Effects of blooming and fruit thinning on the yield, fruit quality, and leaf photosynthesis of peach cultivar ‘Xiahui 5’ in China (2024)

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Abstract

Introduction

Achieving high yields of high-quality fruit from fruit trees primarily relies on regulating the number of fruit through thinning (Chanana et al., 1998; Koike et al., 2003; Iwanami et al., 2018; Kumarihami et al., 2021). Thinning helps balance the relationship between reproduction and growth, prevents excessive fruit set, improves fruit quality, reduces nutrient consumption, and enhances tree stress resistance and flower bud quality (Covarrubias et al., 2021). Thinning practices vary depending on flowering characteristics, tree varieties, and geographical climates (Jiménez and Díaz, 2002). For example, varieties with small flower loads require fewer flowers to be thinned, with fruit thinning being used to adjust the load. In northern China, fruit thinning is commonly used for deciduous fruit trees owing to spring cold snaps. Extreme weather in spring is rare in the middle and lower reaches of the Yangtze River, as well as in the southern production areas of China; therefore, blossom and fruit thinning can be carried out in stages.

Fruit thinning changes the source–sink balance and allocates more carbon from the leaves to the fruit. Fruit thinning can cause the instantaneous accumulation of soluble sugars in peach leaves, weakened photosynthesis, and stomatal closure (Volpe et al., 2008; Andrade et al., 2019). Blossom thinning and fruit thinning may be performed manually, mechanically, or chemically (Martin-Gorriz et al., 2012; Sarkadi, 2012; Deshmukh et al., 2017). Thinning can be applied during flowering or post-bloom. Blossom thinning reduces both fruit set and yield (Greene et al., 2001; Drogoudi et al., 2009). However, the optimum time to thin is considered to be 21–28 d after full bloom (DAFB; Grossman and DeJong, 1995; Njoroge and Reighard, 2008). Therefore, both blossom thinning and fruit thinning are effective measures to ensure peach fruit set and yield. The simultaneous application of these two thinning methods may be beneficial for reducing labour input for fruit thinning. Sutton et al. (2020) optimized a blossom- and fruit-thinning strategy in the south-eastern peach production area of the USA and reported that thinning flowers during the flowering period or thinning fruit 21 DAFB increases the single fruit weight of two varieties, ‘Cary Mac’ and ‘July Prince’. However, thinning flowers during the flowering period may lead to a decrease in yield, and increasing the number of fruit per plant often leads to a decrease in single-fruit weight. Combining blossom- and fruit-thinning strategies in the early stage of fruit development can achieve a fixed number of fruit per peach tree. Deshmukh et al. (2017) found that fruit thinning and fruit spacing significantly impact the overall fruit quality of peaches.

The objective of this study was to investigate how peach yield, fruit quality, and leaf photosynthetic characteristics of the main peach cultivar ‘Xiahui 5’ in the middle and lower reaches of the Yangtze River of China are affected by different blossom- and fruit-thinning methods. We also compared the labour input required to provide a scientific reference for ensuring high and stable yields while improving fruit quality.

Materials and Methods

Experimental site

The experiment was conducted at the Peach Experimental Orchard of Jiangsu Academy of Agricultural Sciences, located in Nanjing City, Jiangsu Province, China (32°2ʹ N, 118°52ʹ E, 11 m above sea level). The climate of this region is subtropical monsoon climate, with an average annual temperature of 15.7°C, an annual accumulated temperature of approximately 4800°C, and a frost-free period of 220–240 d. The soil is clay loam, with pH of 6.8, an organic matter content of 23.34g/kg, and available nitrogen, phosphorus, and potassium contents of 136.94, 47.89, and 65.44mg/kg, respectively.

