Research Article

Selection and Pomological Characterization of Superior Native Almonds (Amygdalus Communis L.) in Siirt, Turkey

Canan Celapkulu¹ and Fikri Balta^2*

¹Antalya Seed Certification and Testing Directorate, Aksu, Antalya, Turkey

²Faculty of Agriculture, Department of Horticulture, Ordu University, Ordu, Turkey

Submission: May 09, 2024;Published: June 14, 2024

*Corresponding author: Fikri Balta, Faculty of Agriculture, Department of Horticulture, Ordu University, Ordu, Turkey, E-mail: baltaf04@yahoo.com

How to cite this article: Canan Celapkulu, Fikri Balta. Selection and Pomological Characterization of Superior Native Almonds (Amygdalus Communis L.) in Siirt, Turkey. JOJ Hortic Arboric. 2024; 4(3): 555640. DOI: 10.19080/JOJHA.2024.04.555640.

Abstract

Turkey has a large number of seedling almond trees, which originate from seeds and show great variability, especially in terms of fruit characteristics. This valuable germplasm that has survived until today has the potential to both register new varieties directly and use them as parents in almond hybridization studies. The study was conducted to select promising almond (Prunus amygdalus L.) genotypes propagated by seeds in Siirt province, Turkey. The whole native population consisting of seedling almond trees growing under unirrigated conditions were screened based on late flowering, superior nut traits and tree productivity. 18 promising genotypes were selected from a natural population of approximately 34.200 seedling almond trees. Promising genotypes had a range of 5.14 g and 8.17 g for nut weight, 1.03 g and 1.46 g for kernel weight, 16.3% and 22.6% for kernel ratio, 3.12 mm and 4.65 mm for shell thickness, 0% and 20% for double kernel percentage. They had hard shelled nuts and sweet kernels. Eight genotypes had light-colored kernels. Two genotypes (56-AY-19 and 56-AY-97) produced very large-sized nuts. The results revealed the potential of promising genotypes to contribute as material to breeding studies and become new local cultivar candidates.

Keywords: Almond; Prunus amygdalus L.; Superior genotype; Selecting; Siirt

Abbreviations: By including the abbreviations of Table 4 and Table 5, the number of these 4 abbreviations has been increased: A: August; F: February; C: Closed; KS: Kernel size; M: March; ML: Medium large; NWE: Nut weight (g); SH: Shell hardness; SS: Suture of shell; SW: Slightly wrinkled; Vh: Very hard; VL: Very large; W: Wrinkled.

Introduction

Cultivated almond (Prunus dulcis [Mill.] D.A. Webb, syn. Prunus amygdalus (L.) Batsch) is widely distributed from Asia to North America [1]. Almond is one of the popular nuts whose production and consumption is increasing today. It has been reported that the remarkable increase in almond production in California is also associated with the development of consumer awareness due to its benefits on human nutrition and health [2]. Almond fruit is included in nutritional diets with its fatty acids, proteins, dietary fiber, complex carbohydrates, vitamin E, polyphenols and many minerals [3,4]. Almond is beneficial for various diseases such as heart, cancer, joint, rheumatism and skin diseases, and that it increases the level of HDL (high density lipoproteins) in the blood and reduces the level of LDL (low density lipoproteins) with the fatty acids and phytosterols it contains [5,6].

In Anatolia, almond is cultivated in almost every region except the Eastern Black Sea coastal regions and plateaus, but its culture is more common in the Aegean, Mediterranean, Marmara and Southeastern regions. It was emphasized that Southeastern Anatolia has the potential to become an important almond cultivation center in the future as a result of the expansion of irrigation facilities [7]. Almond production in various countries is based mostly on selected seedling populations consisting of different genotypes. These genotypes, adapted to local production areas, are the result of natural selection. The culture of continuous seed propagation, which has been practiced in different areas of Anatolia since ancient times, has led to the emergence of large-scale seedling almond populations [8,9]. Unfortunately, these populations, which constitute local almond genetic resources, are gradually decreasing and even in danger of extinction in some places. Seedling almond populations with wide genetic diversity may contain valuable individuals or chance seedlings with high resistance to various biotic and abiotic stress conditions. Many commercial almond cultivars, which have an important place in world almond production, have been released as chance seedlings [10,11].

