 4-5 suckers) limited source; reduced yield, bunch weight, fruit weight, size, and flavor; and increased fruit shedding and biennial bearing. Date palms with 6-7 suckers and a normal fruit load had a higher content of reducing sugars, a lower content of non-reducing sugars, and less starch in the organelles. They also showed higher trehalose metabolism responsive trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatases (TPP) genes expression along with lower carbon allocation sucrose-phosphate synthase (SPS1), sucrose synthase (SuSy) and invertase (INV) genes expression and enzymes activity in leaflets, which were in line with changes in yield and yield components. Therefore, the optimal number of suckers to be kept on a date palm with a normal fruit load was determined to be 4-5.

Yield and Maturity Estimation of Apples in Orchards Using a 3-step Deep Learning-based Method

Yield and maturity estimation of apples in orchards before harvest is essential for labor resource management. Current yield and maturity estimation are usually manually conducted, which is neither accurate nor efficient. In this paper, a 3-step deep learning–based approach for yield estimation and maturity classification is presented to address these issues. The proposed framework included an optimized detection network to count the visible fruits from both sides of a tree, a classification network to filter out mis-detected objects and perform maturity estimation, and a fruit load estimation algorithm to obtain the total fruit count of a tree. Images from three differ-ent apple orchards were collected to evaluate the performance of the proposed method. According to a series of comparative experiments, the proposed method outperformed several detection networks regarding the counting accuracy, indicating that an optimized architecture of the detection network combined with a fine classification network is necessary for enhanced precision of yield estimation. The presented workflow can be readily extended to other fruit crops for automation yield and maturity estimation featuring high efficiency and accuracy.

Bound to the Land: Cove Fort in Kesler Family History and Memory

Bound to the Land: Cove Fort in Kesler Family History and Memory

The effect of adjusting fruit loading by pruning on the yield and quality of sweet pepper in low light conditions

Pruning and light quality and quantity can affect the fruit load, fruit shape, nutritional value, and quality of sweet pepper. The experiment was arranged as a split-plot conducted in a randomized block design. Treatments consisted of keeping 3, 5, and 7 fruits on the bush, and having un-pruned (P3, P5, and P7 Pnon=without pruning) sweet pepper (Capsicum annuum L., cv. Lumos) with 3 replications. Two greenhouses including 14,000 for the full-light one and 6000-Lux for the low one were designed. The results showed that carotenoid biosynthesis and accumulation were highly related to light, with a significant effect in the full light greenhouse, as compared with the low one. Leaves carbohydrate content was raised in P3 and P5 for both greenhouses and this was more significant in the full light greenhouse, as compared with the low one. TSS was higher in full light with pruning (P3, P5, P7); the highest TSS in the low-light greenhouse was seen in P3. Phenol, antioxidant, vitamin C, and organic acid were higher in the full light greenhouse, as compared with the low one. Conclusively, pruning was more effective on weight after increased growth of bush in the second or third harvest. Longer shape and less flushing are favored by pepper producers. This can be achieved in the full light greenhouse with P3 and then P5 pruning.

Agronomic Performance of Sweet Orange Genotypes under the Brazilian Humid Subtropical Climate