Materials

The experimental materials were ‘Xiahui 5’ peach (Prunus persica (L.) Batsch) trees with full productive age grafted onto ‘Maotao’ and having similar vigour. The tree shape was a natural open-centre form with three main branches, and trees were shaped using the long-shoot pruning method. During summer pruning, the focus was on removing the bore branches. The planting density was 3 m between trees and 5 m between rows, with a north–south row direction and ridge cultivation mode. The ridge height was 0.4 m. Conventional cultivation measures were used for disease and pest control and for soil, fertilizer, and water management. According to the occurrence of diseases and insect pests, measures were taken to prevent and control them in a timely manner. Irrigation was appropriate when drought persisted, and irrigation was controlled in the rainy season or in rainy weather using spray irrigation system. Water balance was maintained during the late stage of fruit development. Irrigation was conducted immediately after surface and underground fertilization. Irrigation was controlled within 10 d before harvest. Daily mean temperature and precipitation from the full-blossom stage to the harvest stage of ‘Xiahui 5’ peach are presented in Figure 1, which indicates that it was necessary to take defensive measures before harvest. In this study, the ripening stage of ‘Xiahui 5’ peach was during the rainy season in the middle and lower reaches of the Yangtze River in China. To prevent the influence of precipitation on fruit quality, a 2-m wide waterproof mulch was laid under both sides of each tree following the direction of the tree 1 week before fruit harvesting. During the core-hardening period of fruit (mid-June), phosphorus- and potassium-containing fertilizer was applied to promote fruit expansion. Basal fertilizer (45 t/ha of sheep dung) was applied in September after the growth of new shoots stopped.

Strategies

The experiment was conducted for two years (2011 and 2012). In the first year, we performed experimental preparatory actions to observe and investigate the experimental effects on fruit growth and development, yield and fruit quality, whereas in the second year, the formal experiment was performed for one year. The full-bloom period of ‘Xiahui 5’ peach was early April. The following four blossom- and fruit-thinning treatments were established: blossom thinning+fruit thinning at 20 DAFB+fruit thinning at 40 DAFB (T1); blossom thinning+fruit thinning at 40 DAFB (T2); fruit thinning at 20 DAFB+fruit thinning at40 DAFB (T3); and fruit thinning at 40 DAFB (T4). Neither blossom nor fruit thinning was performed in the control group (control). For each treatment, there were 2 trees per plot, and the experiment was repeated three times. The number of flowers per tree was counted before flowering, and blossom thinning was performed after 50% of the flowers on the whole tree had bloomed (April 2), with flowers on the top and basal parts of the one-year shoots (approximately one-third of the flowers) being thinned. Fruit thinning for the first time was performed at 20 DAFB (T1 and T3), and malformed, diseased, and small fruit, as well as those growing in clusters, facing upwards, or without leaves, were thinned. Fruit in the middle of branches that had no less than 3 fruit on the same branch and whose distance between adjacent fruit was obviously less than 20cm were thinned. At the end of this fruit-thinning operation (20 DAFB), approximately half of the fruit on the whole tree was thinned. Except for the control, the fruit load of each treatment was determined according to the trunk cross-sectional area (TCSA) of each tree at the end of the experiment (40 DAFB). Additionally, the degree of thinning was spaces of approximately 20cm between fruit (longer bearing branches). The final rate of fruit set for the test trees was maintained at approximately 15%–25%.

At 40 DAFB, fruit samples were collected from each treatment, with mature fruit samples being collected when the fruit skin colour changed from green to milky white (July 5). Ten fruit samples were randomly collected from each tree in each direction (east, west, south, and north) and quickly transported to the laboratory within 10min. Twenty fruit samples were randomly selected from each treatment for analysis and relevant determinations, which were performed with three replicates. The time (expressed in hours, h) taken by each tree in each treatment for blossom thinning and fruit thinning wasrecorded, and the time spent by each treatment (labour usage) per hectare (ha) of peach trees for blossom thinning and fruit thinning was converted based on the plant spacing and row spacing (3 m×5 m). The weight of all fruit per tree was recorded at the fruit ripening stage, and the yield per ha was calculated based on the plant spacing.

