A method for evaluating the productivity of sweet cherry

Abstract

The present application relates to the technical field of fruit tree planting, and particularly relates to a method for evaluating the high-yield property of sweet cherry. The present application provides a method for evaluating the high-yield property of sweet cherry, which comprises the following steps: grafting the sweet cherry scion to be evaluated onto a rootstock, waiting for the scion to develop to the flower separation period, counting the proportion of the number of flower buds containing 2-4 flowers in the total number of flower buds, and judging whether the sweet cherry to be evaluated is high-yield type according to the proportion value. The method provided by the present application takes the proportion of each flower bud containing 2-4 flowers in all flower buds in the sweet cherry new germplasm of the same tree age grafted onto different rootstocks (arborization rootstock, dwarfing rootstock) as the evaluation index, and rapidly identifies the high-yield property of the sweet cherry new germplasm. The method simplifies the identification process and greatly shortens the identification period.

Description

Technical Field

[0001] This invention relates to the field of fruit tree planting technology, and in particular to a method for evaluating the yield of sweet cherries. Background Technology

[0002] Sweet cherries, known as the "first fruit of spring," are highly favored by consumers due to their early ripening, high economic value, and suitability for sightseeing and picking. They have become an important economic and specialty tree species in various production areas and are also called the "fruit of prosperity." To date, the cultivated area in China exceeds 3.5 million mu (approximately 233,333 hectares), ranking first in the world. The planting area has also expanded from the Bohai Bay region to 25 provinces, municipalities, and autonomous regions, including along the Longhai Railway, high-altitude areas in the west, and cold regions in the northeast.

[0003] In sweet cherry production, yield is a prerequisite for achieving ideal economic benefits. Therefore, under the same favorable cultivation conditions (good irrigation and fertilization), the better the yield of a cultivar, the higher the yield. Thus, breeding high-yielding sweet cherry varieties is of great significance for maintaining stable sweet cherry production and improving economic benefits.

[0004] Every flower that can bear fruit is a fruit, and the number of flowers directly affects the yield of the fruit tree. The genetic characteristics of the cultivar and the rootstock are important factors influencing the number of flowers. We investigated six sweet cherry cultivars (Shamidou, Hongdeng, Changhua Zixia, Wanmilu, and Meizao) of the same age grafted onto Benxi Mountain Cherry rootstock (standard rootstock) and Gisela 6 rootstock (dwarfing rootstock) in the Qinhuangdao area. The results showed that the number of flowers per flower bud in most sweet cherry cultivars ranged from 1 to 4, with very few containing 5 flowers. Furthermore, we found that high-yielding varieties had a higher proportion of 2-4 flowers per flower bud than non-high-yielding varieties. On Benxi Mountain Cherry rootstock, the proportions of the six varieties with 2-4 flowers per flower bud were 93%, 78%, 69%, 68%, and 32%, respectively. On Gisela 6 rootstock, the proportions were 97%, 96%, 89%, 83%, and 67%, respectively. The yield potential of sweet cherries is primarily determined by varietal characteristics, and good cultivation management and suitable grafting rootstocks can enhance their yield. Therefore, in the breeding process of sweet cherries, the yield potential of a new cultivar can be judged by the proportion of 2-4 flowers per flower bud. This method simplifies the identification process, shortens the identification cycle, and is of great significance for the rapid screening of high-yielding sweet cherry germplasm.

[0005] Sweet cherries have a long juvenile stage, entering the fruiting period later than other stone fruit trees. However, determining whether a new cultivar is high-yielding requires it to reach its peak fruiting period. Using conventional breeding methods for sweet cherries, it generally takes 6-7 years from sowing to peak fruiting, a lengthy process that significantly prolongs the sweet cherry breeding time. Therefore, this invention is proposed. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for evaluating high-yielding sweet cherries. This method has a short breeding cycle and can screen out high-yielding varieties in the early stages of fruiting, thus greatly reducing the workload of breeding.

