Recent Techniques and Developments on Cherry Growing in Turkey

Abstract

The wild cherries are mostly seen in the North Anatolian and the Taurus mountains of Turkey. Cherry cultivation is concentrated on the slopes of 1000–1500 m where wild cherries are grown, also at the river valleys or in Izmir and Manisa provinces at the western parts of the country over 100 m elevation with very high quality. Turkey is the leading country in the world on cherry production. Cherry production in Turkey has been performed mostly with ‘0900 Ziraat’ cherry cultivar, which was known as Turkish cherry in Europe. As a result of the studies carried out for fruit cracking and self fertility, Regina, Kordia, Sweet Heart and Lapins cherry cultivars were selected as alternative cherry cultivars to ‘0900 Ziraat’. In 1997, “Turkish National Cherry Working Group” was founded and organized 20 working group meetings until today to solve all the problems of cherries. In these meetings, all the research results were shared and discussed among cherry scientists. Recently, studies on prolonging the cherry season with early and late cherry cultivars to increase the amount of cherry exportation was achieved. For this aim, Sweet Heart at high elevations, Royal Lynn® and Royal Tioga® at subtropical climatic conditions were found to be suitable.

1. Introduction

The origin of the cherry (Prunus avium L.) is in the southern Caucasus, the Caspian Sea and north-eastern Anatolia. Cherry has spread from the center to the east and west and has covered a wide area in the world. Considering cherry germplasm in the world, the wild forms of cherry are grown in the northern Anatolian mountains and at the Taurus mountains of the South Anatolia in Turkey [1].

Cherries grow large trees up to 15 m in height upright and scattered, the branches are smooth, the growth tips are sticky when the leaves open. The flowers form white double or triple bunches. The fruits are in different shapes and colors and the core is semiadherent to the flesh. The fruit is colorless in some cultivars and very dark red in some cultivars [1, 2].

Cultivation of cherry is naturally and wildly grown on the slopes and river valleys of the North Anatolian Mountains, Western and Central Taurus Mountains and at the 1000–1500 m elevations of the Mediterranean side of Eastern Taurus Mountains with very good quality cherries. However, rainfall during the flowering period negatively affects fertilization by preventing bee flight. Also, excessive and long-lasting rainfall at harvest time of ‘0900 Ziraat’ cherry cultivar causes cracking and decreases the cherry production. For this purpose, cracking resistant cultivars have been introduced with TÜBİTAK (The Scientific and Technological Research Council of Turkey) and DPT (State Planning Organization) supported projects which were carried out at the Pozantı Agricultural Research and Application Center of the University of Çukurova. As a result of these experiments, ‘Regina’ and ‘Kordia’ cherry cultivars were determined to be resistant to cracking, and grown and exported besides ‘0900 Ziraat’ national cultivar and ‘Sweetheart’ and ‘Lapins’ self fertile cultivars.

“Turkey’s National Sweet Cherry-Sour Cherry Working Group” was founded in 1997, under the leadership of Prof. Dr. Dr. Nurettin Kaska. Later on, T.C. The General Directorate of Agricultural Research and Policies (TAGEM) of the Ministry of Agriculture and Forestry undertook this organization. All the problems and solutions related to national cherry production were discussed in these working group meetings held 22 times so far and shared with the stakeholders.

1.1 Cherry production and export

Cherry production of Turkey has increased to 732.000 tons in 2020 from 215.000 tons in 1997. Turkey usually exceeded the estimates of the cherry marketers. However, considering the exportation, Turkey ranks third or fourth and most of the exportation has been traditionally performed to Russia and the European Union. Fruit prices in the world cherry market rise to the highest levels both in the early season in April and late season in August. Among world cherry producer countries, USA, Chile and Turkey take the first three places in exportation. Turkey’s cherry exportation in 2020 was 87.944 tons and ranked 4th in cherry exports. This is because Austria and Hong Kong (China) play an important role in the cherry trade, although they do not have a say in cherry production. Although cherry ranks 4th, it is the most valuable crop in our exports in terms of income.

2. Cherry cultivar adaptation studies

The first trial in Turkey on cherry cultivar adaptation experiments was carried out in Yalova Atatürk Horticultural Central Research Institute on “Selection of local and foreign sweet cherry and sour cherry cultivars” by Dr. Fahrettin Oz. In this study, 51 sweet cherries, 7 sour cherries and 1 sweet cherry-sour cherry hybrid of domestic and foreign cultivars were selected in 1974 and 1975 for their fruit quality characteristics. Yalova Horticultural Central Research Institute carried out cherry adaptation trials in different parts of Turkey from 1982. With these studies ‘0900 Ziraat’ major sweet cherry cultivar and pollinators (‘Lambert’, ‘Bigarreau Gaucher’ and ‘Starks Gold’) became popular.

S alleles of ‘0900 Ziraat’cultivar are S3/S12. Another German cherry cultivar with the same S allele is Nordwunder (Schneiders Späte Knorpel), ‘Princess’ (Prinzesskirsche) and in Italian cherry cultivar ‘Ferrovia’. Therefore, there are various opinions that these two cultivars are the same. The cherry cultivar ‘Schneiders Späte Knorpel’ was discovered in 1850 in Guben, Germany, by co-producer Schneider. Today, it is still one of the most produced cherry cultivars in Germany. Another cherry cultivar found in Guben is ‘Noir de Guben’. This cultivar is produced in our country under the names of ‘Kemalpaşa Napoleon’ in Kemalpaşa, ‘Erkenci Napoleon’ in Bursa and ‘0900 Ziraat’ was also grown under the name of ‘Napoleon’ [3, 4, 5, 6].