The diversification of Citrus spp. orchards, for both scion and rootstock genotypes, is essential to prevent outbreaks of insects and diseases, improve yield and fruit quality, and extend harvesting and industrial juice processing. Furthermore, this enables growers to obtain higher off-season profits. Citrus plantings were prohibited in most regions of the state of Paraná in the past due to the spread of citrus canker disease. Therefore, this study aimed to evaluate the agronomic performance of distinct early- and mid-season sweet orange cultivars (C. sinensis (L.) Osbeck) regarding vegetative growth, fruit quality, and yield under the Brazilian humid subtropical climate in order to select new alternatives of sweet orange for the industrial and fresh fruit markets. The experimental orchard was planted in 2012 with 15 sweet orange cultivars (early-maturing: Bahia Cabula, Diva, Cadenera, Marrs, Midsweet, Paulista, Rubi, and Westin; mid-season maturing: Berna Peret, Jaffa, Khalily White, Fukuhara, Seleta do Rio, Seleta Tardia, and Shamouti) grafted on Rangpur lime (C. limonia (L.) Osbeck). The experimental design was randomized blocks with three replicates and five trees per plot, analyzed between each maturation group. Data were submitted to analysis of variance followed by Tukey’s test (p ≤ 0.05). Regarding the early-season cultivars, Diva had the tallest trees with largest canopy diameter and volume, differing from Marrs, which had the smallest trees. Shamouti and Khalily White trees were greatly different from all other mid-season cultivars and produced low fruit load over the evaluated period. The early-season Midsweet scored the highest yield and technological index, similar to the mid-season Berna Peret, producing fruits of high juice quality. These genotypes are more effective under the current situation faced by the citrus industry, as the economic life of orchards has been reduced due huanglongbing (HLB). Altogether, Midsweet and Berna Peret genotypes, previously reported as being less susceptible to citrus canker under the same soil–climate condition, are precocious and exhibit higher agronomic potential to be planted in humid subtropical climates, including Brazil and other similar areas around the world.

Effects of fruit load on photosynthetic characteristics of peach leaves and fruit quality

We investigated the effects of fruit load on the photosynthetic characteristics of peach leaves and fruit quality in nine-year-old ‘Xiahui 6’ peach trees. Photosynthetic characteristics, including quantities of photosynthates in leaves of trees with different fruit loads were determined in early May (2 d after fruit set), early June (fruit core-hardening period), early July (10 d before harvest), and late July (2 d after harvest). Quality indicators of mature fruits were determined. The results revealed that leaf photosynthetic rate and chlorophyll content decreased in the first two stages, whereas soluble sugar and sugar alcohol contents increased with a decrease in the fruit load. A contrasting trend was observed in the last two stages. Individual fruit quality, soluble solid content, sugar-to-acid ratio, soluble sugar, and sugar alcohol content increased with a decrease in fruit load. Growth and development were rapid when the fruit load was low, resulting in earlier ripening. Overall, the findings revealed that a 50% fruit load was optimal for the enhancement of yield and fruit quality in mature ‘Xiahui 6’ peach trees under field conditions.

Effectiveness of Aqueous, Alcoholic Extracts and Fertilizing of Jatropha curcas Leaves in the Control of Blossom end Rot of Fruit in Tomato

The blossom end rot of fruit caused by calcium deficiency causes extensive damage going up to more than 50% of yield loss in tomatoes (Solanum lycopersicum L.). The present study was carried out in a greenhouse in a semi-controlled environment to evaluate the effect of aqueous and alcoholic extracts and fertilizing with the powder of the leaves of Jatropha curcas on the growth parameters, the vigor of the plants, the size of the fruit, the rate of blossom end rot fruit, the yield and the accumulation of biomass Cobra 26 and Lindo varieties of tomato. The experimental system was a complete randomized block with 14 treatments repeated 3 times. Control plants were treated with tap water. Estimates of height, annulus diameter, fruit load, fruit size, blossom end rot fruit rate, yield as well as fresh and dry biomass were made. The aqueous extract at a concentration of 2 L/ha had the best vegetative development compared to all the treatments. As for the 3% alcoholic extract, it was the best in reducing the rate of blossom end rot fruits without any loss of yield and in accumulating fresh and dry aerial and root biomass. These results showed that the use of aqueous extracts, alcoholic extracts and the fertilizing with the powder of leaves of Jatropha curcas in the control of the blossom end rot of the tomato makes it possible to reduce efficiently the rate of blossom end rot fruits and the losses of yield.