The longitudinal, transverse, and lateral diameters of the fruit were measured using a Vernier caliper (Beaverton, OR, USA). The single fruit weight was determined using an electronic balance with a sensitivity of 0.01g. The soluble solids content (SSC) of the fruit flesh was measured using a PAL-1 refractometer (ATAGO, Itabashiku, Japan) at 20°C, with the measurement location being the middle of the fruit on both sides of the fruit suture. The firmness with skin and thefirmness without skin were measured using a TA.XT Plus Texture Analyser (Stable Micro-Systems Texture Technologies Co., Scarsdale, NY, USA) with a probe diameter of 8mm, a penetration speed of 1mm/s, and a test depth of 5mm. The measurement location was the middle of the fruit on both sides of the fruit suture (Zhang et al., 2017).

The brightness value (L*), red saturation (a*), and yellow saturation (b*) of the fruit skin were measured using a ColorQuest XE colour difference meter (Hunter Lab, Reston, VA, USA) using the Hunter Lab colour system, and the colour saturation (C) and hue angle (h) were calculated. The determinations of soluble sugars, sugar alcohols, and organic acid contents followed the methods of Zhang et al. (2015). The fruit skin was removed using a peeler, and the fruit flesh was cut, minced, and mixed after weighing the sample. An Agilent 1260 high-performance liquid chromatography system was used(Agilent Technologies,Santa Clara, CA, USA), and the measured indicators were the contents of soluble sugars (sucrose, glucose, and fructose), sugar alcohol (sorbitol), and organic acids (malic, quinic, and citric). The main sugar content was the sum of the contents of soluble sugars and sugar alcohol, and the main organic acid content was the sum of the contents of malic, quinic, and citric acids. The ratio of the main sugar content to the main acid content was recorded as the sugar toacid ratio. At the core-hardening and ripening stages of the fruit, on a sunny and windless day from 9:00 to 10:00, the photosynthetic parameters, including the light quantum flux density (PFD), net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO₂ concentration (Ci), were measured using a Li-6400 portable photosynthesis measurement system (LI-COR, Lincoln, NE, USA). Six replicates were performed, and the average values were calculated. The water-use efficiency (WUE), apparent light-use efficiency (LUE_app), and apparent CO₂-use efficiency (CUE_app) were calculated, where WUE=Pn/Tr (Nijs et al., 1997), LUE_app=Pn/PFD (Long et al., 1993), and CUE_app=Pn/Ci (Marler et al., 1993; He and Ma, 2000).

Data analysis

Data processing and mapping were performed using Excel software, and the significant difference analysis was conducted using SPSS software (IBM, Armonk, NY, USA). A completely randomized block experiment was designed. Different treatments were compared using Duncan’s new multiple range test after analysis of variance (ANOVA). Mean separation at P<0.05 was considered significant.

Results

Differences in fruit size during the young fruit period under different blossom- and fruit-thinning methods

As shown in Table 1, differences in fruit size among the various treatments of ‘Xiahui 5’ peaches began to appear when fruit thinning was performed at40 DAFB. Because T4 only underwent fruit thinning at 40 DAFB, there were no significant differences in longitudinal, transverse, lateral diameter, or single-fruit weight compared with those of thecontrol. There were no significant differences in the longitudinal diameter of the fruit among T1, T2, and T3, but they were all significantly longer than those of thecontrol. The transverse and lateral diameters of T3 were significantly longer than those of thecontrol, whereas those of T1 and T2 were not significantly different from those of thecontrol. The single-fruit weights of T1, T2, and T3 were significantly greater than that of control, with the following size ranking: T3>T1>T2>control (P<0.05). This indicates that thinning fruit once during the young fruit period better promoted fruit enlargement than thinning flowers once or thinning flowers and fruit once each, and the most effective thinning operation affecting peach fruit size was performed at 20 DAFB.