[0007] Specifically, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for evaluating the high yield of sweet cherries, comprising: grafting a sweet cherry scion to be evaluated onto a rootstock, waiting for the scion to develop to the inflorescence separation stage, counting the percentage of flower buds containing 2-4 flowers in the total number of flower buds, and determining whether the sweet cherry to be evaluated is high-yielding based on the percentage.

[0009] Preferably, the rootstock is a standard rootstock, and the judgment criteria include: if the percentage value is ≥65%, then the sweet cherry to be evaluated is judged to be a high-yielding type.

[0010] Preferably, the rootstock is a dwarfing rootstock, and the judgment criteria include: if the percentage value is ≥80%, then the sweet cherry to be evaluated is judged to be a high-yielding type.

[0011] Preferably, the rootstock includes standard rootstock and dwarf rootstock; the judgment criteria include: the proportion of flower buds with 2-4 flowers grafted onto standard rootstock is ≥65% of the total number of flower buds, and the proportion of flower buds with 2-4 flowers grafted onto dwarf rootstock is ≥80% of the total number of flower buds, then the sweet cherry to be evaluated is judged to be high-yielding.

[0012] Preferably, the standard rootstock is Benxi cherry rootstock; and / or, the dwarf rootstock is Gisela 6.

[0013] Preferably, grafting is performed when the rootstock seedlings grow to 0.6-1cm.

[0014] Preferably, a scion is used as a developing branch.

[0015] Preferably, grafting is performed by xylem budding.

[0016] Beneficial effects:

[0017] This invention provides a method for evaluating the yield potential of sweet cherry. The method involves grafting a sweet cherry scion to be evaluated onto a rootstock. Once the scion has developed to the inflorescence separation stage, the percentage of flower buds containing 2-4 flowers is counted out of the total number of flower buds. Based on this percentage, the high-yielding sweet cherry variety is determined. The method provided by this invention uses the proportion of each flower bud containing 2-4 flowers to all flower buds in new sweet cherry germplasm grafted onto different rootstocks (standard rootstock and dwarf rootstock) of the same age as the evaluation index for rapid identification of the yield potential of new sweet cherry germplasm. This method simplifies the identification process and significantly shortens the identification cycle. Detailed Implementation

[0018] This invention provides a method for evaluating the yield potential of sweet cherries. The method includes the following steps: (1) rootstock seedling preparation; (2) resource collection; (3) shaping and pruning; and (4) determination of flower bud flowering parameters. This method has the advantage of a short breeding cycle, and can screen out high-yielding germplasm at the early stage of fruiting, greatly reducing the amount of breeding work.

[0019] In a more specific embodiment of the present invention, the method for evaluating high-yielding sweet cherries is as follows:

[0020] (1) Preparation of rootstock seedlings:

[0021] Benxi Mountain Cherry rootstock seedling cultivation: In the spring of 2016, after the soil temperature at a depth of 5cm in the cold greenhouse stabilized above 5℃, select Benxi Mountain Cherry seeds of consistent origin for seed sowing. Use spot sowing, with holes 2-3cm deep. After sowing, use a wooden board to level the soil, ensuring the soil covers the seeds. Then cover the ground with plastic film to retain moisture. After the seeds germinate and emerge, remove the plastic film and erect a 50cm high arched greenhouse for insulation and moisture retention. Once the rootstock seedlings have lignified, make holes in the plastic film of the arched greenhouse for ventilation to begin acclimatization. Gradually increase the number of ventilation openings and the ventilation time. Acclimatization is complete in about 7 days. Transplant to the field and manage with regular water and fertilizer. Grafting is performed in early September of the same year when the rootstock seedlings reach 0.6-1cm in height. Early sowing in the cold greenhouse allows for earlier seedling emergence and grafting in the same year, shortening the identification period.