Genetic diversity in almonds is of great importance in terms of determining gene pools, developing conservation strategies and identifying genetic resources [12,13]. Genetic diversity of native almond populations is a need for a successful breeding program and provides many opportunities for breeding efforts and introduction of promising genotypes [14].

Collecting, evaluating and identifying promising genotypes from local populations is one of the basic methods in almond breeding programs [14,15]. Selecting valuable individuals from seedling tree populations in different areas can contribute to the progress of breeding. Related studies contribute to the discovery of superior genotypes within seedling almond populations and the conservation of genetic resources [15-17]. Morphological characterization of germplasm collections is the reference for plant breeders [18]. The aim of this research is to examine almond genotypes propagated by seeds in Tillo and Kurtalan districts of Siirt province located in southeastern Anatolia region and to determine the nut and tree traits of most promising genotypes for future breeding studies.

Materials and Methods

Research area

Siirt province (41° 57' east longitude and 37° 55' north latitude) is in the southeast of Turkey and in the southwest of the Lake Van basin (Figure 1). Most of the province is surrounded by mountains. Its altitude is 895 m. In the province, summers are hot and dry, and winters are cold. Monthly mean temperature varies between 2.7 °C (January) and 30.7 °C (July). Its annual total rainfall is 718 mm. It receives the lowest rainfall in July (2.7 mm) and the highest rainfall in March (113.3 mm) (Figure 2). Tillo and Kurtalan are two of the districts of Siirt province. They exhibit climate traits like Siirt.

Plant Materials

This research was conducted for three years (2010-2012) in seedling almond populations in Tillo and Kurtalan districts of Siirt province (Southeastern Anatolia). In the first year, 34.200 seedling almond trees growing under unirrigated conditions in Tillo and Kurtalan districts were screened based on late flowering, superior nut traits and tree productivity. In seedling population, 103 genotypes were examined and their detailed nut and tree traits were recorded. Among them, those with kernel weight higher than 0.85 g were choosen and thus the number of genotypes was reduced to 57 in 2011. These genotypes were evaluated based on the Weighted Ranking Method [15-17,20,21], and 18 genotypes were selected as promising. In addition, the range and distribution of some nut and kernel traits and phenological data were evaluated in the almond genotypes examined in the first year (2010) and the second year (2011).

Tree traits

Trunk circumference at 60 cm height from the ground (cm), tree height (m), tree shape, yield and altitute were described. Weeks of the bud breaking, first flowering, full flowering, end of flowering, and harvest dates were recorded for all genotypes.

Nut and kernel traits

Nut traits examined were nut thickness, nut width, nut length, shell thickness, nut weight, nut size, shell hardness, nut shape, shell porosity, suture of shell and ease of hulling. Kernel traits were kernel thickness, kernel width, kernel length, kernel weight, kernel ratio, the number of kernel per ounces, kernel size, double kernel ratio, sound of kernel, kernel taste, kernel shriveling, kernel pubescence and kernel color. Nut weight (fruit in shell) and kernel weight (g) were determined using a digital scale sensitive to 0.01 g. Dimensions (mm) and shell thickness (mm) of the nuts were measured with a digital caliper. Nut and kernel traits were determined on randomly choosen 30 nuts for each genotype [17,20-22].

Results and Discussion

Phenological observation data. Phenological observation data were recorded on a weekly basis for two years (2011-2012) for both the 57 genotypes evaluated in the second year and the 18 promising genotypes and are presented in Table 1 and Table 2.

The first flowering occurred in the last week of February and the first and second weeks of March in the second year, and in the first and second weeks of March in the third year (Table 1). The genotypes were in full bloom in the first three weeks of March in the second year, and in the second and third weeks of March in the third year. Harvest times were 20-28 August in the first year and 24-27 August in the second year. Phenological observation data indicated genetic diversity in terms of flowering behavior.

The numbers I, II, III and IV indicate the week of the relevant month.

The numbers I, II, III and IV indicate the week of the relevant month. F: February, M: March, A: August.

In almonds, heritability of flowering time is high [23]. Early flowering limits almond cultivation in areas where late spring frosts occur. The flowering dates may vary from year to year depending on winter conditions [16]. Therefore, the development of late-flowering almond cultivars is among the main objectives of most breeding programs [10,24]. It is extremely important to select high quality almonds that are not affected by late spring frosts in almond growing ecologies. In this research, promising genotypes that bloom fully in the third week of March in the first and second years offer value.