Although ‘0900 Ziraat’ national sweet cherry cultivar has a high fruit quality such as resistance for transportation, long shelf life, good fruit flesh firmness, very good taste and aroma, it has also some inadequate features such as low yield caused by the rainfall during the pollination period. Many studies on these problems and similar issues on cherries have been carried out in the Faculty of Agriculture of the University of Cukurova. These studies include; adaptation of cherry cultivars to subtropical conditions [7, 8]; ‘Aksehir Napolyonu’ cherry cultivar packaging and storage in a modified atmosphere, developments on pre-cooling and cold transportation of cherries [9]; clonal micro propagation of clonal cherry rootstocks, investigations on new cherry cultivars adaptable to cold regions of our country, classification of cherry (Prunus avium L.) and sour cherry (Prunus cerasus L.) cultivars by DNA fingerprinting method [10, 11].

Another project was carried out during 1995–1996 by Dr. Nurettin Kaska and his colleagues at Ulukışla and Pozantı villages to increase the economic levels of export-oriented cherry growing potential by modern methods’. With this project, the first pruning was applied on cherry trees.

Newly introduced foreign and local cherry cultivars were used in this project such as Regina’, ‘Venüs’, ‘Summit’, ‘Lapins’, ‘Na-478′, ‘Na-474′, ‘Noir de Guben’, ‘Van’, ‘Larian’, ‘Akşehir Napoleon’, ‘Starks Gold’, ‘Octavia’, ‘Bigarreau Gaucher’, ‘0900 Ziraat’, ‘New Star’, ‘Durono-3′, ‘Tardie de Vignola’, ‘Na-1(Nafrina)’, ‘Early Burlat’, ‘Van Compact’, ‘Bing Spur’, ‘Sunburst’, ‘Fercer Arciana’, ‘Meckenheimer’, ‘Hedelfingen’, ‘Nadino’, ‘E. Rivers’, ‘Kordia’, ‘Precoce de Bernard’, ‘Garnet’, ‘Telegal’, ‘Cristobalina’, ‘Namosa’, ‘Lamida’, ‘New Star’, ‘Prima Giant’, ‘Rainier’, ‘Early Lory’, ‘Big Lory’, ‘Late Lory’, ‘Sweet Heart’, ‘Ferrovia’, ‘Tieton’ and ‘Staccato’ [12].

Orchards were established with these sweet cherry cultivars at different institutes and locations such as Uludağ University Faculty of Agriculture, Yalova Atatürk Horticultural Central Research Institute, Eğirdir Horticultural Research Institute, Malatya Apricot Research Institute, Ordu University Faculty of Agriculture, Çukurova University Faculty of Agriculture and Pozantı Agricultural Research and Application Center. As the result of these studies, ‘Regina’ and ‘Kordia’ cherry cultivars were found to be the best quality cherries in the country [13]. New cultivars were added to those sweet cherry cultivars in Yalova and Eğirdir in 1999 which were ‘Precoce de Bernard’, ‘Techlovan’, ‘Sylvia’, ‘Summit’, ‘N. de Meched’, ‘0900 Ziraat’, ‘Octavia’, ‘Belge’, ‘Sweetheart’, and ‘Regina’. The best results were obtained from ‘Veysel’, ‘Noir de Meched’, ‘Ranier’, ‘0900 Ziraat’, ‘Octavia’, ‘Belge’, ‘Lapins’ ‘0900 Ziraat’ and ‘Sweetheart’ cherry cultivars in Eğirdir and Yalova ecological conditions considering the harvesting time [13].

In a study carried out by Bas et al. [14] on determination of self fertile and exportable cherry cultivars by cross breeding and mutation methods, ‘0900 Ziraat’ and self-fertile ‘Stella’ and ‘Sweetheart’ cultivars were used as parents. Ten of them were taken to the second stage of the selection. Cherry breeding studies have been continued in Yalova and Eğirdir research institutes.

As a result of the experiments carried out at Çukurova University on cherry adaptation in early ripening cherries, these cherry cultivars were detected (end of April-May) ‘Cristobalina’ (self fertile), ‘Prime Giant’ (Pollinators; ‘Brooks’, ‘Lapins’), for mid season cherries, ‘Lapins’ (self fertile), ‘Regina’ (Pollinators; ‘Skeena’ and ‘Durone 3 Nero’ and ‘Kordia’ (Pollinators; ‘Summit’, ‘Skeena’ and ‘Regina for late ripening cherries ‘Sweet Heart’ (self fertile) cherry cultivars were found. ‘Regina’ and ‘Kordia’, resistant cultivars to fruit cracking and ‘Sweetheart’, late season cultivar were found to be suitable for exportation. The very early cherry cultivar ‘Cristobalina’ was found to be more suitable for the domestic market.

