https://orcid.org/0000-0002-2899-2238
ABSTRACT
Turkey has quite a rich genetic diversity in various fruit and plant species. One of them is species in the Prunus genus. In addition, Turkey is the greatest or significant producer of many stone, nut and some fruit species. This study was conducted to determine the effects of intra-species hybridizations of some apricot (Prunus armeniaca L.) cultivars and inter-species hybridization of apricot cultivars with paternal parent plum (Prunus salicina L.) cultivars on fruit set and pomological properties of apricots. In both years of experiments, differences were observed in fruit set ratios of intra and inter-species hybrid combinations based on paternal parent cultivars. Among the apricot × plum inter-species hybrid combinations, the Black Amber plum cultivar was found to be prominent for the investigated parameters. Among the apricot × apricot intra-species hybrid combinations, Palstein group hybrids yielded greater values for the investigated parameters. Present findings may guide further researches to be conducted on intra and inter-species hybridizations of apricots and plums.
Introduction
Turkey has diverse climates ranging from sub-tropical to terrestrial, thus allows both natural growth and economic culture of various plant species (Pınar et al., Citation2019). Turkey has a great genetic diversity in Prunus species. Turkey is among the world’s most important manufacturers of Prunus species such as stone, nut and some fruit species (Uzun et al., Citation2018).
Apricot (Prunus armeniaca L.) is a stone-fruit (Batnini et al., Citation2019). Apricot fruit is among the preferred fruits in human health and nutrition thanks to its biochemical compounds and rich nutritional contents (Gündoğdu, Citation2019). Thus, world annual apricot production was about 4 million tons in 2017 and Turkey with an annual production of 985.000 tons is the leading apricot (Prunus armeniaca L.) producer of the world (FAO, Citation2017). Although Turkey is not among the motherlands, apricot (Prunus armeniaca L.) has well adapted to regional conditions nationwide. Turkish growers experience various problems about fruit set and yield of apricot (Prunus armeniaca L.) orchards.
Self-incompatibility is a widespread mechanism in the Rosacea family including pears (Pyrus communis L.) apple (Malus communis L.), cherry (Prunus avium L.), almond (Prunus dulcis L.) and apricot (Prunus armeniaca L.) (Schuster et al., Citation2013; Yılmaz et al., Citation2016). The primary target in pomiculture is to get high yields economically. Thus, for successful pollination, fruit set and ultimately high yield, foreign pollinators should be used in self-incompatible fruit species (Halder et al., Citation2019).
Receptivity of stigma, the survival of ovule and pollen arrival times to ovary is the key parameters of successful pollination and fertilization (Carpenedo et al., Citation2019). Pollens land on a receptive stigma, germinated pollens then generate a pollen tube and ultimately reach to the surviving ovary to execute fertilization. Since the seeds are consumed in stone-fruits, all the bloomed flowers should turn into fruit (100% fruit set) for maximum yields (Dicenta et al., Citation2000; Khadivi-Khub and Khalili, Citation2017). Care and maintenance practices, ecology, type of pollinator and variety genetics have direct impacts on yields (Brittain et al., Citation2014; Klein et al., Citation2015).
Incompatibility is mostly related to s allele genes with significant impacts on variety of genetics (McCubbin, Citation2017). These genes not only play a great role in fruit sets but also have significant contributions to genetic diversity in s allele-related plant breeding (Gómez et al., Citation2019; Liu et al., Citation2018). Together with s-allele genes, different pollinators also significant effects on fruit mass, shape, size and other parameters. Previous researchers investigated the effects of different pollinators on quality parameters in tangerines (Citrus reticulata L.) (Yıldız and Kaplankıran, Citation2017), cherry (Prunus avium L.) (Cırtlık and Beyhan, Citation2012) and almond (Prunus dulcis L.) .
In this study, intra- and inter-species hybridizations were performed in some apricot cultivars and the effects of pollinators on fruit set and fruit properties of hybrid combinations were investigated.
Materials and Methods
Materials
Experiments were conducted in collection orchards of Alata Horticultural Research Institute, between 2018 and 2019 years in Turkey. The apricot cultivars ‘Ninfa,’ ‘Precoce De Tyrinthe’and ‘Palstein’ were used as mother parents. The apricot cultivars ‘Hacıhaliloğlu,’ ‘Kabaaşı,’ ‘Hasanbey’ and ‘Aprikoz’ were used as father parent in intra-species hybridizations; plum cultivars ‘Black Amber,’ ‘Black Splendor’ and ‘Black Diamond’ were used as father parent in inter-species hybridizations. The collection orchard (36°37ʹ28” N, 34°20ʹ12” E) where the experiments were conducted was established in 2004. The orchard has different apricot cultivars and there are three trees from each cultivar. Orchard soils have a silty-loam texture. Trees are about 15 years old. Meteorological data for flowering, pollination and fertilization periods are provided in .
