Method for evaluating citrus fruit cracking and use thereof

Abstract

The present application relates to the technical field of citrus fruit cracking evaluation, and specifically to a method for evaluating citrus fruit cracking. According to the present application, five indicators that can be used for evaluating citrus fruit cracking are determined, and correlation analysis between the five indicators and field experimental data on a citrus fruit cracking rate is performed, indicating that the five indicators are positively correlated with the fruit cracking rate. By measuring the five indicators, the association between fruit cracking characteristics and conditions such as varieties and cultivation conditions can be accurately described, allowing for fundamental understanding of causes of fruit cracking; moreover, the five indicators are easy to measure, and can be used for testing both fruits on unharvested trees and post-harvest fruits, helping to reflect the fruit cracking situation and find more accurate measures to reduce fruit cracking. The present application provides technical support for improving the fruit cracking resistance of varieties by means of breeding, or for guiding measures to prevent fruit cracking, including applying certain fertilizers or reducing irrigation.

Description

A method for evaluating citrus fruit cracking and its application

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on March 26, 2024, with application number CN202410353809.6 and invention name “A method for evaluating citrus fruit cracking and its application”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the technical field of citrus fruit cracking evaluation, and specifically relates to a method for evaluating citrus fruit cracking. Background Art

[0003] Citrus fruit cracking is a common physiological disease of citrus fruits. It usually occurs when the fruit is ripe and is characterized by cracks in the peel, exposing the flesh. This condition has an adverse impact on the quality and market value of citrus fruits, including the following aspects: (1) Quality loss: Cracked peels will deteriorate the appearance of the fruit, affecting the sales value of citrus fruits. Consumers usually prefer to buy fruits with intact appearance; (2) Susceptibility to pathogens: Cracks become channels for pathogens to invade, increasing the risk of fruit being attacked by pathogens such as fungi and bacteria; (3) Water loss: Cracked peels will cause the fruit to lose water, affecting taste and storage performance; (4) Poor eating experience: Fruit cracking often causes the flesh to become uneven, which may affect the eating experience; (5) Yield reduction: If a large number of fruits are affected by fruit cracking, the overall yield may be affected.

[0004] Currently, the evaluation of citrus fruit cracking is primarily based on field observations, using the ratio of cracked fruit to total fruit count on a single tree. A method for quantifying the impact of individual fruit is lacking. This crude metric fails to capture the relationship between variety, management level, and environmental factors. For example, the fruit cracking rate of some citrus fruits can be as high as 80%, with variations across years, regions, and orchard management levels. This suggests that fruit cracking is a complex trait influenced by multiple factors. A single fruit cracking rate alone cannot fully assess the problem; a more accurate, multidimensional descriptive approach is needed.

[0005] The occurrence of citrus fruit cracking is usually related to the following factors: (1) Improper water management: Excessive or insufficient irrigation may cause citrus fruit to crack; (2) Climatic factors: Sudden changes in climatic conditions such as humidity and temperature may trigger fruit cracking; (3) Nutritional imbalance: Excessive or insufficient supply of nutrients may also cause fruit cracking; (4) Pests and diseases: Certain pests and diseases may cause the fruit peel to crack, providing opportunities for pathogens to invade; However, citrus fruit cracking is usually the result of the combined action of multiple factors, and accurate and quantifiable descriptive indicators and methods are needed to understand which aspects of the fruit are related to fruit cracking.

[0006] Summary of the Invention

[0007] The purpose of this application is to provide a method for evaluating citrus fruit cracking, which can not only quantitatively describe the quality of the citrus fruit itself, but also show a correlation with the citrus fruit cracking rate in the field, fundamentally understand the causes of fruit cracking, and then guide practice.

[0008] This application provides the application of one or more of the following five indicators in evaluating citrus fruit cracking;

[0009] The five indicators include peel hardness, fruit turgor pressure, fruit cracking position when fruit turgor pressure reaches the limit, water injection volume at the fruit limit turgor pressure and fruit cracking ratio index;

[0010] The fruit turgor pressure is the pressure generated inside the citrus fruit when water is injected into the citrus fruit from the center of the fruit to cause the fruit to rupture.

[0011] The cracking position when the fruit turgor pressure reaches the limit is the position where the citrus fruit breaks. The cracking position when the fruit turgor pressure reaches the limit is quantified by scoring. Cracking on the equatorial plane of the peel is scored as 5 points, cracking between the equatorial plane of the fruit and the fruit pedicle or navel is scored as 4 points, cracking around the navel is scored as 3 points, cracking around the navel is scored as 2 points, cracking on the fruit pedicle is scored as 1 point, if there is a wound on the fruit, it is scored as 0 points, and cracking around the needle tip is scored as 0 points.