3. Morphological and biological characteristics of cherries

Cherry trees usually form a pyramid-shaped crown that rises up to 20–25 m. The trunk of the trees is upright and smooth, and the trunk is grayish-black or dull black with transverse stripes. Cherry branches are smooth, internodes are long in standard cultivars. Flower buds generally begin to form bouquet flowers at the bottom of the branches in the 2nd year. The buds form two types of buds as wooden buds and fruit buds. Wooden buds are thinner and smaller than fruit buds. Fruit buds are large and plump, and they are found in the twigs as side buds. In bouquet branches, there is a shoot bud in the middle and 5–6 fruit buds around it. In fruit buds, the flowers are not one by one, but many. The number of flowers also increases up to 6. The flowers have 5 sepals and 5 petals and up to 30 stamens. Flowers normally have one pistil. Some cultivars have double pistils. The formation of multiple pistils is related to climatic conditions as well as a kind of feature. During flower bud formation in summer, high air temperatures increase the number of double pistil flowers. Multiple pistil flowers reduce the market value of the fruits as they cause twin fruit formation [15].

4. Fertilization biology of cherries

In terms of fertilization biology of cherries, self incompatibility and cross incompatibility may occur so this situation should be taken into account in orchard plantations [16, 17]. Most of the local cherry cultivars grown in the Marmara Region were found to be self incompatible. Thus, ‘Starks Gold’, ‘Bigarreau Gaucher’, Merton Late’ and ‘Lambert’ cultivars are recommended as pollinators for our important export cultivar ‘0900 Ziraat’. The reason for the low yield of ‘0900 Ziraat’ sweet cherry cultivar was found to be the unfavorable weather conditions during the pollination and fertilization period [18]. As a result of these studies in 2017, the pollinators for ‘0900 Ziraat’ were determined and given in Table 1. According to the results, the best pollination in ‘0900 Ziraat’ cherry cultivar was obtained with ‘Merton Late’. However, Stark’s Gold, Lambert and Bigarreau Gaucher could only pollinate ‘0900 Ziraat’ 50% even if the flowering times coincide. In this case, the reason for the low yield of ‘0900 Ziraat’ in 2017 was the use of ‘Stark’s Gold’ cherry cultivar in most of the cherry orchards which have only 50% of pollination ability (Figure 1 and Table 1). When the unsuitable weather conditions were also considered, the yield was very low.

1. Self incompatible

2. 50% pollination

3. 100% pollination

Pollinators	S allelles	Pollination rates (%)
Starks Gold	S3S6	50
Bigarreau Gaucher	S3S5	50
Merton Late	S1S4	100
Lambert	S3S4	50

Table 1.

The pollinators and the pollination rates of ‘0900 Ziraat’ (S3-S12).

Figure 1.

The pollination ability of similar and different alleles. a. Sterile. b. 50% pollen sterile. c. 100% pollen fertile.

Many nurseries recommend ‘0900 Ziraat’, ‘Regina’, ‘Sweet Heart’ and ‘Kordia’ cherry cultivars to establish cherry orchards. Self fertility, flowering periods and pollination ability of cherry cultivars in nurseries and in orchard plantations should be taken into account (Table 2).

Cultivars	Flowering periods	S alleles
Prime Giant	Mid early	S1S9
‘Lapins’	Early	S1S4 (Self-fertile)
‘Brooks’	Mid early	S1S9
‘Burlat’	Mid early	S3S9
‘Regina’	Late	S1S3
‘Kordia’	Mid late	S3S6
‘Sweetheart’	Mid late-late	S3S4 (Self-fertile)
‘Rainier’	Early	S1S4
‘0900 Ziraat’	Mid season	S3S12
‘Ferrovia’	Mid season	S3S12
‘Staccato’	Mid season	S3S4 (Self-fertile)

Table 2.

Flowering periods and S-alleles of some important cherry cultivars.

On the other hand, cherry orchards are also established with self fertile cultivars. In this case, although the cultivars are self fertile, bee activity and little windy weather are needed in the orchards for a better pollination at the flowering period. There is no bee activity at temperatures below 10°C and above 38°C. Generally, bee flights are very low at temperatures below 12–14°C. Also, in heavy windy, rainy and cloudy weather bee flight is very weak. For this reason, wild bees are used for fertilization in cold and rainy climates. For this purpose, bee hotels are made or bunches of reeds at different diameters hang on the row of cherry trees.

Thousands of wild bees can fly in unsuitable weather conditions where honey bees can not fly and provide fertilization. Each alone female makes her own nest and finds food for herself and her offspring. Ninety percent of wild bee species live alone. Seventy percent of the 20,000 bee species in the world live underground. Therefore, to keep the bee nests intact, covered soil tillage is becoming forward in cherry orchards.

5. Sweet cherry cultivars

Early Burlat (S3S9); Early Burlat ripens in the early season. It is firmer than Black Tartarian, softer than Bing and known for its consistent productivity of medium-sized, Bing-like cherries. Early Burlat is resistant to bacterial canker and cracking. The tree is moderately vigorous and spreading. Early Burlat pollinated by Rainier.