Table 1. Meteorological data for the experimental years
Method
Pollens of the father parents were collected from the flowers at the balloon stage before the anthers dehiscence. Then, pollens were brushed on emasculated flowers to make hybridizations. Routine cultural practices (irrigation, soil tillage and pruning) were performed accordingly. At the end of dormancy, 3 kg 15–15-15 N-P-K per tree was applied.
Fruits were harvested at harvest maturity, and the harvested number of fruits was used to get fruit set ratios for different hybrid combinations. Hybridizations were performed on March 6, 2018 in the first year and March 8, 2019 in the second year; harvests were practiced on May 25, 2018 in the first year and May 20, 2019 in the second year. For pomological properties, fruit mass, fruit width, fruit length, peal color, flesh color, water-soluble dry matter (WSDM), flesh and stone ratio, pH, acidity (%), stone width, stone length and stone mass parameters were measured (Son, Citation2018).
Experimental data were subjected to statistical analyses with the aid of software SPSS 22.0 (IBM Company, USA) and significant means were compared with Duncan’s multiple range test at P < .05 significance level.
Results and Discussion
Fruit Set Ratios
The greatest fruit set ratio (18.8%) in apricot × apricot intra-species combinations was observed in ‘Precoce De Tyrinthe’ × ‘Hasanbey’ hybridizations with 47 fruits. The lowest fruit set ratios (5.2%) were observed in ‘P. P. Tyrinthe’ × ‘Hacıhaliloğlu’ and ‘P. P. Tyrinthe’ × ‘Aprikoz’ hybrid combinations with 13 fruits in 2018().
Table 2. Fruit set ratios of 2018
The greatest fruit set ratio (3.6%) in apricot x plum inter-species hybridizations was observed in the ‘Precoce De Tyrinthe’ x ‘Black Diamond’ hybrid combination with 11 fruits. The lowest fruit set ratio (0.3%) was observed in the ‘Ninfa’ x ‘Black Amber’ combination with only 1 fruit. Fruit set was not observed in the ‘Precoce De Tyrinthe’ x ‘Black Splendor’ hybrid combination (). In 2019, the greatest fruit set ratio (21.8%) in apricot x apricot intra-species hybrid combinations was observed in the ‘Ninfa’ x ‘Hasanbey’ hybrid combination with 109 fruits. As compared to the other combinations, less fruit set ratios (4.0%) were observed in ‘Ninfa’ x ‘Hacıhaliloğlu,’ ‘Ninfa’ x ‘Aprikoz,’ ‘Ninfa’ x ‘Kabaaşı’ and ‘Palstein’ x ‘Hasanbey’ combinations with 20 fruits in each ().
Table 3. Fruit set ratios of 2019
In apricot x plum inter-species hybrid combinations, fruit set ratios varied between 6.2% and 0.6% corresponding to 3 and 31 fruits. The greatest value was observed in the ‘Precoce De Tyrinthe’ x ‘Black Amber’ combination and the lowest value was seen in the ‘Palstein’ x ‘Black Amber’ combination. In inter-species hybrid combinations, fruit set was not observed in ‘Ninfa’ x ‘Black Diamond,’ ‘Palstein’ x ‘Black Splendor’ and ‘Palstein’ x ‘Black Diamond’ combinations (). Taha and Elsherif (Citation2015) conducted a study about the effects of intra-species hybridizations and different pollinators on fruit set and quality in apricot and reported fruit set ratios of between 18.0% and 21.7% based on pollinator cultivars. In the present study, apricot intra-species hybridizations yielded similar fruit set ratios.
Inter-species hybridizations between apricot and plum cultivars (P. armeniaca × P. cerasifera) generally had quite low fruit set ratios (Rubio et al., Citation2011; Szymajda et al., Citation2015). As compared to inter-species hybridizations, present intra-species hybridizations also yielded quite low fruit set ratios and fruit set was not observed in wild species. In this sense, the present findings comply with those earlier ones.