[0022] Gisela 6 rootstock cutting propagation: In mid-to-late August 2015, select healthy, disease-free, semi-lignified new shoots from the current year as cuttings. Before planting, trim the cuttings, making a slanted cut at the bottom. The cuttings should be 15-20cm long, retaining the top leaf center and 4-5 leaves. Immerse the lower end of the trimmed cuttings in a 1g / L IBA solution for 30 seconds, then insert them into sterilized substrate at a depth of 3-5cm. Cover the cutting shed with a shade net and install a misting system inside for cooling and humidification. Use a humidity controller to maintain humidity at around 98% and a temperature between 25-28℃. Roots will develop in 15 days. After rooting, reduce the humidity by 2% every 2 days. Once the humidity in the cutting shed reaches 70%, stop misting and gradually increase ventilation and light exposure until the shade net is removed. After the leaves fall in winter, the rootstock cuttings are removed from the substrate and buried in sand pits for frost protection. They are then transplanted to the field in April of the following year and managed with regular water and fertilizer. Grafting is carried out when the rootstock seedlings grow to 0.6-1cm in early September of the same year.

[0023] (2) Resource aggregation:

[0024] In early September 2016, robust, disease-free shoots from 11 main sweet cherry varieties (including 'Shamidou', 'Hongdeng', 'Meizao', and superior lines '219' (approved in 2020, Changhua Zixia), '793' (approved in 2020, Wanmilu), 'Dong8bei17', 'Dong6bei29', 'Dong6nan11', 'Dong8bei1', 'Dong6bei26', and 'Dong6nan5') were selected as scions. These were grafted onto Benxi Mountain Cherry rootstock and Gisela 6 rootstock using xylem budding. During winter, the grafts were buried 20cm above the bud for frost protection. Before bud break in spring 2017, the rootstock stem was cut 0.5-1cm above the bud. Afterward, any sprouts on the rootstock were promptly removed, and routine watering, fertilization, and pest and disease management were implemented. After the leaves fell in November 2016, the grafted seedlings were dug up and temporarily planted at an angle in a 1-meter-deep planting trench, and the soil was piled up to protect them from the cold.

[0025] In the spring of 2017, healthy grafted seedlings with plump buds, well-developed root systems, and no pests or diseases were selected and planted at the Science and Technology Innovation Base of Changli Fruit Tree Research Institute of Hebei Academy of Agricultural and Forestry Sciences, and routine soil, fertilizer and water management was carried out.

[0026] (3) Shaping and pruning:

[0027] The experimental seedlings were planted at a spacing of 3m × 4m, with a slender spindle shape. The specific shaping and pruning method was to not prune the seedlings after planting. The main trunk was promoted to grow new branches by notching buds and applying branching agent. That is, after the buds swelled, the buds within 50cm of the base of the main trunk were removed, leaving the terminal bud and two buds below it untreated. All the remaining buds on the main trunk were notched horizontally 0.5cm above the buds, deep into the xylem, and branching agent was applied to the buds at the same time.

[0028] When the newly sprouted branches are semi-lignified, use toothpicks or a branch-opening tool to prop open the branches, making it easier to train them later. Alternatively, when the branches reach about 30cm in length, hang bamboo clips at the ends to keep the branches nearly horizontal, and move the clips forward as the branches grow. In the spring of the following year, before bud break, thin out back branches and overly dense main branches, retaining one main branch approximately every 15cm, with each main branch spiraling upwards. For varieties (lines) grafted onto Benxi Mountain Cherry, control the tree height to 3.5m with approximately 20 main branches; for varieties (lines) grafted onto Gisela 6, control the tree height to 3m with approximately 15 main branches. After thinning out overly dense branches, train the branches to make them horizontal. Using this technique, the tree shape can be formed in 2 years, flower buds begin to form in the 3rd year, a small yield is produced in the 4th year, and the tree enters its peak production period in the 5th-6th year.

[0029] (4) Measurement of flowering parameters of flower buds

[0030] Among the collected germplasm, 'Shamidou', 'Hongdeng', '219' (Changhua Zixia) and '793' (Wanmilu) are high-yielding varieties; 'Meizao' is a variety with relatively poor yield. Superior lines 'Dong8bei17', 'Dong6bei29', 'Dong6nan11', 'Dong8bei1', 'Dong6bei26' and 'Dong6nan5' are superior lines awaiting evaluation.