Merchant (S2S4); Origin - United Kingdom; fruit size medium (fairly large for season); good quality fruit; hangs well on tree; picks with dry stem scar; cracks quite badly; vigorous, health tree. Comments: Worthy of trial as early fresh market cherry, but cracking may be too severe. It is a universal pollen donor, blossoms mid-season, and is one of the earlier cultivars to mature. Pollinated by Burlat, Stella, Lapins, Sunburst. Pick time early July. Merchant is early mid season cultivar with very large, black fruits. Very heavy cropping.

Tieton (S3S9); Very large fruit (10–14 g) with mild flavor and export quality firmness. Dark red skin. Very early harvest. Gisela rootstocks are suggested to increase cropping potential. Tieton™ is an early-ripening mildly sweet cherry with a beautiful, glossy mahogany red finish over medium red flesh. The fruit is very large with excellent firmness and a susceptibility to rain cracking similar to Bing. To encourage productivity, Tieton™ should be planted with more than one cultivar of pollinizer and/or more than 10% pollenizer density. Pollination Rainier, Bing, Van, Lapins and Sweetheart™; use of multiple pollinizers recommended.

Brooks (S1S9); Developed by the University of California, Brooks is a large, firm red cherry that tolerates hot climates. This cultivar is very susceptible to cracking in rain. Brooks, ripens 10–14 days ahead of Bing. A very large fruit that is firm with an exceptional flavor. There are very few doubles in the fruit set in hotter climates. It is susceptible to severe cracking in the rain. Pollinators for Brooks are Bing, Rainer, Early Burlat and Tulare.

Prime Giant (S1S3); This cherry ripens with Brooks about 7–10 days after Burlat. It is very firm and large and has an excellent, sweet-tart taste. Seven days before harvest this cherry had a much stronger and better flavor than a ripe Burlat. Sugars and flavor are produced early, before the cherry is ripe. Marvin Niece in California developed prime Giant. I thought this was a good cherry but I have two major concerns about this cherry. First, it is susceptible to rain cracking, and second, trees in Europe had a virus that was killing the trees. It needs to be cleaned up before it is of interest, but otherwise a great-looking cherry. The trees are a very fertile cultivar that thrives in the mid trough. Even though it is early, the fruit is 10–11 g. Heavily weighted, heart shaped. The outer diameter of the stem is middle length fruit is bright red color. Flesh is pinkish, juicy and aromatic. It is susceptible to cracking. The harvest time is at the end of May, 10 days after Early Burlat.

Lapins (S1S4); Very large fruit is the hallmark of the Lapins cherry. Lapins cherries are firm and crack-resistant with a mahogany-red skin and lighter red flesh. Self-fruitful, Lapins ripens 10–14 days after Bing in the Northwest and 5–7 days after Bing in the Central Valley of California. Lapins is crack resistant, similar to Van in color and resembles Stella in shape. The estimated chilling requirement 500 hours.

Rainier (S1S4); The Rainier title has become well established as a promise of unmatched flavor. Rainier is a large, yellow cherry with a red blush and light yellow flesh. Exquisitely flavored with high sugar levels, this is a premium niche cultivar that ripens just after Bing. The tree is vigorous, early bearing and very productive with excellent cold weather hardiness. Rainier requires cross-pollination and is inter fruitful with Sweetheart and Lapins. Pollinators for Rainier Lapins, Sweetheart, Early Burlat. Estimated chilling requirement is 700 hours. In addition, Rainier is highly susceptible to powdery mildew and rain cracking.

Attika (Kordia) (S3S6); A Czeck raised cultivar. In Europe, Skeena and Regina® is a good pollinator for Kordia. Kordia is a mid season sweet cherry producing a heavy yield of large, firm, black fruit with a good flavor. It has some resistance to cracking, is not self fertile, and is ready to pick in mid summer.

Regina (S1S3); Good quality (13 g), highly crack resistant. It was developed in an area with high bacterial canker pressure, so should have good bacterial canker tolerance. Very large cartilage cherry, solid, reddish brown, sweet, rich. Regina is a high quality, late season cherry that exhibits excellent rain crack resistance. The fruit is very large and firm, with a mild, pleasant flavor. When ripe, this cherry is darker than most. For peak flavor, it is important to delay harvest until total soluble solids reach 20–22%. In order to ensure high quality yields, a regular cut in autumn or early spring, mandatory! In this context and due to different educational forms, the final height can be determined by fruit trees, depending on the amount of space required. Large shrub or small tree, taut-broad erect, pyramidal crown, loosely branched, 3–5 m high and 2–4 m wide. Pollinators for Regina, Sweetheart and Attika-Kordia.

Sweet Heart (S3S4); Sweetheart™ is a large, bright red heart-shaped cherry. Sweetheart™ matures at the end of the season, about 5–7 days after Lapins and remains firm after picking. This self-fruitful cross of Van and Newstar is productive with good firmness, size and flavor. The tree is spreading and precocious, yielding heavy crops on all rootstocks. Sweetheart™ shows moderate cracking. Very late productive, medium to large fruit, very good firmness and good flavor. Tree survival was reported poor from northern Germany where bacterial canker is a serious problem. As with Lapins, trial plantings should only be made on excellent sites, but may have a niche for late season local sales (though cracking is a problem).