Differences in sugar and acid contents of fruit during the young fruit period under different blossom- and fruit-thinning methods

Table 2 shows the differences in soluble sugar, sugar alcohol, and organic acids contents of ‘Xiahui 5’ peaches resulting from fruit thinning and fruit setting at 40 DAFB under different treatments. However, there were no significant differences in sucrose, glucose, fructose, sorbitol, malic acid, quinic acid, or citric acid contents of T4 fruit compared with those of thecontrol. The sucrose contents of T1, T2, and T3 fruit were significantly higher than that of thecontrol, with T1 having the highest level. The differences in glucose and fructose contents among the different treatments were similar. The contents of T3 were significantly higher than those of the control, those of T2 were not significantly different from those of control, and the contents of T1 were significantly lower than those of the control. The sorbitol content was significantly higher in T3 than in the control, whereas it was relatively lower in T1 and T2. The malic acid contents of T1, T2, and T3 fruit were significantly lower than that of thecontrol, with T2 having the lowest level. The quinic acid contents of T1 and T3 were significantly higher than that of the control, whereas that of T2 was significantly lower. The citric acid content was not significantly different between T3 and thecontrol, but those of T1 and T2 were similar and significantly lower than that of the control. This indicated that different combinations of blossom- and fruit-thinning techniques may have significant impacts on the accumulation of soluble sugars, sugar alcohol, and organic acids in young peach fruit, which may cause differences in the corresponding component contents in mature fruit.

Effects of blossom- and fruit-thinning on peach fruit size and yield

As shown in Table 3, Figure 2, and Figure 3, different blossom- and fruit-thinning methods significantly affected the size of ‘Xiahui 5’ peach fruit. The longitudinal diameters of all the treatment groups were significantly greater than that of thecontrol, with T1 having the longest diameter, followed by T3. The transverse and lateral diameters of all the treatment groups were significantly longer than thoseof the control, with those of T1 and T3 being longer and similar in length, whereas those of T2 and T4 were shorter and similar in length. The single-fruit weights and yields of different treatments were significantly higher than those of thecontrol, with the ranking being T3>T1>T2, T4>control (P<0.05). In terms of fruit crop load (fruit per cm² TCSA) per treatment, all theblossom- and fruit-thinning treatments had significantly lower values than that of the control. This indicated that blossom- and fruit-thinning can increase the fruit size of peach fruit and improve yield, and thinning fruit twice during the young fruit period had the greatest effect.

Effects of blossom- and fruit-thinning on peach fruit flavour

Differences in SSC and sugartoacid ratio of ‘Xiahui 5’ peach fruit under different blossom- and fruit-thinning treatments are shown in Figure 4. The SSC of different blossom- and fruit-thinning treatments was significantly higher than the control, with T1 and T3 being the highest, followed by T2 and T4. For the sugartoacid ratio, all blossom- and fruit-thinning treatments were significantly higher than thecontrol, with T3 being the highest. Thinning fruit twice (T1 and T3) increased the contents of fruit components, and T3 had the highest sugartoacid ratio, indicating that the fruit flavour would be desirable when the fruit was thinned twice.

Effects of blossom- and fruit-thinning on peach fruit firmness

The firmness of ‘Xiahui 5’ peach fruit was affected by blossom- and fruit-thinning methods (Figure 5). The fruit firmness levels with and without skin for all the treatments were significantly lower than those of thecontrol, with T1, T2, and T3 being lower than that of T4, and they were not significantly different from each other. The lack of thinning blossoms or fruit resulted in high fruit firmness levels, which significantly affects normal fruit maturation; the fruit firmness after thinning once is greater than that of fruit from trees subjected to more than two blossom- and fruit-thinning procedures.