[0031] In 2021, parameters were measured for flower buds of different rootstock-scion combinations planted for more than 4 years. The percentage of flower buds with 2-4 flowers per bud among all flower buds of different varieties grafted onto the same rootstock was used as the evaluation index. Based on the known number of flowers per flower bud in high-yielding and non-high-yielding varieties, the following were defined: high-yielding varieties of sweet cherry grafted onto the standard rootstock Benxi Mountain Cherry had a higher percentage of flower buds with 2-4 flowers per bud than 65%; high-yielding varieties of sweet cherry grafted onto the dwarf rootstock Gisela 6 had a higher percentage of flower buds with 2-4 flowers per bud than 80%.

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0033] The endpoints and any values ​​of the ranges disclosed in this specification are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "specific implementation," or "some specific implementations," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0035] In the embodiments provided in this specification, unless specific techniques or conditions are specified, the techniques or conditions described in the literature in this field, or the product instructions, shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0036] Example 1

[0037] In the spring of 2016, *Prunus cerasifera* rootstock for standardization was prepared through seed sowing, using the same method as the *Prunus cerasifera* rootstock seedling preparation mentioned above. In early September 2016, eleven varieties (lines) were grafted onto *Prunus cerasifera* rootstock using xylem budding: 'Shamidou', 'Hongdeng', 'Meizao', '219' (Changhua Zixia), '793' (Wanmilu), 'Dong8bei17', 'Dong6bei29', 'Dong6nan11', 'Dong8bei1', 'Dong6bei26', and 'Dong6nan5'. These were pruned to a slender spindle shape and managed with standard water, fertilizer, and flower / fruit care. In 2021, flower bud parameters were measured on the varieties (lines) with different rootstock-scion combinations that had been planted for four years. The specific measurement method is as follows: during the inflorescence separation period of each variety, the number of flower buds in each of 100 flower buds is randomly measured, and the proportion of different flower bud numbers in each flower bud is counted. The measurement results are shown in Table 1.

[0038] Table 1. Percentage of flowers per flower bud in varieties grafted onto Benxi cherry rootstock

[0039]

[0040] As shown in Table 1, among the 12 varieties (lines) grafted onto the standard rootstock *Prunus cerasifera* var. *benxi* evaluated, 'Shamidou', 'Hongdeng', 'Changhua Zixia', and 'Wanmilu' were high-yielding varieties, with 93%, 78%, 69%, and 68% of each flower bud containing 2-4 flowers, respectively; 'Meizao' was a lower-yielding variety, with 32% of each flower bud containing 2-4 flowers. Based on the known high-yielding characteristics of varieties, sweet cherry varieties grafted onto standard rootstocks with a proportion of 2-4 flowers per flower bud exceeding 65% were classified as high-yielding varieties.

[0041] Example 2

[0042] In late August 2015, Gisela 6 dwarfing rootstock was prepared through softwood cuttings, using the same method as the Gisela 6 rootstock cutting propagation mentioned above. In early September 2016, eleven varieties (lines) were grafted onto Gisela 6 rootstock using xylem budding: 'Shamidou', 'Hongdeng', 'Meizao', '219' (Changhua Zixia), '793' (Wanmilu), 'Dong8bei17', 'Dong6bei29', 'Dong6nan11', 'Dong8bei1', 'Dong6bei26', and 'Dong6nan5'. These were pruned to create a slender spindle-shaped tree and managed with standard water, fertilizer, and flower / fruit care. In 2021, flower bud parameters were measured on the varieties (lines) with different rootstock-scion combinations that had been planted for four years. The specific measurement method is as follows: during the inflorescence separation period of each variety, the number of flower buds in each of 100 flower buds is randomly measured, and the proportion of different flower bud numbers in each flower bud is counted. The measurement results are shown in Table 2.