0900 Ziraat; It is the most cultivated cultivar of Anatolian origin known as Salihli, Akşehir Napoleon, Uluborlu and Dalbastı, and this cultivar supplies the 90% of our exports. 0900 Ziraat cherry is in demand from the foreign markets due to its fruit size and other quality features. The trees grow very vigorously, semi upright and form a wide crown. It is incompatible with itself. Its fruits are large (8-9 g), dark bright red, hard, crispy, long stemmed. Fruit flesh is juicy, very resistant to cracking and transportation. Ripening is in the last week of June. Fertilizers, Lambert, Starks Gold, Regina, B. Gaucher, Lapins, Metron Late. Noble varieties.

0900 Ziraat cultivar S alleles are S3/S12. Another cultivar with the same S alleles is the German cherry cultivar Nordwunder (‘Schneiders Späte Knorpel). Therefore, there are various opinions that these two cultivars are the same. The cherry cultivar ‘Schneiders Späte Knorpel’ was found by the producer Schneider on the banks of the Neisse River in Guben, Germany, as a random seed in 1850. This cultivar was recommended and planted everywhere from the early 19th century until the 1960s as the queen of cherries sprung from Guben city, the cherry growing center in Germany. Today, it is still one of the most produced cherry cultivars in Germany. Other cultivars with the same S alleles (S3/S12) are Ferrovia grown in Italy and Princess (Prinzesskirsche) in Germany.

6. Ecological requirements of cherries

In our country, cherries grow naturally between Artvin and Kocaeli in North Anatolia and Taurus Mountains in the south. Culture cherries are also concentrated on the slopes and river valleys of these mountains at an altitude of 1000–1500 m. However, in recent years, with appropriate rootstock and cultivar selection, the growing areas have spread to lower regions such as Bursa, Iznik, Çanakkale, Izmir (Kemal Paşa) and Manisa in the Aegean region.

Cherry is a high chilling requiring species. The chilling requirements of the cherry cultivars grown in our country are between 500 and 1500 h. Winter cooling is necessary to break dormancy and continue the development in spring. If this requirement is not satisfied, irregular flowering and flower drops are seen. In this regard, approximately 1000 m altitudes are ideal regions for cherries. Cherry trees can damage at low temperatures below −20 and − 24°C. One of the most important factors limiting cherry cultivation is late spring frosts. The flower buds usually die at −4°C, although it also depends on some other factors. Opened flowers are damaged at −2°C. Extreme summer temperatures are undesirable because it promotes double pistil formation and twin fruits and such fruits have no market value.

7. Cherry growing techniques, orchard management

Cherries are propagated by budding and grafting on several rootstocks. In Turkey, cherries and sour cherries are generally propagated by dormant budding. Although, this budding period varies according to the climatic conditions, it is mostly carried out between July and September, usually by classical “T” budding method.

In subtropical climatic conditions with a long vegetation period, the most suitable budding period is the spring budding period in February-March. Budsticks can be taken directly from the trees for chip budding. There are negative points for classical “T” budding at spring growth season in April. First of all, it is necessary to wait for the removal of the bark of the rootstocks and the budsticks have to be kept at low temperatures until mid-April for the most suitable period for budding. In April buddings, the bud union may be delayed, the growth season shortens and the seedling quality may decrease. For this reason, the most suitable propagation period for cherries and sour cherries is in winter with chip budding under controlled or outdoor budding conditions.

The natural growth habit of cherry trees is upright and vigorous, forms very high trees. The formation of large trees also affects the planting distances and the cherry orchards are planted at intervals of 7 × 7–8 × 8 m, even 10 × 10 m. The height of them should be reduced by using dwarf rootstocks. Recently, dwarf rootstocks, spur and compact cultivars have been used in modern fruit growing. In traditional cherry cultivation in our country, medium strong P. mahalep in calcareous soils and very strong P. avium rootstocks are used in low calcareous soils.

Today, cherry production in many European countries is declining in favor of pome fruits. The reasons for this are; very high forms of the trees, difficulty in mechanization, high labor costs in harvest and in other cultural techniques. Tree heights can be kept at 3.5–4 m by using dwarf rootstocks with low crown. Planting intervals can be reduced from 9 × 7 or 8 × 6 m to 5 × 5, 5 × 2.5 and 4 × 1.6 m.

8. Cherry rootstocks

Belgium: Three commonly used rootstocks; Inmil (G.M.9), Damil (G.M.61) and Camil (G.M.79). Germany: 12 rootstocks under the name of Gisela were obtained during the hybridization studies of cherry rootstocks in Giessen. Apart from Germany, these rootstocks have started to spread in Europe and America. 5 sour cherry selection was obtained from the rootstock in M. Freising Weihestephan University. These are W-10, W-13, W-53, W-72 and Weiroot 158. In the hybrid studies conducted by H. Fisher at the Pillnitz Research Institute in Dresden, PiKu 422 and Pi-Ku 483 rootstocks were obtained. Italy: CAP rootstocks were obtained by selection from cherries at the University of Bologna. USA: MM series or MaxMa rootstocks were obtained from P. avium and Prunus mahaleb hybrid studies. These; MxM2, MxMI4, MxM34, MxM60 and MxM97. Czech Republic: PHLA and PHLB rootstocks were obtained by sour cherry selection. Spain: MM9, MMP12 rootstocks by selection from sour cherries and Adora rootstock were obtained by selection from plums. France: Mahaleb SL-64 rootstock selection and Tabel Edabriz selection were obtained from sour cherry. Among these rootstocks, mostly MaxMa is used in our country (Table 3).