[0012] The water injection volume at the fruit's ultimate turgor pressure is the water injection volume when the citrus fruit ruptures;

[0013] The method for determining the fruit cracking ratio index comprises: injecting 5% to 15% of the weight of the fruit through the fruit pedicle; the ratio of the number of peel cracks to the total number of water-injected fruits within 24 hours is the peel cracking ratio Cr of the fruit after water injection; and calculating the fruit cracking ratio index according to a predetermined formula based on the peel cracking ratio Cr of the fruit after water injection, the peel cracking position score S, and the time t when the peel cracks:

[0014] Fruit cracking ratio index = 0.347 × (25-t) × (1+S) × (1+Cr); the score S for the peel cracking position is the same as the scoring method for the fruit cracking position when the fruit turgor pressure reaches the limit; the time t when the peel cracks is the tth hour after water is injected into the fruit.

[0015] Preferably, the peel hardness includes the peel hardness of the whole fruit and the peel hardness of the in vitro fruit; the peel hardness is measured using a texture analyzer, and the measurement depth is 3 to 8 mm.

[0016] Preferably, the probe diameter of the texture analyzer is 2 mm and the travel speed is 1.0 mm / s.

[0017] Preferably, the peel hardness is negatively correlated with the fruit cracking rate of citrus fruits.

[0018] Preferably, the fruit turgor pressure, the water injection volume at the fruit's limit turgor pressure and the fruit cracking rate of the citrus fruit are negatively correlated, respectively; the fruit cracking position when the fruit turgor pressure reaches the limit is positively correlated with the fruit cracking rate of the citrus fruit.

[0019] Preferably, the fruit cracking ratio index is positively correlated with the fruit cracking rate of citrus fruits.

[0020] The present application also provides a method for evaluating citrus fruit cracking, which evaluates the citrus fruit cracking by measuring one or more of the following five indicators:

[0021] The five indicators include peel hardness, fruit turgor pressure, fruit cracking position when fruit turgor pressure reaches the limit, water injection volume at the fruit limit turgor pressure and fruit cracking ratio index;

[0022] The fruit turgor pressure is the pressure generated inside the citrus fruit when water is injected into the citrus fruit from the center of the fruit to cause the fruit to rupture.

[0023] The cracking position when the fruit turgor pressure reaches the limit is the position where the citrus fruit breaks. The cracking position when the fruit turgor pressure reaches the limit is quantified by scoring. Cracking on the equatorial plane of the peel is scored as 5 points, cracking between the equatorial plane of the fruit and the fruit pedicle or navel is scored as 4 points, cracking around the navel is scored as 3 points, cracking around the navel is scored as 2 points, cracking on the fruit pedicle is scored as 1 point, if there is a wound on the fruit, it is scored as 0 points, and cracking around the needle tip is scored as 0 points.

[0024] The water injection volume at the fruit's ultimate turgor pressure is the water injection volume when the citrus fruit ruptures;

[0025] The method for determining the fruit cracking ratio index comprises: injecting 5% to 15% of the weight of the fruit through the fruit pedicle; the ratio of the number of peel cracks to the total number of water-injected fruits within 24 hours is the peel cracking ratio Cr of the fruit after water injection; and calculating the fruit cracking ratio index according to a predetermined formula based on the peel cracking ratio Cr of the fruit after water injection, the peel cracking position score S, and the time t when the peel cracks:

[0026] Fruit cracking ratio index = 0.347 × (25 - t) × (1 + S) × (1 + Cr); the score S for the peel cracking position is the same as the scoring method for the fruit cracking position when the fruit turgor pressure reaches the limit; the time t when the peel cracks is the tth hour after water is injected into the fruit;

[0027] The peel hardness, fruit turgor pressure, and water injection volume at the fruit's ultimate turgor pressure are negatively correlated with the fruit cracking rate of citrus fruits.

[0028] The fruit cracking position and the fruit cracking ratio index when the fruit turgor pressure reaches the limit are positively correlated with the fruit cracking rate of the citrus fruit.

[0029] Preferably, the method for measuring the fruit turgor pressure includes: connecting one end of a water injection tube with a water pressure gauge to a syringe needle, and connecting the other end to a syringe; inserting the syringe needle into a citrus fruit and reaching the stele of the citrus fruit, using a syringe to inject water into the citrus fruit, and when the citrus fruit breaks, the pressure value displayed by the water pressure gauge is the fruit turgor pressure.

[0030] The present application also provides the application of the method described in the above technical solution in citrus breeding and / or cultivation.

[0031] Preferably, the cultivation includes preventing and controlling citrus fruit cracking and / or water and fertilizer management. Beneficial effects:

[0032] The present application provides the application of peel hardness, fruit turgor pressure, fruit cracking position when fruit turgor pressure reaches the limit, water injection volume at the limit turgor pressure of the fruit and fruit cracking ratio index in evaluating citrus fruit cracking. The present application identifies five indicators that can be used to evaluate citrus fruit cracking, and conducts correlation analysis with field experimental data of citrus fruit cracking rate, indicating that these five indicators are positively correlated with the fruit cracking rate. By detecting these five indicators, the relationship between the fruit cracking characteristics and the variety, cultivation and other conditions can be accurately described, and the cause of fruit cracking can be fundamentally understood; and the five indicators are easy to detect, and can be used to detect fruits on unpicked fruit trees as well as fruits after harvest, which helps to reflect the fruit cracking situation and find more accurate measures to reduce fruit cracking. It provides indicators for detection and / or reference for improving the fruit cracking characteristics of the variety itself through breeding, or guiding measures to prevent and control fruit cracking, including applying certain fertilizers or reducing watering. DETAILED DESCRIPTION

[0033] This application provides the application of one or more of the following five indicators in evaluating citrus fruit cracking;

[0034] The five indicators include peel hardness, fruit turgor pressure, fruit cracking position when fruit turgor pressure reaches the limit, water injection volume at the fruit limit turgor pressure and fruit cracking ratio index;

[0035] The fruit turgor pressure is the pressure generated inside the citrus fruit when water is injected into the citrus fruit from the center of the fruit to cause the fruit to rupture.