Effects of blossom- and fruit-thinning on peach fruit colour

The effects of blossom and fruit thinning on the colour of ‘Xiahui 5’ peach fruit were significant (Table 4). For L*, a*, and a/b, all the treatment groups had significantly greater values than those of the control, with T1 and T3 having the highest values, followed by those of T2 and T4. The b* values of T2 and T4 were not significantly different from that of the control, whereas those of T1 and T3 were significantly lower than that of the control. The C values of all the treatment groups were similar but significantly higher than that of the control. The h values of all the treatment groups were significantly lower than that of the control, with those of T1 and T3 being the lowest. This indicates that blossom- and fruit-thinning can significantly improve the appearance quality of peach fruit. Regardless of whether blossoms were thinned or not, fruit thinned twice during the young fruit period had a more obvious red colour.

Effects of blossom- and fruit-thinning on sugar and acid contentsof peach fruit

As shown in Table 5, the sucrose contents of all blossom- and fruit-thinning treatments were significantly higher than that of the control, with those of T1 and T3 being the highest. The glucose contents were highest in T2 and T3, followed by T1, T4, and thecontrol. The fruit glucose contents of all the treatment groups were significantly lower than that of the control, with those of T1 and T4 being the lowest and those of T2 and T3 being in the middle. The sorbitol contents of all the treatment groups were significantly lower than that of the control, with those of T1, T3, and T4 being the lowest. The malic acid contents of all the treatment groups were significantly lower than that of the control, with that of T3 being the lowest. The quinic acid contents of all the treatment groups were significantly higher than that of the control, with that of T1 being the highest. The citric acid contents were not significantly different between T2 and the control, but the contents of all the other treatments were lower than that of the control, with that of T3 being the lowest. This indicated that different blossom- and fruit-thinning methods can affect the composition of sugars and acids in peach fruit, which can change the flavour of the fruit.

Effects of blossom- and fruit-thinning on photosynthesis of peach fruit

As shown in Table 6, the Pn and Gs values of different blossom- and fruit-thinning treatments during the core-hardening and mature stages of fruit were significantly lower than those of the control, with those of T1 and T3 being the lowest and not significantly different from each other. The WUE in both the core-hardening and mature periods of T1 and T3 were significantly higher than that of the control, with that of T3 being the highest. The WUE values of T2 and T4 were not significantly different from that of the control during the mature period but weresignificantly lower than that of thecontrol during the core-hardening period. The LUE_app valuesof T1 and T3 during the core-hardening and mature stages were not significantly different from that of the control, whereas those of T2 and T4 were significantly lower than that of the control. The CUE_app values of T2 and T4 were similar to that of the control, whereas those of T1 and T3 were relatively higher than that of control during the core-hardening period. During the mature period, the CUE_app of T3 was the highest, followed by that of T1, with those of T2 and T4 being the lowest and not significantly different from that of the control. This indicates that blossom- and fruit-thinning can reduce the carbon assimilation capacity of peach leaves and reduce the opening degree of stomata. However, thinning fruit twice (T1 and T3) can improve the WUE and CUE_app values of leaves, accelerate the activity of mesophyll cells, and improve the efficiency of CO₂ assimilation.

Labour usage under different blossom- and fruit-thinning methods

As shown in Figure 6, for ‘Xiahui 5’ peach tree blossom and fruit thinning, the labour usage per ha was highest for T1 and lowest for T4 (P<0.05). The labour usages for T2 and T3 were not significantly different and were at an intermediate level, which was significantly different from the levels for T1 and T4. Thus, the more field operations performed to adjust the peach tree load through blossom and fruit thinning, the greater the labour usage.

Discussion

Many peach orchards are usually hand-thinned during the blooming period or approximately 20–60 d after bloom, and these operations are often applied in peach orchards with relatively small area. Manual thinning of flowers and fruit is less affected by environmental conditions, which can accurately control fruit weight and yield. However, this practice is labour-intensive and costly (Torres et al., 2021). The use of chemical thinning methods (ethephon, NAA, etc.) to reduce flowers and fruit can save labour usage and improve labour efficiency. However, this method is greatly affected by external environmental conditions, and the application concentration on different peach varieties needs to be investigated through long-term experimental research (Sharma et al., 2003; Torres et al., 2021). Therefore, chemical thinning of flowers and fruit is more suitable for the application of peach orchard with relatively large area.