Pomological Properties
In intra-species hybrid combinations of 2018, the lowest fruit mass (46.46 g) was observed in ‘Precoce De Tyrinthe’ x ‘Hacıhaliloğlu’ combination and the greatest fruit mass (63.99 g) was observed in ‘Precoce De Tyrinthe’ x ‘Hasanbey’ hybrid combination ().
Table 4. Pomological characteristics of apricot x apricot hybrid combinations in 2018
In 2019, the lowest fruit mass (39.71 g) was observed in the Ninfa x Kabaaşı combination and the greatest fruit mass (71.97 g) was observed in the Palstein x Aprikoz combination (). In intra-species hybrid combinations of 2018, the lowest fruit width (44.12 mm) was obtained from Ninfa x Hasanbey combination, and the greatest fruit width (47.72 mm) was obtained from Precoce De Tyrinthe x Hasanbey combination; in 2019, the lowest fruit width (39.54 mm) was obtained from Ninfa x Kabaaşı combination and the greatest fruit width (50.99 mm) was obtained from Palstein x Aprikoz combination.
Table 5. Pomological characteristic apricot x apricot hybrid combinations in 2019
Differences in fruit skin and flesh color values of the hybrid combinations, respectively, varied between 2.97 and 2.95 in 2018 and between 3.30 and 3.03 in 2019. The average WSDM content of apricot x apricot combinations was 8.38% in 2018 and 9.01% in 2019.
In 2018, the lowest flesh/stone ratio (14.42) was observed in the Precoce De Tyrinthe x Hacıhaliloğlu hybrid combination and the greatest ratio (20.40) was observed in the Precoce De Tyrinthe x Hasanbey combination. In 2019, the lowest flesh and stone ratio (15.06) was observed in the Palstein x Hasanbey combination and the greatest ratio (28.83) was observed in the Precoce De Tyrinthe x Kabaaşı hybrid combination. The average pH was 3.59 in 2018 and 3.51 in 2019. Ninfa x Hacıhaliloğlu combination was found to be prominent for pH (3.68). Average acidity was measured as 0.62 in 2018 and 0.71 in 2019. Precoce De Tyrinthe x Hasanbey combination had greater acidity values than the other combinations.
In apricot x apricot intra-species hybrids, there were differences in stone parameters of mother parent and normally pollinated fruits of hybrid combinations in both years. In both years, the greatest stone widths (24.03 and 28.65 mm) were observed in Ninfa x Aprikoz hybrid combinations. The greatest stone length was observed in the Precoce De Tyrinthe x Hacıhaliloğlu combination (29.69 mm) in 2018 and in Precoce De Tyrinthe x Hasanbey combination (32.16 mm) in 2019. The greatest stone mass was observed in the Ninfa x Aprikoz combination (3.31 g) in 2018 and in Palstein x Hasanbey combination (4.18 g) in 2019 ().
In 2018, in Apricot x Plum hybrid combinations, average fruit mass was 30.73 g, fruit length was 40.19 mm, fruit width was 36.25 mm, skin color was 2.00, flesh color was 3.00, WSDM was 9.00%, flesh/stone ratio was 11.24, pH was 3.89, acidity was 0.63%, stone width was 21.82 mm, the stone length was 25.75 mm and stone mass was 2.51 g ().
Table 6. Pomological characteristic apricot x plum hybrid combinations in 2018
In 2019, among the inter-species hybrid combinations, Palstein x Black Amber was found to be prominent for fruit mass (70.58 g), fruit width (52.25 mm), fruit length (50.37 mm), skin color (3.80) and flesh color (4.10) values. As compared to open-pollinated fruits, mother parents did not have positive effects on WSDM and flesh and stone ratios. The greatest WSDM content (10.89%) was observed in the Palstein x Black Amber combination and the greatest flesh/stone ratio (24.56) was observed in the Precoce De Tyrinthe x Black Amber combination. The greatest pH (3.85) was observed in the Ninfa x Black Splendor combination.
As it was in the other parameters of inter-species hybrid combinations, the Palstein x Black Amber combination had greater stone mass, stone length and stone width values ().
Table 7. Pomological characteristic apricot x plum hybrid combinations in 2019
Previous researchers reported fruit mass values of some early apricot cultivars as between 37.7 and 58.83 g (Son, Citation2018), fruit lengths as between 42.21 mm (Çağataybey) and 50.13 mm (Alatayıldızı) (Bircan et al., Citation2010), fruit widths as between 34.81 and 49.68 mm (Karaat and Serçe, Citation2019).