[0036] The site of cracking when the fruit turgor pressure reaches the limit is the location where the citrus fruit breaks. The site of cracking when the fruit turgor pressure reaches the limit is quantified by scoring, with cracking on the equatorial plane of the peel being scored as 5 points, cracking between the equatorial plane of the fruit and the fruit pedicle or navel being scored as 4 points, cracking around the navel being scored as 3 points, cracking around the navel being scored as 2 points, cracking at the fruit pedicle being scored as 1 point, wounds on the fruit being scored as 0 points, and cracking around the needle being scored as 0 points. The wounds on the fruit described in the present application are preferably caused by the needle or other reasons during the water injection process. The cracking is preferably caused by the fruit turgor pressure, which can simulate the real fruit cracking process. Furthermore, the wounds and cracking are clearly distinguishable and can be routinely identified by those skilled in the art.

[0037] The water injection volume at the fruit's ultimate turgor pressure is the water injection volume when the citrus fruit ruptures;

[0038] The method for determining the fruit cracking ratio index comprises: injecting 5% to 15% of the weight of the fruit through the fruit pedicle; the ratio of the number of fruit peels that crack within 24 hours to the total number of water-injected fruits is the fruit peel cracking ratio (Cr); and the fruit cracking ratio index is calculated according to a predetermined formula based on the fruit peel cracking ratio Cr, the fruit peel cracking position score S, and the time t when the fruit peel cracks:

[0039] Fruit cracking ratio index = 0.347 × (25-t) × (1+S) × (1+Cr); the score S for the peel cracking position is the same as the scoring method for the fruit cracking position when the fruit turgor pressure reaches the limit; the time t when the peel cracks is the tth hour after water is injected into the fruit.

[0040] In the present application, the peel hardness preferably includes the peel hardness of the intact fruit and the peel hardness of the isolated fruit. The present application preferably uses a texture analyzer to measure the peel hardness. The brand and model of the texture analyzer are not particularly limited, and a conventional texture analyzer in the field can be used for measurement. For example, in the examples of the present application, a texture analyzer model TA-XT plus 40738 from Stable Micro Systems (UK) is used. The measurement depth is preferably 3 to 8 mm, more preferably 5 mm. The measurement depth has the advantage of being consistent with the thickness of most peels and having high data repeatability. The probe diameter of the measurement is preferably 2 mm, and the speed is preferably 1.0 mm / s. When measuring the peel hardness of the intact fruit, the present application preferably selects two symmetrical points on the equatorial plane for detection, and takes the average value as the peel hardness of the intact fruit measured in one measurement. When measuring the isolated peel hardness, it is preferably a square of peel tissue with a side length of 1 to 3 cm, preferably a square with a side length of 2 cm, with the white skin of the peel facing up.

[0041] In the present application, the method for measuring the fruit turgor pressure preferably includes: connecting one end of a water injection tube with a water pressure gauge to a syringe needle, and connecting the other end to a syringe; inserting the syringe needle into the citrus fruit and reaching the center of the citrus fruit, using a syringe to inject water into the citrus fruit, and when the citrus fruit breaks, the pressure value displayed by the water pressure gauge is the fruit turgor pressure.

[0042] The amount of water injected when the citrus fruit is ruptured in the present application is the water injection volume at the fruit's limit turgor pressure.

[0043] In the present application, a method for determining a cracked fruit ratio index comprises: injecting 5% to 15% of the weight of the fruit through the fruit pedicle; the ratio of the number of peel cracks to the total number of water-injected fruits within 24 hours is the peel cracking ratio Cr of the fruit after water injection; and calculating the cracked fruit ratio index according to a predetermined formula based on the peel cracking ratio Cr of the fruit after water injection, the peel cracking position score S, and the time t when the peel cracks:

[0044] Fruit cracking ratio index = 0.347 × (25-t) × (1+S) × (1+Cr); the scoring method of the peel cracking position S is the same as the scoring method of the fruit cracking position when the fruit turgor pressure reaches the limit.

[0045] The weight of the water in the present application is preferably 10% of the weight of the fruit. The time t for peel dehiscence in the present application is preferably an integer between 1 and 24, with the specific rules explained as follows: dehiscence within 0-1 hour is recorded as 1, dehiscence within 1-2 hours is recorded as 2, dehiscence within 2-3 hours is recorded as 3, dehiscence within 3-4 hours is recorded as 4...dehiscence within 22-23 hours is recorded as 23, dehiscence within 23-24 hours is recorded as 24, and dehiscence within >24 hours or no dehiscence is recorded as 24.