Torres et al. (2021) reported that bloom-thinning has a distinct advantage over fruit-thinning because it can be done early during fruit development. Therefore, competition between developing fruitlets can be reduced at the earliest stage. On the basis of evaluating the effect of peach blossom- and fruit-thinning, combined with the period of fruit-thinning, this studycarried out several combination treatments, which were of great significance to further clarify the period and frequency of peach blossom- and fruit-thinning.

Fruit is the primary storage organs of fruit trees. Their growth and development depend on the photosynthetic assimilation products accumulated by leaves (Walcroft et al., 2004). Thinning blossoms and fruit can change the leaf to fruit ratio, leading to changes in assimilation product accumulation and distribution in leaves, as well as changes in the balance between nutritional and reproductive growth (Berman and DeJong, 1996; Myers et al., 2002). The balanced regulation of fruit trees between vegetative growth and reproduction is mainly realized by blossom- and fruit-thinning. Moderate thinning during the blossoming period can increase the weights of individual fruit without reducing yield (Wu et al., 2005; Coneva and Cline, 2006; de Oliveira et al., 2017), but excessive thinning can reduce yields and affect economic benefits (Greene et al., 2001; Deshmukh et al., 2017). Thus, combining blossom- and early fruit-thinning may be more effective to meet desired goals (Sutton et al., 2020).

In this study, the weights of individual fruit and yields of ‘Xiahui 5’ peach trees that underwent blossom- and fruit-thinning treatments were higher than those without thinning (P<0.05). The weights of individual fruit, mature fruit weights, and yields of blossom- and fruit-thinning treatments (T1 and T4) were lower than those of T3, which may be because ‘Xiahui 5’ peach trees have a relatively weak ability to accumulate photosynthetic assimilation products from newly grown leaves to mature functional leaves. Thinning blossoms reduces the ‘storage strength’ but also reduces the accumulation of photosynthetic assimilation products in the fruit, affecting the growthof young fruit. Here, the T3 plants had the highest single fruit weight and yield. The fruit size data of each treatment during the young fruit period (Table 1) suggested that at 20 DAFB, the young fruit of ‘Xiahui 5’ peach is in a period of rapid expansion. After removing half of the fruit on the entire tree at once, the tree is stimulated. The remaining fruit quickly expanded after receiving assimilates from the leaves, resulting in a higher accumulation of assimilates than in theother treatments. In addition, T3 had the most desirable fruit colour, which may be because the increased light exposure after large-scale fruit thinning promotedthe accumulation of substrates of anthocyanins by reducing the adverse effects of carbon allocation on leaves, thereby improving fruit colour (Sansavini and Corelli-Grappadelli, 1997; Costa and Vizzotto, 2000). Additionally, the single-fruit weight and yield of ‘Xiahui 5’ plant after thinning at 40 DAFB (T4) were the lowest among all the treatments. This was likely attributed to the fruit having entered the first source limitation period of growth and development, as well as the timing of thinning being relatively late (Grossman and DeJong, 1995; Njoroge and Reighard, 2008).