Impact of genetic and climatic parameters on split-pit incidence in peach and nectarine

Split-pit in peach (Prunus persica L. Batsch) is a physiological disorder occurring during fruit growth causing significant losses to growers, retailers and the canning industry worldwide. In the present study the split-pit susceptibility of 59 recently grown melting-peach and nectarine cultivars was investigated and occurrences were related with phenotypic traits such as ripening date, yield and fruit and stone traits, and climatic parameters such as growing degree hours and rainfall during different periods of fruit growth, in 4 growing seasons. Cultivars with lower propensity to split-pit was separated. The split-pit incidence was higher in nectarine compared with melting-peach, and also in yellow- compared with white-flesh cultivars. Early ripening was the most important parameter related with higher percentage of fruit with split-pit, followed by larger fruit and higher rainfall during 30d after blooming. The fruit and stone dimensions were not related with split-pits, neither was the sum of growing degree hours calculated during different periods after blooming. In conclusion, the present study provides information on the propensity to split-pit disorder of modern melting-peach and nectarine cultivars that may be important information for growers and breeders. A cultivation practice for reducing the split-pit incidence in sensitive cultivars is to aim for smaller fruit sizes, while the spring rainfall experienced could be used by growers as an indication for adjusting fruit load accordingly so that to diminish the expected damages.

The effect of soil type, fruit load and shaded area on ‘Hass’ avocado (Persea americana Mill.) water use and crop coefficients

‘Hass’ avocado tree water use was quantified within orchards located in the three main avocado growing regions of New Zealand, from 2016 to 2019. The three regions, the Bay of Plenty, the Whangarei District and the Aupouri Peninsula in the Far North District, differ in climate and soil type (allophanic, clay, and sandy soils, respectively). At each site, local meteorological conditions were monitored, avocado tree water use was quantified using heat-pulse sap flow measurement, total leaf area was obtained periodically, fruit load was recorded at harvest, and shaded area was measured in mid-summer. Reference evapotranspiration (ETo) calculated by the FAO-56 Penman-Montieth equation was highest in January at 3.8 mm (Whangarei) to 4.3 mm (Bay of Plenty) and lowest in June at 0.7 mm (Bay of Plenty) to 0.8 mm (Whangarei and Far North). The three sites had similar patterns of tree water use relative to ETo, regardless of the differences in soil type, and tree water use was highest in January at 2.7 mm d−1 and lowest in June at 1.2–1.4 mm d−1. Across the three sites, individual tree water use was related to variation in tree spacing and leaf area per tree, but on an orchard area basis was influenced more by fruit load, resulting in variation in estimated crop coefficients (Kc) among individual trees and seasons at all sites. Average monthly Kc was similar across all sites with a value of 0.60–0.65 in mid-summer, as all three orchards were considered mature with fully grown canopies and > 75% orchard shaded area. However, tree water use also increased from light to heavy fruit load. Therefore, when irrigation is applied to avocado, Kc values should be adjusted for variation in fruit load, with a range from 0.50 to 0.85 in mid-summer.

Identification of potential regulators of cell production and early fruit growth in apple (Malus × domestica Borkh.)

Fruit size is a commercially valuable trait that is determined by the extent of fruit growth. In apple, (Malus × domestica Borkh.), early fruit growth is facilitated by intensive cell production, but mechanisms regulating these processes are not well understood. In this study, members of five gene families involved in growth regulation were identified and evaluated in apple: AUXIN-REGULATED GENE INVOLVED IN ORGAN SIZE (ARGOS); CELL NUMBER REGULATOR (CNR); GROWTH REGULATING FACTOR (GRF); GRF INTERACTING FACTOR (GIF); and KLUH. MdARGOS1 and MdARGOS2 transcript abundance was higher during early fruit growth but was also enhanced by up to 18-fold under conditions of reduced cell production during flower and fruit development, indicating that their gene products play complex roles in regulating growth mechanisms during early development. MdCNR20a and MdCNR20b transcript abundance decreased during early fruit growth and increased during the transition from cell production to cell expansion. MdCNR20a transcript abundance was negatively correlated with the relative cell production rate (RCPR; ρ = - 0.82; P = 0.002), was enhanced in response to shading, and reduced in response to lower fruit load, indicating that it's gene product negatively regulates cell production and early fruit growth. Transcript abundance of MdGRF11 and MdGRF16 was greater during cell production-mediated fruit growth, and higher in the cortex than in the pith. MdGIF3 transcript abundance was greater during early fruit development, higher in the cortex, enhanced under reduced fruit load conditions, and strongly correlated with RCPR (ρ = 0.93; P < 0.0001). Further, it was correlated with that of MdGRF11 and MdGRF16 (ρ = 0.87 and 0.89, respectively; P < 0.0001), indicating that the GRF11/16-GIF3 module is co-regulated and involved in spatio-temporal regulation of cell production and fruit growth. Transcript abundance of MdKLUH1 was low and not consistent with a role in regulating cell production and fruit growth. Together, this study demonstrates coordinated control of cell production during early fruit growth by multiple regulatory components, identifies candidates for functional characterization, and provides potential tools for enhancing growth of the apple fruit.