WSDM contents of some early apricot cultivars were reported as between 11.06% and 14.06% (Son and Bahar, Citation2018), flesh and stone ratios as between 10.4 and 20.8 (Bilgin et al., Citation2016), pH values as between 3.31 and 4.25 (Özdoğru et al., Citation2014), titratable acidity values as between 0.2% and 0.87% (Polat, Citation2018), stone mass values as between 1.75 and 2.43 g (Bilgin et al., Citation2016). Present findings comply with the results of earlier studies. Differences in some parameters are mostly attributed to differences in cultivars, ecological conditions and analysis methods.
Conclusion
Hybridization breeding is commonly used especially in fruit breeding programs. Despite a low chance of success, the inter-species hybridization technique may have significant contributions to breeding studies through improving genetic variation and diversity. This study was conducted to investigate the effects of different apricot x apricot (intra-species) hybrid combinations and apricot x plum (inter-species) hybrid combinations on fruit set and pomological properties of stone-fruit species. Resultant hybrid seeds may guide further breeders in developing new genotypes with the potential of candidate cultivar and rootstock in pomiculture. Present findings may also guide further research to be conducted on intra and inter-species hybridizations of apricots and plums.
Acknowledgments
Authors thanks Erciyes University for financial support.
Additional information
Funding
References
- Batnini, M. A., H. Bourguiba, N. Trififarah, and L. Krichen. 2019. Molecular diversity and phylogeny of Tunisian Prunus armeniaca L. by evaluating three candidate barcodes of the chloroplast genome. Sci. Hortic. 245:99–106. doi: 10.1016/j.scienta.2018.09.071.
- Bilgin, N.A., Y. Evrenosoğlu, K.U. Yılmaz, T. Yiğit, R. Kokargül, K. Gökalp, and A. Mısırlı. 2016. Melez Kayısı Populasyonunun Meyve Kalite Özellikleri ile İlgili Genel Değerlendirme. Ege Üniv. Ziraat Fak. Derg. 53(1):25–34. (in Turkish).
- Bircan, M., H. Pinar, C. Yilmaz, S. Paydaş, and N. Kaşka. 2010. The apricot breeding program among some Turkish and foreign cultivars. Acta Horticulturae. 862:103–108. doi: 10.17660/ActaHortic.2010.862.15.
- Brittain, C.C., A. Kremen, and A.M. Garber. 2014. Pollination and plant resources change the nutritional quality of almonds for human health. Plos ONE 9(2):e90082. doi: 10.1371/journal.pone.0090082.
- Carpenedo, S., C.B. Raseira M Do, R. C. Franzon, D. H. Byrne, and J.B. da Silva. 2019. Stigmatic receptivity of peach flowers submitted to heat stress. Acta Scientiarum. Agronomy 42(1):e42450. doi: 10.4025/actasciagron.v42i1.42450.
- Cırtlık, B. K., and N Beyhan. 2012. Amasya yöresinde yetiştirilen bazı önemli yerel kiraz çeşitlerinin Ziraat 900 için tozlayıcı olarak kullanılabilirliklerinin araştırılması. Anadolu Tar. Bil. Dergisi. 27(2):64–69. (in Turkish).
- Dicenta, F., P. Martínez-Gómez, and E. Ortega. 2000. Cultivar pollinizer does not affect almond flavor. HortScience 35(6):1153–1154. doi: 10.21273/HORTSCI.35.6.1153.
- FAO. 2017. Food and Agriculture Organization of the United Nations. “Crops data”, http://www.fao.org/faostat/en/#data
- Gómez, M.E., F. Dicenta, I. Batlle, A. Romero, and E. Ortega. 2019. Cross-incompatibility in the cultivated almond (Prunus dulcis L.): Updating, revision and correction. Sci. Hortic. 245:218–223. doi: 10.1016/j.scienta.2018.09.054.
- Gündoğdu, M. 2019. Effect of rootstocks on phytochemical properties of apricot fruit. Turkish Journal of Agriculture and Forestry 43(1):1–10. doi: 10.3906/tar-1803-99.
- Halder, S., S. Ghosh, R. Khan, A.A. Khan, T. Perween, and A. Hasan. 2019. Role of pollination in fruit crops: A review. The Pharma Innovation Journal 8(5):695–702.
- Karaat, F., and E. Serçe. 2019. Total phenolics, antioxidant capacities and pomological characteristics of 12 apricot cultivars grown in Turkey. ADYÜTAYAM 7:1:46–60.