[0043] Table 2. Percentage of flowers per flower bud in varieties grafted onto Gisela 6 rootstock

[0044]

[0045] As shown in Table 2, among the 12 varieties (lines) grafted onto the dwarfing rootstock Gisela 6 evaluated, 'Shamidou', 'Hongdeng', 'Changhua Zixia', and 'Wanmilu' were high-yielding varieties, with 97%, 89%, 83%, and 96% of each flower bud containing 2-4 flowers, respectively; 'Meizao' was a lower-yielding variety, with 67% of each flower bud containing 2-4 flowers. Based on the known high-yielding characteristics of varieties, sweet cherry varieties grafted onto dwarfing rootstocks with a proportion of 2-4 flowers per flower bud exceeding 80% are considered high-yielding varieties.

[0046] Example 3

[0047] Based on the schemes provided in Examples 1 and 2, under the same pruning and management modes: sweet cherry germplasm grafted onto the standard rootstock Benxi Prunus serrulata has a higher proportion of 2-4 flowers per flower bud than 65%, and is judged as a high-yielding variety; sweet cherry germplasm grafted onto the dwarf rootstock Gisela 6 has a higher proportion of 2-4 flowers per flower bud than 80%, and is judged as a high-yielding variety. According to this standard, the high-yielding varieties (lines) are 'Shamidou', 'Hongdeng', '219' (Changhua Zixia), '793' (Wanmilu), 'Dong8bei17', 'Dong6bei29', 'Dong6nan11', and 'Dong8bei1', while the non-high-yielding varieties (lines) are 'Meizao', 'Dong6bei26', and 'Dong6nan5'.

[0048] To verify the feasibility of the screening method of the present invention, in 2023, the yield of 11 varieties (lines) grafted on two rootstocks and planted for 6 years was measured. Three plants were selected for each rootstock-scion combination, and their average value was measured. The results are shown in Table 3.

[0049] Table 3. Yields of 6-year-old trees grafted onto two types of rootstocks

[0050]

[0051] The yield measurement comparison verified the feasibility of the screening methods provided in Example 1 and Example 2. That is, the proportion of sweet cherry varieties (lines) grafted onto the standard rootstock Benxi Mountain Cherry with 2 to 4 flowers per flower bud exceeds 65%, and the proportion of sweet cherry varieties grafted onto the dwarf rootstock Gisela 6 with 2 to 4 flowers per flower bud exceeds 80%, which can be identified as high-yielding varieties.

[0052] In summary, this invention provides a method for evaluating high-yielding sweet cherries. This method is simple, effective, and has a short cycle, which can shorten the breeding cycle for screening high-yielding varieties.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the yield potential of sweet cherries, characterized in that, The sweet cherry scions to be evaluated were grafted onto the rootstock. When the scions developed to the inflorescence separation stage, the proportion of flower buds with 2-4 flowers in the total number of flower buds was counted. Based on the proportion, it was determined whether the sweet cherry to be evaluated was a high-yielding type. The rootstocks include standard rootstocks and dwarf rootstocks; the criteria for judgment include: the proportion of flower buds with 2-4 flowers grafted onto standard rootstocks is ≥65% of the total number of flower buds, and the proportion of flower buds with 2-4 flowers grafted onto dwarf rootstocks is ≥80% of the total number of flower buds, then the sweet cherry to be evaluated is judged to be high-yielding.

2. The method for evaluating the yield potential of sweet cherries according to claim 1, characterized in that, The standard rootstock is Benxi cherry rootstock; and / or, the dwarf rootstock is Gisela 6.

3. The method for evaluating the yield potential of sweet cherries according to claim 1, characterized in that, Grafting should be performed when the rootstock seedlings grow to 0.6-1cm.

4. The method for evaluating the yield potential of sweet cherries according to claim 1, characterized in that, Use scions from fertile branches.

5. The method for evaluating the yield potential of sweet cherries according to claim 1, characterized in that, Grafting is performed using xylem budding.

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