Thinning in peach: Past, present and future of an indispensable practice

Peach (Prunus persica L. Batsch) trees need to be thinned in order to guarantee yield of fruits of marketable size and a sufficient return to bloom in the following season. In this fruit crop, however, thinning is often complicated by several endogenous as well as exogenous factors, such as genotype, orchard structure, environmental conditions and agronomic management, and the current thinning methods (manual, mechanical or chemical), taken singularly, present more disadvantages than advantages. Therefore, the only possible option is currently represented by the adoption of a “thinning strategy”, consisting in subsequent interventions at different phenological stages, to finely tune the final fruit load along its physiological evolution. Such strategies must also consider the ongoing climate changes, which further complicates the thinning interventions also due to the lack of Decision Support Systems (DSSs), and the current trends of the global market. The present review takes a picture of the current situation of peach thinning, with a particular focus on the current development of new chemical thinners, and its future perspectives. Some general remarks are made considering the evolution of the global market and the obstacles found in peach research in some of the most traditional peach areas of the world.

Improved forecasting of coffee leaf rust by qualitative modeling: Design and expert validation of the ExpeRoya model

CONTEXTCoffee leaf rust (CLR) epidemics on Coffea arabica have led to severe socio-economic crises in Latin America starting in 2008. Until now, the scattered nature of scientific and empirical knowledge of the highly complex CLR-coffee pathosystem has been an obstacle to the development of CLR forecasting models. OBJECTIVETo help prevent new severe epidemics, we built ExpeRoya, a qualitative model, based on a review of the scientific literature and expert opinion, to forecast the risk of a monthly increase in the incidence of CLR at plot and landscape levels. METHODSWe adopted the IPSIM (Injury Profile SIMulator) framework, a qualitative and aggregative modeling approach that describes the effects of the cropping system and the plot environment on injuries, thereby making it possible to incorporate scattered knowledge on the system and all its complexity in a simplified way. Involving experts makes this approach powerful and robust because it builds on empirical knowledge based on a very large number of field observations. We argue that broad expert knowledge provides more accurate information on the manifold interactions in the system than existing quantitative models can. The structure of ExpeRoya was discussed with coffee sector experts in 19 workshops and validated in an online survey with 17 CLR experts. RESULTS AND CONCLUSIONSExpeRoya successfully integrates in a simple way 229 multiple interactions that exist within the CLR-coffee pathosystem based on only 12 input variables easily acquired in the field: one incidence monitoring variable; two meteorological variables (temperature and rainfall), four crop management variables (management of shade cover, fungicide application, nutrition and pruning of coffee trees) and five coffee tree characteristics (dates of flowering, beginning and end of harvest, fruit load and cultivar genetic resistance). Coffee institutes in Honduras and Nicaragua now use ExpeRoya, hosted by the platform Pergamino (https://www.redpergamino.net/app-experoya), to assist them in preparing their monthly CLR warning bulletins for growers. ExpeRoya is an improved forecasting model of CLR by fully incorporating the main biophysical factors affecting CLR at the plot and landscape levels. SIGNIFICANCEExpeRoya is both a framework and a proof of concept that improves both forecasting and the comprehensive modeling of CLR. ExpeRoya is a powerful yet user-friendly model designed for all actors of the coffee sector, particularly smallholder farmers and extension agents. ExpeRoya is adaptable: users can modify the model according to advances in knowledge and/or their own expertise of the system. ExpeRoya can help prevent future socio-economic crises.