Tree form	Rootstocks	Planting distances (m)	Tree per/ha
Spindel	Maxma14	4.5 × 3.5	593
Spindel	Gisela 6	4.5 × 2.5	831
Drapeau	Maxma14	4.5 × 3.5	593
Drapeau	Gisela 6	4.5 × 2.5	831
Bush	Maxma14	5 × 3.5	534
Bush	Gisela 6	5 × 2.5	748
Mikado	Maxma14	5 × 2.5	748 (4 main branches)
Drilling	Gisela 6	5 × 2	935 (4 main branches)

Table 3.

Different training, planting distances and number of trees per hectare in Turkey.

Another problem in cherry seedling production is the inoculation of cultivars suitable for rootstocks. This problem was encountered on Giesela rootstocks. In the orchards established with self fertile Sweetheart and Lapins cherry cultivars on dwarf Giesela-5, the fruit size did not reach the export size due to excessive fruit set.

9. Pruning of cherry trees

No pruning was applied on cherry trees before 1996 in Turkey except cutting dry branches. In a cherry meeting with cherry growers and technicians in Pozanti Agricultural Research and Application Center, under the leadership of Prof. Dr. Nurettin Kaşka in 1996, Prof. Dr. Ali Küden [19] gave a seminar and a training course on pruning and showed pruning applications on cherry trees at the orchard conditions at the first time in the country. After this activity, several pruning seminars and applications were held in cherry regions, such as training of 30 Agricultural Engineers from various institutes of the Ministry of Agriculture in Pozanti Center. In this way, new cherry cultivars and new pruning methods of cherries were spread in important cherry production regions.

The experimental cherry trees established at Pozantı Agricultural Research and Application Center were given a different upright branching shape and pruning was done in the following years. As in other fruits, pruning in cherries can be divided into three groups which were: training, yield pruning and rejuvenation pruning. Generally, the training shapes given to cherry trees were; Modified Leader, Spindel, Super Spindel, Super Spindel Ax, Solax, V system, bush, KGB, Spanish bush system, Fan, Upright Fruiting Offshoots (UFO), Drapeau and Bibaum. Recently, the Super Spindel Ax and UFO in USA, the Fruit Wall system in France and the 3-branch Fruit Wall system in Italy are getting popular.

These pruning forms have been developed in different countries by considering their soil and climatic conditions such as humidity, lightening and common cherry diseases and economical causes. In Belgium, compared the classical system, the British system, the Spanish bush system, the V-system and the UFO-systems in the European project on ‘Kordia’ and ‘Sweetheart’ cherry cultivars grafted on Gisela-5 rootstock. At the end of this study, the classical system was found to be the best in terms of efficiency and quality [20].

According to the rootstocks, pruning and planting systems were changed in cherries, for early fruit set, dwarf rootstocks came forward. In another study carried out at Çukurova University to get early fruit set from the cherries grafted on semi-dwarf and strong rootstocks, short cuts in winter pruning (Figure 2) and shoot breaking method.

Figure 2.

In winter pruning, with short cuts of 5-15 cm in annual shoots fruit set in the same summer and the second summer fruit production.

9.1 Short cuts

In a study carried out in Ulukışla, short cuts of 5–10–15 cm in winter were applied to 1–2 years old branches of ‘Lapins’, ‘Summit’, ‘Sweetheart’ and ‘0900 Ziraat’ cultivars grafted on Purunus. mahaleb rootstock and the amount of carbohydrate in the cut branches was higher than the uncut branches [21].

Nitrogen contents of the branches were found to be higher in the uncut branches and lower in the cut branches. On the cut shoots, fruit bouquet, called the 1st summer may bouquet, was formed, and immediately the second summer fruit was taken. In this case, the branches should be cut and discarded in the shape of the pruning and short cuts caused early fruit set. At the end of this research, short cutting was accepted to be a good method to break juvenility period [21].

The shoot tips of cherries get too much nitrogen. When the shoots are cut, nitrogen uptake decreases and carbohydrate (Ch) accumulation increases (Table 4). According to these results, in winter pruning, 1–2 years old shoots are cut from 40 to 50 cm in standard cultivars and from 25 to 30 cm in self-fertile cultivars. As a result of this study, shortening the juvenility period of the young cherry trees by shoot cutting was determined to be possible (Figure 3).

Cultivars	Control (no pruning)			5 cm cut			10 cm cut			15 cm cut
	Fruit bud	CH (%)	N (%)	Fruit bud	CH (%)	N (%)	Fruit bud	CH (%)	N (%)	Fuit bud	CH (%)	N (%)
Sweet Heart	—	9.3	0.86	3	9.6	0.53	4	10.7	0.75	5	16.7	0.80
Lapins	—	5.0	0.82	8	11.5	0.43	2	11.1	0.68	6	6.3	0.52
Summit	—	8.1	1.07	7	9.0	0.69	6	4.9	0.71	5	14.5	0.75
0900 Ziraat	—	3.2	0.85	10	6.9	0.48	11	6.5	0.37	8	14.4	0.52

Table 4.