[0046] In the present application, the peel hardness is preferably negatively correlated with the fruit cracking rate of citrus fruit, that is, the higher the hardness of the peel hardness, the lower the fruit cracking rate of citrus fruit; the fruit turgor pressure is preferably negatively correlated with the fruit cracking rate of citrus fruit, that is, the higher the fruit turgor pressure, the lower the fruit cracking rate of citrus fruit; the water injection volume at the fruit limit turgor pressure is preferably negatively correlated with the fruit cracking rate of citrus fruit, that is, the larger the water injection volume at the fruit limit turgor pressure, the lower the fruit cracking rate of citrus fruit; the fruit cracking position when the fruit turgor pressure reaches the limit is preferably positively correlated with the fruit cracking rate of citrus fruit, that is, the higher the score of the fruit cracking position when the fruit turgor pressure reaches the limit, the higher the fruit cracking rate of citrus fruit; the fruit cracking ratio index is preferably positively correlated with the fruit cracking rate of citrus fruit, that is, the higher the fruit cracking ratio index is.

[0047] The present application also provides a method for evaluating citrus fruit cracking, which evaluates the citrus fruit cracking by measuring one or more of the following five indicators:

[0048] The five indicators include peel hardness, fruit turgor pressure, fruit cracking position when fruit turgor pressure reaches the limit, water injection volume at the fruit limit turgor pressure and fruit cracking ratio index;

[0049] The fruit turgor pressure is the pressure generated inside the citrus fruit when water is injected into the citrus fruit from the center of the fruit to cause the fruit to rupture.

[0050] The cracking position when the fruit turgor pressure reaches the limit is the position where the citrus fruit breaks. The cracking position when the fruit turgor pressure reaches the limit is quantified by scoring. Cracking on the equatorial plane of the peel is scored as 5 points, cracking between the equatorial plane of the fruit and the fruit pedicle or navel is scored as 4 points, cracking around the navel is scored as 3 points, cracking around the navel is scored as 2 points, cracking on the fruit pedicle is scored as 1 point, if there is a wound on the fruit, it is scored as 0 points, and cracking around the needle tip is scored as 0 points.

[0051] The water injection volume at the fruit's ultimate turgor pressure is the water injection volume when the citrus fruit ruptures;

[0052] The method for determining the fruit cracking ratio index comprises: injecting 5% to 15% of the weight of the fruit through the fruit pedicle; the ratio of the number of peel cracks to the total number of water-injected fruits within 24 hours is the peel cracking ratio Cr of the fruit after water injection; and calculating the fruit cracking ratio index according to a predetermined formula based on the peel cracking ratio Cr of the fruit after water injection, the peel cracking position score S, and the time t when the peel cracks:

[0053] Fruit cracking ratio index = 0.347 × (25 - t) × (1 + S) × (1 + Cr); the score S for the peel cracking position is the same as the scoring method for the fruit cracking position when the fruit turgor pressure reaches the limit; the time t when the peel cracks is the tth hour after water is injected into the fruit;

[0054] The peel hardness, fruit turgor pressure, and water injection volume at the fruit's ultimate turgor pressure are negatively correlated with the fruit cracking rate of citrus fruits.

[0055] The fruit cracking position and the fruit cracking ratio index when the fruit turgor pressure reaches the limit are positively correlated with the fruit cracking rate of the citrus fruit.

[0056] The measurement process and parameters of the five indicators described in this application have been optimized and limited in the above technical solution and will not be repeated here.

[0057] The higher the hardness of the peel hardness described in this application, the lower the cracking rate of the citrus fruit; the higher the hardness of the peel hardness, the lower the cracking rate of the citrus fruit; the larger the water injection volume at the limit turgor pressure of the fruit, the lower the cracking rate of the citrus fruit; the higher the score of the cracking position when the fruit turgor pressure reaches the limit, the higher the cracking rate of the citrus fruit; the higher the cracking ratio index, the higher the cracking rate of the citrus fruit.

[0058] When evaluating citrus fruit cracking using the method described herein, it is preferred to select a statistically significant number of trees for testing based on the actual size of the orchard. Of the five indicators described, peel hardness is preferably measured using a single group of citrus fruits; fruit turgor pressure, the location of cracking when fruit turgor pressure reaches its limit, and the water injection volume at maximum turgor pressure are preferably measured using a single group of fruits; and the fruit cracking ratio index is preferably measured using a single group of fruits, with a statistically significant number of biological replicates preferably set within each group.

[0059] This application identifies five indicators that can be used to evaluate citrus fruit cracking, and conducts a correlation analysis with field experimental data on citrus fruit cracking rates, indicating that these five indicators are positively correlated with the fruit cracking rate. By detecting these five indicators, it is possible to accurately describe the relationship between the fruit cracking characteristics and conditions such as variety and cultivation, and fundamentally understand the causes of fruit cracking; and the five indicators are easy to detect, and can be used to detect both unharvested fruit on fruit trees and harvested fruit, which helps to reflect the fruit cracking situation and find more accurate measures to reduce fruit cracking. This provides technical support for improving the variety's own fruit cracking characteristics through breeding, or guiding measures to prevent and control fruit cracking, including applying certain fertilizers or reducing watering.