Impact of Training System and Fruit Load on Seed Yield, Quality and Economics of Seed Production in Bell Pepper (Capsicum Annuum L)

Impact of Training System and Fruit Load on Seed Yield, Quality and Economics of Seed Production in Bell Pepper (Capsicum Annuum L)

Estimation of Optimal Support Position for Fruit Tree Based on Finite Element Method Considering Branch Formation

In fruit cultivation, hanging branch is effective to prevent branch breakages. The hanging position is usually determined based on the farmer's experiences in the viewpoints of fruit growing and harvesting. It is important to identify the optimal hanging position considering with the mechanical stress distribution to effectively prevent the breakage. In this study, the optimal hanging position of tree branches was estimated by using finite element analysis. A branch model with the taper shape as the same of actual branch shape was loaded to an equally distributed load considering the fruit loads, and the maximum principal stress generated in the model with bending deformation was used to evaluate the hanging effect. The analyses were performed under various conditions by changing the inclination angle of branch and the taper ratio of the branch. The results showed that the optimal hanging positions were slightly shifted from the center to the apical sides of branch in the cases of the branch extended transversely with a certain degree of inclined angle. And it was found that the incorrect hanging positions led to decrease the stress reduction effects.

Water Management for Pomegranate Orchards

Pomegranate has been an export-oriented crop for the last one or two decades and its area and production is growing rapidly in India. Domestic production and export demand are the driving forces behind the country's cultivation. India ranks first in the world in pomegranate production and Maharashtra is leading in pomegranate production in the country. Pomegranate production in Maharashtra is water deficient and hence water management is very important for pomegranate orchards to achieve targeted productivity. Therefore crops need to be irrigated as required. The water requirement of pomegranate orchards depends on the age of the plant, fruit load, season and soil type. In this study, we have given average monthly irrigation water requirement for pomegranate orchards in Maharashtra according to the age of the orchards. Also we have given the average irrigation water requirement in Ambe, Mrig and Hasta bahars of pomegranate orchards according to their age, season and growth stages.

Estimation of Photosynthesis and Fruit Load of Strawberry

Estimation of Photosynthesis and Fruit Load of Strawberry

Potassium dynamics in orchard soil and potassium status of sour cherry trees affected by soil nutritional conditions

The influence of mineral fertilizers on the seasonal dynamics of exchangeable potassium in the soil, potash status and productivity of trees was studied in field experiment with sour cherry trees cv. ‘Turgenevka’ in soil-climatic condition of Central Russian upland in 2018-2019. The urea and potassium sulfate were applied annually in early spring at doses of N30K40, N60K80, N90K120, and N120K160 kg/ha. The potassium level in soil-plant system depended on weather conditions, the doses of fertilizers and uptake of the element by trees. The reserves of exchangeable potassium in loamy Haplic Luvisol at the level of 100-200 mg/kg were sufficient to ensure the sour cherry yield in the start of fruiting. Fertilization by doses of N60K80 and higher increased the content of exchangeable potassium in root zone (more than 200 mg/kg), but the features of potassium seasonal dynamics were similar to unfertilized plots. With increase in the average fruit load from 4.6 (2018) to 8.3 (2019) kg/tree, the uptake of potassium by young trees increased, which led to a significant decrease in the concentration of potassium in the soil and leaves during the fruit development period (June and July). Fertilization reduced this effect but did not significantly influence on the productivity of trees and fruit potassium status.