The effect of different short cuttings of the shoots on the nitrogen and carbohydrate accumulation.

Figure 3.

In winter pruning, with short cuts of 20–25 cm in annual shoots fruit set in the same summer and the second summer fruit production.

9.2 Breaking shoots

Dwarf rootstocks in cherries as well as expanding branch angles, hanging various weights and semi horizontal planting accelerates the formation of fruit buds. However, the branch breaking method previously applied in apples, also gives very positive results in cherries (Figure 3).

In the branch breaking method, ¼ of the branches are cut from the top and the branches are half broken. As a result, fruit buds are formed in the broken branches in 1–2 years (Figures 4 and 5).

Figure 4.

Tying the broken branches after winter pruning, formation of flower buds, flowering and fruit set.

Figure 5.

Tying the broken branches, this application is done in February – March.

In cherry trees, 40–60 cm cuts are made in the whole crown according to the development of the shoots from outside to inside. In cherry trees, especially the injured and cut areas are the entry points of the bacteria that cause branch cancer, cutting thick branches in winter pruning increases the risk of branch cancer in the trees.

Bacteria, which are branch cancer agents and cause gluing at these points, are rarely found in nature, especially in August. For this reason, shape prunings should be done in early July, and thick branches in yield prunings should be done in August. In winter pruning, the thickness of the cut branches should not exceed finger thickness. Thicker branches should be made at 15–20 cm lengths in thick branch sections in areas where the disease is very common. As a result, the pruning of cherry trees should be done in winter and July, while in winter prunings yield pruning in thin branches and short cuts should be done in these branches, especially in areas where branch cancer is common, thick branch segments should be left to the end of summer.

• Standard tree pruning (mature tree) 40–60 cm

• Spur and selfertil cultivars 20–30 cm

• Bush tree 5–15 cm

• Apical Pruning: Nitrogen uptake stops when branches are cut, carbohydrate is accumulated.

10. Cherry growing under subtropical climatic conditions with low chilling cultivars

Generally, sweet cherries in Turkey are midseason cherries and grown in June and July. To extend the growing season of cherries and widen the exportation period, cherries were begun to be produced at the subtropical region of Turkey at the Mediterranean coastal line, since the prices at early and late season cherries are very high.

Under subtropical climatic conditions, cherry cultivation experiments started in 1990 with a self-fertile cultivar Stella. The main problem in cherries in this area was not only the insufficient chilling, but also the fertilization problems. The studies began on apple and pear in 1984, and on cherries in 1990 [6]. For this purpose, cherry collection orchards were established in Adana. In the meantime, the chilling requirements of the cultivars and the chilling duration of the area were determined.

Küden et al. [7], determined the performances and the chilling requirements of ‘Stella’, ‘Noir de Guben’, ‘Van’ and ‘Bing’ cherry cultivars and ‘Kütahya’ sour cherry cultivar under subtropical conditions with the classical and chill unit methods. In the study, the chilling requirements were determined as 600–1200 h for ‘Stella’, 700–800 h for ‘Noir de Guben’ and 1000–1200 h for ‘Van’. Considering these results, it was reported that ‘Stella’ and ‘Noir de Guben’ cherry cultivars can be grown under subtropical conditions with some cultural practices. KNO₃, thiourea and hydrogen cyanamide (Dormex) were applied to break the dormancy of the buds in cherry cultivars. Among chemical applications, KNO₃ + thiourea (2% + 1%) combination gave the best results. The bud broke dormancy 100%, 96%, 92% and 77% respectively on ‘Stella’, ‘Van’, ‘Noir de Guben’ and ‘Bing’.

Küden and Küden [22], stated that ‘Cristobalina’, “Temprano de Sot’, ‘Precoce de Bernard’, ‘Sunburst’, ‘Lapins’, ‘Chelan’ and’ ‘Na-1’were found to be the promising cultivars and adaptable to subtropical climatic conditions.

Imrak et al. [15] studied on ‘Na-1’, ‘Early Van Compact’, ‘Bing Spur’, ‘Lapins’ and ‘Cristobalina’ cherry cultivars under subtropical conditions to prevent or decrease the multiple fruit formation that occurred at the differentiation period of the buds over 30°C. They found the use of green net with a shading feature of 55% used as a cover system to reduce the air temperature values between 1.9°C and 3.1°C and reduced double pistil formation ranging from 60.87% to 27.81% percentages.

Another issue in warm regions is that the cover materials used in cherry orchards are not collected during the winter. In this way, the trees are kept in a cooler environment with the shade effect on sunny days and help to satisfy chilling.

The studies on cherry growing under subtropical conditions continued in three locations began in 2013: 1—Çukurova University, Sarıçam/Adana, 2—Bilici Farm, Ceyhan/Adana, 3—Özler Abdioğlu Farm, Yüreğir, Yakapınar/Adana) with 15 low chilling cherry cultivars planted on 17, 30 and 50 m altitudes, respectively.

Recently, prolonging the cherry season with early and late cherry cultivars extend the cherry exportation season. As a result of the studies carried out at the University of Cukurova, Sweet Heart at high elevations, Royal Lynn® and Royal Tioga® at subtropical climatic conditions were found to be suitable (Figure 6).