[0060] Based on the above advantages, the present application also provides the application of the method described in the above technical solution in citrus breeding and / or cultivation, preferably in citrus breeding and cultivation. The cultivation described in the present application preferably includes preventing and controlling citrus fruit cracking and / or water and fertilizer management, more preferably preventing and controlling citrus fruit cracking and water and fertilizer management.

[0061] In order to further illustrate the present application, the technical solutions provided in the present application are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0062] Example 1

[0063] The evaluation of fruit cracking among different trees of the citrus variety 'Ganping' with a high fruit cracking rate was conducted as follows:

[0064] In the Ganping orchard in Xiangshan County, Ningbo, Zhejiang Province, 10 fruit trees were randomly selected (out of a total of 200 trees in the orchard). The fruit cracking rate of these 10 trees was recorded in August (50 fruits per tree, for a total of 10 trees, the fruit cracking rate of each tree was averaged).

[0065] Thirty citrus fruits were randomly selected from each fruit tree as the evaluation group. The fruit turgor pressure, the location of the cracked fruit when the fruit turgor pressure reached the limit, the water injection volume at the limit of the fruit turgor pressure, and the fruit cracking ratio index after a certain amount of water injection were tested in the orchard. The peel hardness test was carried out in the laboratory. The fruit turgor pressure, the location of the cracked fruit when the fruit turgor pressure reached the limit, and the water injection volume at the limit of the fruit turgor pressure were tested on the same 10 citrus fruits; the peel hardness was tested on 10 citrus fruits; the fruit cracking ratio index after a certain amount of water injection was tested on 10 citrus fruits.

[0066] Detection method:

[0067] (1) Peel hardness, including the peel hardness of intact fruit and the peel hardness of isolated fruit

[0068] Intact Fruit Peel Firmness: Citrus fruit firmness was measured using a texture analyzer (TA-XT plus 40738, Stable Micro Systems, UK) with a probe diameter of 2 mm, a measurement depth of 5 mm, and a measurement speed of 1.0 mm / s. Ten fruits of each citrus variety were tested at two symmetrical points along the equatorial plane.

[0069] In vitro peel hardness: Carefully peel the peel and take a 2 cm square of peel tissue. Place it on the same hard plastic plate with the white peel facing upwards. Use the same texture analyzer to measure the hardness of the citrus fruit. The probe used is 2 mm in diameter, the measurement depth is 5 mm, and the measurement speed is 1.0 mm / s.

[0070] Ten fruits were tested on each tree, and both intact peel hardness and in vitro peel hardness were measured on the same fruit.

[0071] (2) Fruit turgor pressure

[0072] Fruit turgor pressure is tested using the water injection method. A syringe needle is connected to a hose, which is then connected to a water pressure gauge. The other end of the hose is connected to a 50mL syringe. During the test, a press is used to insert the needle into the fruit near the stem, allowing the needle to reach the center of the citrus fruit. Water is then injected into the fruit using a syringe. The reaction force from the injection creates pressure inside the fruit, which is recorded by the water pressure gauge. When the water injection reaches the maximum amount and the fruit ruptures, the maximum pressure displayed on the water pressure gauge is the maximum turgor pressure the fruit can withstand.

[0073] (3) Fruit cracking position when fruit turgor pressure reaches the limit

[0074] When turgor pressure reaches its maximum, the peel will crack, and turgor pressure will drop sharply. The location of the peel cracking at this point is the site of cracking when turgor pressure reaches its limit. Cracking at the equatorial plane of the peel is scored as 5 points, cracking between the equatorial plane and the pedicle or navel is scored as 4 points, cracking around the navel is scored as 3 points, cracking at the navel is scored as 2 points, and cracking at the pedicle is scored as 1 point. Any wound on the fruit is scored as 0 points, as is cracking around the needle tip.

[0075] (4) Water injection volume at the fruit's maximum turgor pressure

[0076] The volume of water injected from the start of water injection until the turgor pressure in the fruit reaches its maximum value and the peel cracks is the water injection volume at the fruit's limit turgor pressure.

[0077] (5) The proportion of fruit peel cracking after a certain amount of water injection

[0078] The cracking ratio (proportion index) is calculated by injecting 10% of the fruit's weight of water into the fruit's base. The ratio of the number of fruit peels that crack within 24 hours to the total number of fruit injected with water is the cracking ratio. The proportion index is calculated as: Pi = 0.347 × (25 - t) × (1 + S) × (1 + Cr), where t is the time to peel cracking, S is the peel cracking location score (score is the same as in step 3), and Cr is the fruit cracking ratio.