Prediction of upland cotton micronaire accounting for the effects of environment and crop demand from fruit growth

AbstractEnvironment and crop management can play an important role in determining upland cotton (Gossypium hirsutum L.) fiber quality. An important quality parameter is fiber micronaire, which is an indirect measure of fiber linear density (fineness) and maturity, and it is affected by crop supply and partitioning of assimilates to cotton fruit. High micronaire occurs when there is an excess of assimilates because of good growing conditions and fruit number is low. Conversely low micronaire occurs when growing conditions are poor and fruit number is high. Little research has established the degree of impact of these variables in combination influencing micronaire. Two field experiments were conducted to generate variability in micronaire by changing planting time, cultivars, canopy size, and fruit load (boll number). From these experiments, a significant relationship (r2 = 0.79) to predict micronaire was generated using temperature during crop fiber filling, leaf area index (LAI) at the start of crop fiber thickening, and the mass of individual bolls at harvest. Subsequent experiments in different seasons (included variations in planting time, fruit load, and water deficit during fiber thickening) successfully validated the relationship. Reasonable success was attained in predicting fiber linear density and maturity ratio independently and then used to calculate estimates of micronaire. Prediction of these quality attributes may offer more detailed information on the effects of environment and management influencing fiber quality affecting yarn quality. Overall, the ability to predict micronaire (and potentially its components) could be used to refine management decisions to improve fiber quality management prior to or at harvest time.

Apple stem/calyx real-time recognition using YOLO-v5 algorithm for fruit automatic loading system

Fruit loading and packaging are still labor-intensive tasks during postharvest commercialization, of which the key issues is to realize the real-time detection and adjustment of fruit posture. However, fruit stem/calyx position is a key structural characteristic for fruit posture and will also affect fruit internal quality detection. In this paper, an image acquisition system based on fruit posture adjustment equipment was set up, and the YOLO-v5 algorithm based on deep learning was used to study the real-time recognition of stem/calyx of apples. First, hyperparameters were determined, and the training method of transfer learning was used to obtain better detection performance; then the networks with different widths and depths were trained to find the best baseline detection net; finally, the YOLO-v5 algorithm was optimized for this task by using detection head searching, layer pruning and channel pruning. The results showed that under the same setting conditions, YOLO-v5s had a more superior usability and could be selected as the baseline network considering detection performance, model weight size, and detection speed. After optimization, the complexity of the algorithm was further reduced. The model parameters and weight volume were decreased by about 71 %, while mean Average Precision (mAP) and F1-score (F1) were only decreased by 1.57 % and 2.52 %, respectively. The optimized algorithm could achieve real-time detection under CPU condition at a speed of 25.51 frames per second (FPS). In comparison with other deep learning target detection algorithms, the algorithm used in this paper was similar to other lightweight networks in complexity. Its mAP and F1 were 0.880 and 0.851, respectively. This was better than other one-stage object detection algorithms in detection ability, only lower than that of Faster R-CNN. The optimized YOLO-v5s achieved 93.89 % accuracy in fruit stem/calyx detection for different cultivars of apples. This research could lay the foundation for the automation of fruit loading and packing systems.

Metamitron, a Photosynthetic Electron Transport Chain Inhibitor, Modulates the Photoprotective Mechanism of Apple Trees.

Chemical thinning of apple fruitlets is an important practice as it reduces the natural fruit load and, therefore, increases the size of the final fruit for commercial markets. In apples, one chemical thinner used is Metamitron, which is sold as the commercial product Brevis® (Adama, Ashdod, Israel). This thinner inhibits the electron transfer between Photosystem II and Quinone-b within light reactions of photosynthesis. In this study, we investigated the responses of two apple cultivars—Golden Delicious and Top Red—and photosynthetic light reactions after administration of Brevis®. The analysis revealed that the presence of the inhibitor affects both cultivars’ energetic status. The kinetics of the photoprotective mechanism’s sub-processes are attenuated in both cultivars, but this seems more severe in the Top Red cultivar. State transitions of the antenna and Photosystem II repair cycle are decreased substantially when the Metamitron concentration is above 0.6% in the Top Red cultivar but not in the Golden Delicious cultivar. These attenuations result from a biased absorbed energy distribution between photochemistry and photoprotection pathways in the two cultivars. We suggest that Metamitron inadvertently interacts with photoprotective mechanism-related enzymes in chloroplasts of apple tree leaves. Specifically, we hypothesize that it may interact with the kinases responsible for the induction of state transitions and the Photosystem II repair cycle.