Figure 6.

The fruit set of new cherry cultivars at low altitudes.

11. Use of plant growth regulators in cherry

Recently, use of plant growth regulators in cherry cultivation is increasing. Gibberellic acid applications are used in our country to delay ripening period and to increase the fruit size. GA applications on cherry fruits at color changing stage delayed the harvest for 8–10 days. It is better to prune cherry trees together with GA applications to get bigger fruit size as well as delay harvest.

Erger Applications: Manisa Province Sweet Cherry Altitude: 214 m. Cultivar: 0900 Ziraat, Rootstock: Giesela 6.

In this study, chemical applications were found to be effective on breaking dormancy of ‘0900 Ziraat’ sweet cherry cultivar. The chilling duration of the experimental areas were found to be 586 chill units and 1225 h in 2011–2012 winter period while it was 453 chill units and 819 h in 2012–2013 winter period. All treatments were applied (KNO₃ 8%, Erger 6%), on December 15 (45 days before the end of dormancy duration) using 20 L Knapsack Sprayer. The experimental winter period of 2012–2013 was warmer and had lower chilling accumulation. Therefore, no yield could be obtained from the orchards at 150–200 m height. This study was carried out for 2 years (2011–2013). The capacity of Erger (total nitrogen 15.0%, ureic nitrogen 6.1%, nitric nitrogen 5.8%, ammoniacal 3.1%, water soluble calcium oxide 4.7%), Dormex (hydrogen cyanamide) and potassium nitrate (KNO3) for breaking of dormancy in buds of ‘0900 Ziraat’ sweet cherry cultivar trees were determined (Figure 7).

Figure 7.

Comparison of the flowering times of the applications.

12. Cherry harvest, storage and marketing

Cherry fruits do not continue ripening after harvest. Therefore, the right harvest time should be determined carefully. Generally, the harvest starts after the coloring of the fruits.

Fruit cracking in cherries is an important problem in rainy regions. Also, excessive irrigation of the orchards and prolonged stay in a humid environment increase the rate of fruit cracking. Cracked fruits lost their market value, fungal infections occur in fractured parts. Cracking occurs when water enters into the fruit peel and the fruit swells rapidly. In rainy weather, the fruit volume can increase by 10% as the water enters into the ripen fruit.

There are differences between cultivars in terms of susceptibility to cracking. Bing, Van, Karabodur, Early Burlat are sensitive cherry cultivars to cracking. Generally, cherry cultivars with firm fruit flesh are more susceptible to cracking. It was determined that fruit cracking was decreased with the application of burgundy slurry and copper sulphate on trees before harvest. If 450 g borax/decare was given to the cherry orchards that show boron deficiency, it was found that the cracking rate of cherry cultivars was decreased for about 25–50%. Giberellic acid applications to increase the fruit load and fruit set reduce Ca content of the fruit. The use of plant growth regulators that reduce shoot growth and Giberellin synthesis can increase Ca content of the fruit. Spraying Ca 10 days before the harvest decrease cracking and increase the fruit flesh firmness [23].

Various parameters are used to determine the right harvest time in cherries. Among them, the size, fruit color and amount of Brix value are the most commonly used parameters. Generally, the minimum size for exportable cherry fruit is 26 mm. Cherries are nonclimacteric fruits and they do not ripen after harvest. At the harvest time, cherries should contain at least 14–15% Brix value.

Cherry fruits are very sensitive to mechanical damage and deterioration after harvest. For this purpose, cherries should be precooled quickly after harvest and should be packaged properly by using the correct package products. Continuity of the cold chain is also mandatory during the storage and marketing of packaged products [9, 24].

13. Conclusion

Cherry (Prunus avium L.) is originated from South Caucasus, Caspian Sea and North-East Anatolia and the wild cherries are mostly seen at the North Anatolian and the Taurus mountains of Turkey. Turkey is the leader country in the world on sweet cherry production (732.000 tons). Cherry production in Turkey has been performed mostly with ‘0900 Ziraat’ local cherry cultivar, It is heart shaped with pink red fruit flesh, bright, firm, juicy, very large and high-quality fruits, suitable for transportation and long shelf life.

In 1997, “Turkish National Cherry Working Group” was founded and organized 22 working group meetings until today to solve all the problems of cherries. In these meetings, all the research results were shared and discussed among cherry scientists. These problems were pruning, cultivars, fertilization, rootstocks, irrigation, harvesting, pre-cooling, storage, packing, disease and pest control. Under this working group studies, seminars and conferences were organized at the most important cherry producer regions on training, pruning, rootstocks and growing techniques. With the widespread use of yield pruning in grown cherry trees, fruit yield and quality have increased besides the use of dwarf and semi-dwarf cherry rootstocks.

Some favorite and promising foreign sweet cherry cultivars were introduced in the country alternative to 0900 Ziraat cultivar. Especially with the spread of the late maturing Sweet Heart cultivar the cherry season, which ended at the end of July was extended until mid-August.

Many studies have been carried out on the chilling requirements of sweet cherry cultivars and chilling durations of Çukurova region which has a subtropical climate. As a result of working on low chill cherry cultivars, cherry orchards have started to be established in the subtropical regions.