[0079] The results are shown in Table 1 and Table 2:

[0080] Table 1 Evaluation indexes of fruit cracking in 'Ganping' citrus fruit

[0081] Table 2 Correlation analysis between fruit cracking indexes and fruit cracking rate of 'Ganping'

[0082] As shown in Table 1, several indicators were used to evaluate Ganping fruit cracking. Both intact and in vitro peel hardness tests were conducted in the laboratory. The average intact peel hardness of the 10 trees ranged from 6.30 to 14.30 N, while the in vitro peel hardness ranged from 1.07 to 2.85 N. Both indicators were negatively correlated with the fruit cracking rate of the corresponding trees, with correlations of 0.82 and 0.85, respectively. Fruit turgor pressure, average fruit cracking position, water injection volume at extreme turgor pressure, and fruit cracking ratio index when a certain volume is injected are all directly tested on the fruit trees. Among them, fruit turgor pressure directly reflects the maximum internal pressure that the peel can withstand, which is 18.51~59.14kPa. The position of fruit cracking determines the vulnerable parts inside the peel. Among them, most Ganping fruits crack at the equatorial plane, and its index is 2.99~4.78. The water injection volume at maximum turgor pressure determines the maximum volume that the fruit can withstand, which is 12.80~44.89mL. When 10% of the fruit weight of water is injected, most Ganping fruits crack within 1 hour, the cracking ratio reaches more than 90%, and its cracking ratio index is 64.32~96.26.

[0083] The average intact peel hardness, average in vitro peel hardness, fruit turgor pressure, average fruit cracking position, water injection volume at the limit turgor pressure, and proportion index measured in Table 1 were respectively subjected to correlation analysis with the fruit cracking rate. The specific method was to draw a point graph with the fruit cracking index as the horizontal axis and the fruit cracking rate as the vertical axis, then add a trend line, and display the obtained R 2 Value, R 2 The larger the value, the higher the correlation between fruit indicators and fruit cracking rate. The results are shown in Table 2. Correlation analysis with fruit cracking rate found that fruit turgor pressure and water injection volume at extreme turgor pressure were negatively correlated with fruit cracking rate, with correlation coefficients of 0.90 and 0.75 respectively. The average fruit cracking position and fruit cracking ratio index were positively correlated with fruit cracking rate, with correlation coefficients of 0.84 and 0.79 respectively.

[0084] The above results show that indicators such as peel hardness, fruit turgor pressure, average fruit cracking position, water injection volume at maximum turgor pressure and fruit cracking ratio index can reflect the level of fruit cracking rate and provide a quantifiable supplement to the fruit cracking rate.

[0085] Example 2

[0086] The evaluation of post-harvest fruit cracking of 'Ganping' mandarins among different trees in the same orchard was conducted as follows:

[0087] In the Ganping orchard in Quzhou City, Zhejiang Province, 10 fruit trees were randomly selected and their fruit cracking rates were recorded in August (50 fruits were counted per tree, and the fruit cracking rates of 10 trees were averaged).

[0088] Thirty citrus fruits were randomly selected from each fruit tree as an evaluation group, and the peel hardness, fruit turgor pressure, the position of fruit cracking when the fruit turgor pressure reached the limit, the water injection volume at the fruit's limit turgor pressure, and the fruit cracking ratio index after a certain amount of water injection were tested in the laboratory.

[0089] The detection method is shown in Example 1, and the results are shown in Tables 3 and 4:

[0090] Table 3 Evaluation indexes of fruit cracking in 'Ganping' citrus fruits

[0091] Table 4 Correlation analysis between fruit cracking indexes and fruit cracking rate of 'Ganping'

[0092] As shown in Table 3, several indicators were used to evaluate the cracking of harvested Ganping fruit. All indicators were tested in the laboratory. The results showed that the average intact peel hardness of harvested Ganping fruit ranged from 6.67 to 12.44 N, while the in vitro peel hardness ranged from 1.73 to 3.19 N. Both values ​​were negatively correlated with the cracking rate of the corresponding trees, with correlations of 0.81 and 0.82, respectively. Fruit turgor pressure values ​​ranged from 20.17 to 60.48 kPa. The location of cracking determined the vulnerable area within the peel. Most Ganping fruit cracked at the equatorial plane, with an index ranging from 3.02 to 4.97. The water volume injected at maximum turgor pressure, which determined the maximum volume the fruit could withstand, ranged from 21.66 to 48.33 mL. After injection of 10% of the fruit weight with water, most Ganping fruits cracked within 1 hour, with the cracking rate exceeding 90%, and the cracking ratio index ranging from 66.99 to 94.77.

[0093] As shown in Table 4, the correlation analysis with the fruit cracking rate found that the fruit turgor pressure and the water injection volume at the limit turgor pressure were negatively correlated with the fruit cracking rate, with correlation coefficients of 0.88. The average fruit cracking position and the fruit cracking ratio index were positively correlated with the fruit cracking rate, with correlation coefficients of 0.80 and 0.82.

[0094] The above results show that under post-harvest conditions, the indicators such as peel hardness, fruit turgor pressure, average fruit cracking position, water injection volume at maximum turgor pressure and fruit cracking ratio index in this method can also accurately reflect the level of fruit cracking rate and provide a quantifiable supplement to the fruit cracking rate.