- Khadivi-Khub, A., and Z. Khalili. 2017. A breeding project: The selection of promising apricot (Prunus armeniaca L.) genotypes with late blooming time and high fruit quality. Sci. Hortic. 216:93–102. doi: 10.1016/j.scienta.2016.12.027.
- Klein, A.M., S.D. Hendrix, Y. Clough, A. Scofield, and A. Kremen. 2015. Interacting effects of pollination, water and nutrients on fruit tree performance. Plant Biol 17(1):201–208. doi: 10.1111/plb.12180.
- Liu, S., Y. Zhang, Q. Feng, L. Qin, C. Pan, and A.T. Lamin-Samu. 2018. Tomato auxın response factor 5 regulates fruit set and development via the mediation of auxin and gibberellin signaling. Sci. Rep. 8:2971. doi: 10.1038/s41598-018-21315-y.
- McCubbin, A. 2017. Breeding barriers: Duplicate S genes form new barrier. Nature Plants. 3:17100. doi: 10.1038/nplants.2017.100.
- Özdoğru, B., F. Şen, N.A. Bilgin, and A. Mısırlı. 2014. Bazı Sofralık Kayısı Çeşitlerinin Depolanma Sürelerinin Belirlenmesi. ÇOMÜ Zir. Fak. Derg., (COMU J. Agric. Fac). 2(2):89–96. (in Turkish).
- Pınar, H., A. Uzun, M. Unlu, and M. Yaman. 2019. Genetic diversity in Turkish banana (Musa cavendishii) genotypes with DAMD markers. Fresenius Environ. Bull. 1:459–463.
- Polat, M. 2018. Yield and certain pomological characteristics of organically grown ‘Alyanak’ and ‘Hasanbey’ apricots (Prunus armeniaca L.). Fresenius Environ. Bull. 27(6):4433–4439.
- Rubio, M., A. García‐Ibarra, F. Dicenta, and P. Martínez‐Gómez. 2011. Plum pox virus (Sharka) sensitivity in Prunus salicina and Prunus cerasifera cultivars against a dideron‐type isolate. Plant Breed. 130:283–286. doi: 10.1111/j.1439-0523.2010.01813.x.
- Schuster, M., C. Grafe, E. Hoberg, and W. Schütze. 2013. Interspecific hybridization in sweet and sour cherry breeding. Acta Horticulturae. 976:79–86. doi: 10.17660/ActaHortic.2013.976.7.
- Son, L. 2018. Bazı Sofralık Kayısı Çeşitlerinin Silifke/Mersin Ekolojik Koşullarındaki Verim ve Kalite Özellikleri Üzerine Araştırmalar. Çukurova J. Agric. Food Sci. 33(2):17–22. (in Turkish).
- Son, L., and A. Bahar. 2018. Bazı sofralık erkenci kayısı (Prunus armeniaca L.) çeşitlerinin Manavgat/Antalya ekolojik şartlarındaki verim ve kalite özellikleri üzerinde araştırmalar. Mediterranean Agricultural Sciences.31(1):1–4. (in Turkish). doi:10.29136/mediterranean.363618.
- Szymajda, M., B. Napiórkowska, M. Korbin, and E. Żurawicz. 2015. Studies on the interspecific crossingcom- patibility among three Prunus species and their hybrids. Hortiscience (Prague). 42:70–82. doi: 10.17221/8206-HORTSCI.
- Taha, N., and H. Elsherif. 2015. Increasing fruit set, yield and fruit quality of ‘Canino’ apricot trees under two different soil conditions. Br. J. Appl. Sci. Technol. 10(2):1–18. doi: 10.9734/BJAST/2015/18831.
- Uzun, A., M. Yaman, H. Pınar, N. Çetin, and A. Say. 2018. Türkiye’de Ekonomik Olarak Yetiştiriciliği Yapılan Sert Çekirdekli Meyvelerin Üretim Projeksiyonu. Bahçe. 47:79–83. (in Turkish).
- Yıldız, E., and M. Kaplankıran. 2017. The effect of cross-pollination on fruit set and quality in Robinson and Fremont mandarins. Ege Üniversitesi Ziraat Fakültesi 54:107–112. (in Turkish). doi: 10.20289/zfdergi.297992.
- Yılmaz, K.U., B. Başbuğ, K. Gürcan, H. Pınar, J. Halasz, S. Ercişli, and A. Uzun. 2016. S-genotype profiles of Turkish apricot germplasm. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 44(1):67–71. doi: 10.15835/nbha44110350.