Understanding the effects of the experiment on the quality of the harvested fruit was the main goal (Corelli-Grappadelli and Coston, 1991; Barreto et al., 2019; Tao et al., 2023; Zhang et al., 2023). Deshmukh et al. (2017) found that when the distance between the fruit is 15–20cm and thefruit is thinned at 20 DAFB, the ‘Flordasun’ peach has more desirable fruit colouring and has the highest solidtoacid ratio, soluble solids, and main sugar contents. Additionally, the fruit have the lowest titratable acid content. They also revealed that fruit thinning at 20 DAFB has a positive impact on the overall quality of peach. Similarly, our study found that both the T1 and T3 treatment groups, which underwent fruit thinning at 20 DAFB, had the highest SSC values. Additionally, theT3 fruit had the highest sugartoacid ratio, whereas the fruit firmness was lower than that of thecontrol. However, the maturity of thecontrol fruit was affected by the lack of blossom- and fruit-thinning operations, which resulted in increased ripening difficulty and higher hardness values than the other treatments. The higher fruit firmness of thecontrol fruit might be due to smaller fruit size and slower growth rate, which in turn increases the strength of the cell wall and lessens cohesion between the cells (Drogoudi et al., 2009; Deshmukh et al., 2017). In this study, the indexes of single-fruit weight, yield, SSC, sugartoacid ratio, L*, a*, and a/b reached high levels, whereas the main organic acid content was the lowest compared with that of theother treatments when the fruit was thinned at both 20 DAFB and 40 DAFB (T3). Thus, the fruit produced by T3 had a more desirable overall quality.

Changes in leaf photosynthetic characteristics areclosely related to fruit quality. The Pn of the leaves decreased due to thinning. However, the leaves of T3 during the core-hardening stage and those of T1 and T3 during the mature stage had relatively higher WUE values. This is because fractional fruit thinning can alleviate the water deficit of leaves and reduce the water transpiration rate and leaf stomatal conductance, thereby increasing the WUE (McFadyen et al., 1996; Bustan et al., 2016). This study also found that the sucrose content of all treatments was significantly higher than that ofthecontrol, which is because thinning blossoms and fruit reduces the tree load, and leaves can use CO₂ more efficiently, increasing carbon assimilation efficiency and mitigating the decrease of assimilation product due to the decreased Pn and the accumulation of fruit sucrose (DeJong, 1986; Duan et al., 2008; Cheng et al., 2009). Sucrose is the main carbohydrate form transported from leaves to fruit (Li et al., 2021). The data in Tables 2 and 4 also show that with fruit growth and development, the sucrose content of each treatment gradually increased, whereas the glucose, fructose, and sorbitol contents decreased. The increase in sucrose content of the blossom- and fruit-thinning treatments was greater than that of thecontrol, and reducing the tree load effectively regulated the accumulation of carbohydrates, revealing a greater carbon-sink capacity.

Conclusions

When adjusting the load of ‘Xiahui 5’ peach trees planted in the middle and lower reaches of the Yangtze River in China by thinning blossoms and fruit, thinning fruit twice (fruit-thinning 20 DAFB+fruit-thinning 40 DAFB) to a spacing of 20cm between fruit on the same bearing branch during the young fruit period and before entering the core-hardening period saved labour, improved the weights of individual fruit, the yield, and the internal fruit quality (SSC and sugartoacid ratio) and external fruit quality (L*, a*, and a/b), as well as enhancing the WUE and CUE_app values of leaves, which reduced the main organic acid content. Thus, thinning fruit twice (20 DAFB+40 DAFB) during the young fruit period is a blossom- and fruit-management method suitable for peach production areas in the middle and lower reaches of the Yangtze River in China.

Acknowledgements

We would like to thank all our colleagues for their helpful discussions and assistance. We thank International Science Editing for linguistic assistance during the preparation of this manuscript.

Funding

This work was supported by the China Agriculture Research System (No.CARS-30) and the Earmarked Fund for Jiangsu Agricultural Industry Technology System (Nos.JATS[2020]379, JATS[2021]425, andJATS[2022]426), China.

Author Contributions

Binbin Zhang: Methodology, investigation, formal analysis, andwriting original draft. Shaolei Guo: Investigation and software. Xiaojun Wang: Formal analysis and data curation. Meng Sun: Data curation. Yuanyuan Zhang: Data curation. Hong Chen: Data curation. Mingliang Yu: Reviewing and editing, funding acquisition, andresources. Ruijuan Ma: Reviewing and editing and funding acquisition.

Conflict of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

© The Author(s) 2024. Published by Oxford University Press on behalf of Zhejiang University Press.

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