[0095] Example 3

[0096] The evaluation of fruit cracking among different citrus varieties is as follows:

[0097] Methods: Ten citrus varieties, including 'Ganping', 'Hongmeiren', 'Ashirimi', 'Hongying', 'Eureka', 'Wogan', 'Chunjian', 'Moyang Ponkan', 'Zijinougan', and 'Chazhigan', were selected from orchards of multiple citrus varieties in Taizhou City, Zhejiang Province. Ten trees of each variety were randomly selected, and the fruit cracking rate of these 10 trees was recorded in August (30 fruits per tree, for a total of 50 trees, and the fruit cracking rate of each tree was averaged).

[0098] Thirty citrus fruits were randomly selected from each fruit tree as the evaluation group. The peel hardness, fruit turgor pressure, the position of fruit cracking when the fruit turgor pressure reached the limit, the water injection volume at the fruit limit turgor pressure and the fruit cracking ratio index after a certain amount of water injection were tested in the laboratory. The peel hardness test was carried out in the laboratory.

[0099] The detection method is shown in Example 1, and the results are shown in Tables 5 and 6:

[0100] Table 5 Peel hardness of 10 citrus varieties

[0101] Table 6 Correlation analysis between fruit cracking indexes and fruit cracking rates of 10 citrus varieties

[0102] As shown in Table 5, the fruit cracking rates and fruit cracking-related indices of 10 different citrus varieties were evaluated. The results showed that the average intact peel hardness of post-harvest citrus fruit ranged from 10.45 to 26.02 N. Among them, Ganping and Ashita, which had higher fruit cracking rates, had the lowest intact peel hardness, at 10.45 and 13.89 N, respectively. In vitro peel hardness ranged from 2.46 to 5.35 N, with Ganping and Ashita, which had higher fruit cracking rates, also having the lowest in vitro peel hardness. Both intact and in vitro peel hardness showed a negative correlation with the fruit cracking rate of the corresponding trees, with a correlation of 0.87 in both cases. Fruit turgor pressure ranged from 39.78 to 114.31 kPa, with Ganping and Ashita having the lowest turgor pressures, at 39.78 and 70.24 kPa, respectively. The location of fruit cracking determines the vulnerable areas within the peel, with an index ranging from 0.25 to 4.80. Among varieties with lower cracking rates, such as Zijinou, Chazhi, Moyang, and Eureka, cracking is concentrated around the needle tip or in the pedicle, resulting in lower indices. The volume of water injected at maximum turgor pressure determines the maximum volume the fruit can withstand, ranging from 20.97 to 43.81 mL. When 10% of the fruit's weight of water is injected, the cracking ratio index ranges from 17.66 to 96.60, with Ganping reaching 96.60. Varieties with lower cracking rates, such as Zijinou, Chazhi, and Eureka, all have cracking ratios below 30%.

[0103] As shown in Table 6, the correlation analysis with the fruit cracking rate found that the fruit turgor pressure and the water injection volume at the limit turgor pressure were negatively correlated with the fruit cracking rate, with correlation coefficients of 0.86. The average fruit cracking position and the fruit cracking ratio index were positively correlated with the fruit cracking rate, with correlation coefficients of 0.90 and 0.89.

[0104] The above results show that for different citrus varieties, the indicators of peel hardness, fruit turgor pressure, average fruit cracking position, water injection volume at extreme turgor pressure and fruit cracking ratio index in the method described in this application can also accurately reflect the level of fruit cracking rate and provide a quantifiable supplement to the fruit cracking rate.

[0105] Although the above embodiment provides a detailed description of the present application, it is only a part of the embodiments of the present application, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present application.

Claims

1. Application of one or more of the following five indicators in the evaluation of citrus fruit cracking; The five indicators include peel hardness, fruit turgor pressure, fruit cracking position when fruit turgor pressure reaches the limit, water injection volume at the fruit limit turgor pressure and fruit cracking ratio index; The fruit turgor pressure is the pressure generated inside the citrus fruit when water is injected into the citrus fruit from the pith to cause the fruit to rupture. The cracking position when the fruit turgor pressure reaches the limit is the position where the citrus fruit breaks. The cracking position when the fruit turgor pressure reaches the limit is quantified by scoring. Cracking on the equatorial plane of the peel is scored as 5 points, cracking between the equatorial plane of the fruit and the fruit pedicle or navel is scored as 4 points, cracking around the navel is scored as 3 points, cracking around the navel is scored as 2 points, cracking on the fruit pedicle is scored as 1 point, if there is a wound on the fruit, it is scored as 0 points, and cracking around the needle tip is scored as 0 points. The water injection volume at the fruit's ultimate turgor pressure is the water injection volume when the citrus fruit ruptures; The method for determining the fruit cracking ratio index comprises: injecting 5% to 15% of the weight of the fruit through the fruit pedicle; the ratio of the number of peel cracks to the total number of water-injected fruits within 24 hours is the peel cracking ratio Cr of the fruit after water injection; and calculating the fruit cracking ratio index according to a predetermined formula based on the peel cracking ratio Cr of the fruit after water injection, the peel cracking position score S, and the time t when the peel cracks: Fruit cracking ratio index = 0.347 × (25-t) × (1+S) × (1+Cr); the score S for the peel cracking position is the same as the scoring method for the fruit cracking position when the fruit turgor pressure reaches the limit; the time t when the peel cracks is the tth hour after water is injected into the fruit.

2. The use according to claim 1, characterized in that The peel hardness includes the peel hardness of the whole fruit and the peel hardness of the isolated fruit.

3. The use according to claim 1 or 2, characterized in that The method for measuring the peel hardness includes: measuring the peel hardness with a texture analyzer, and the measuring depth is 3 to 8 mm.

4. The use according to claim 3, characterized in that The probe diameter of the texture analyzer is 2 mm, and the travel speed is 1.0 mm / s.

5. The use according to claim 3, characterized in that When measuring the peel hardness of the whole fruit, two symmetrical points on the equatorial plane are selected for detection, and the average value is taken as the peel hardness of the whole fruit measured in one time.

6. The use according to claim 3, characterized in that When measuring the in vitro peel hardness, the peel tissue is square, the side length of the square is 1 to 3 cm, and the white skin of the peel is facing upward.

7. The use according to claim 1 or 2, characterized in that The peel hardness is negatively correlated with the fruit cracking rate of citrus fruits.

8. The use according to claim 1, characterized in that The fruit turgor pressure, the water injection volume at the fruit's limit turgor pressure, and the citrus fruit cracking rate are negatively correlated; the fruit cracking position when the fruit turgor pressure reaches the limit is positively correlated with the citrus fruit cracking rate.

9. The use according to claim 1, characterized in that The fruit cracking ratio index is positively correlated with the fruit cracking rate of citrus fruits.

10. The use according to claim 1, characterized in that The time t when the peel cracks is an integer between 1 and 24.

11. The use according to claim 1, characterized in that The method for measuring the fruit turgor pressure comprises: connecting one end of a water injection tube with a water pressure gauge to a syringe needle, and connecting the other end to a syringe; inserting the syringe needle into a citrus fruit and reaching the stele of the citrus fruit, injecting water into the citrus fruit using a syringe, and when the citrus fruit ruptures, the pressure value displayed by the water pressure gauge is the fruit turgor pressure.

12. A method for evaluating citrus fruit cracking, characterized in that: The cracking of citrus fruits was evaluated by measuring one or more of the following five indicators: The five indicators include peel hardness, fruit turgor pressure, fruit cracking position when fruit turgor pressure reaches the limit, water injection volume at the fruit limit turgor pressure and fruit cracking ratio index; The fruit turgor pressure is the pressure generated inside the citrus fruit when water is injected into the citrus fruit from the center of the fruit to cause the fruit to rupture. The cracking position when the fruit turgor pressure reaches the limit is the position where the citrus fruit breaks. The cracking position when the fruit turgor pressure reaches the limit is quantified by scoring. Cracking on the equatorial plane of the peel is scored as 5 points, cracking between the equatorial plane of the fruit and the fruit pedicle or navel is scored as 4 points, cracking around the navel is scored as 3 points, cracking around the navel is scored as 2 points, cracking on the fruit pedicle is scored as 1 point, if there is a wound on the fruit, it is scored as 0 points, and cracking around the needle tip is scored as 0 points. The water injection volume at the fruit's ultimate turgor pressure is the water injection volume when the citrus fruit ruptures; The method for determining the fruit cracking ratio index comprises: injecting 5% to 15% of the weight of the fruit through the fruit pedicle; the ratio of the number of peel cracks to the total number of water-injected fruits within 24 hours is the peel cracking ratio Cr of the fruit after water injection; and calculating the fruit cracking ratio index according to a predetermined formula based on the peel cracking ratio Cr of the fruit after water injection, the peel cracking position score S, and the time t when the peel cracks: Fruit cracking ratio index = 0.347 × (25 - t) × (1 + S) × (1 + Cr); the score S for the peel cracking position is the same as the scoring method for the fruit cracking position when the fruit turgor pressure reaches the limit; the time t when the peel cracks is the tth hour after water is injected into the fruit; The peel hardness, fruit turgor pressure, and water injection volume at the fruit's ultimate turgor pressure are negatively correlated with the fruit cracking rate of citrus fruits. The fruit cracking position and the fruit cracking ratio index when the fruit turgor pressure reaches the limit are positively correlated with the fruit cracking rate of the citrus fruit.

13. The method according to claim 12, characterized in that The method for measuring the fruit turgor pressure comprises: connecting one end of a water injection tube with a water pressure gauge to a syringe needle, and connecting the other end to a syringe; inserting the syringe needle into a citrus fruit and reaching the stele of the citrus fruit, injecting water into the citrus fruit using a syringe, and when the citrus fruit ruptures, the pressure value displayed by the water pressure gauge is the fruit turgor pressure.

14. Use of the method according to claim 12 or 13 in citrus breeding and / or cultivation.

15. The use according to claim 14, characterized in that The cultivation includes preventing and controlling citrus fruit cracking and / or water and fertilizer management.

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