The growing altitudes of 18 promising genotypes varied from 930 to 1225 (Table 2). In the promising genotypes, bud breaking and first flowering occurred between the last week of February in 2011 and the second week of March, and between the first and second week of March in 2012. Full flowering was in the first week of March for 4 genotypes, in the second for 2 genotypes and in the third week of March for 12 genotypes in 2011. In 2012, the week of full flowering did not change in 12 genotypes, while it occurred 1 week later in 6 genotypes compared to the previous year. Thus, full flowering was the third week of March in the first and second year for most promising genotypes. For the majority of promising genotypes, end of flowering was the third week of March (14 genotypes) in the first year and the fourth week of March (16 genotypes) in the second year. Phenological observation data indicated genetic diversity in terms of flowering behavior. Studies of almond germplasm from different areas also show year-to-year differences in flowering dates and harvest times [15,25,26].

Differences in flowering behavior in almonds may result from ecological conditions such as location, climate, temperature and altitude, as well as the genetic structure of the almond trees [11,27]. In related studies conducted in various ecologies in Anatolia, flowering season differences of many promising almond genotypes have attracted attention. Regional flowering seasons of promising genotypes, depending on the year, have been reported as early-mid April and early May in Kemaliye district of Erzincan Province [21], early March to early April in Kahramanmaras [28], late April in the Van Lake Basin [29], mid-March to mid-late April in Elazığ [16], mid-March to mid-April in Pertek district (Tunceli) [22], late March to mid-late April in Isparta [17], early March in Derik district (Mardin) [30], mid-February to early March in Yenipazar, Bozdoğan and Karacasu districts of Aydın province [15], mid-February to late March in Araban and Yavuzeli districts of Gaziantep [31] and mid-December to mid-January in Datca peninsula of Mugla [32].

In promising genotypes, harvest times varied between 21 August and 28 August in the first year and between 23 August and 27 August in the second year. Harvest seasons of almond genetic resources may exhibit variations [26]. Relevant research reveals that harvest seasons vary depending on regions, years and climatic conditions, as well as genotypic characteristics. Regional or local harvest seasons for promising almond germplasm have been reported as mid-August in the Van Lake Basin [29], early to late September in Pertek (Tunceli) district [22], early to mid-March in Çınar (Diyarbakır) district [33], late July to early September in Yenipazar, Bozdogan and Karacasu districts of Aydın [15], mid-September to early October in Yesilyurt district of Malatya [34] and early July to early August in Datca peninsula of Mugla [32].

Nut and Kernel Traits

Table 3 shows the range and distribution of some nut and kernel traits in almond genotypes examined in the first and second year of the study. The 103 genotypes examined in the first year had a range of 1.80-7.80 g for nut weight, 0.46-1.45 g for kernel weight, 13-31% for kernel ratio, 1.90-4.70 mm for shell thickness, 0-32.5% for double kernel ratio and 32.5-100% for sound of kernel. The 57 genotypes investigated in the second year exhibited a range of 2.23-8.64 g for nut weight, 0.60-1.55 g for kernel weight, 14-26% for kernel ratio, 2.61-4.65 mm for shell thickness, 0-50% for double kernel ratio and 60-100% for sound of kernel. Data indicate genetic variation regarding nut and kernel characteristics of the genotypes. Almond germplasm can show a wide variation in nut characteristics [14,16,26,35].

Table 4 exhibits the nut traits of 18 promising genotypes. They had a range of 15.3-18.3 mm for nut thickness, 23.1-32.2 mm for nut width, 32.5-41.7 for nut length and 3.12-4.65 mm for shell thickness. All genotypes had nut weight over 5 g. Nut weight ranged from 5.14 g to 8.17 g. Two genotypes (56-AY-19 and 56-AY-97) produced very large-sized nuts. The number of large-sized genotypes was 11. The five genotypes had medium large-sized nuts. Promising genotypes had hard-shelled nuts. The six genotypes were heart shaped. Nut shape was ellipse in five genotypes, long oval in five genotypes, long narrow in one genotype and round one genotype. The nuts of six genotypes had less pored shells. Shell porosity was intermediate pored for 9 genotypes and densely pored for three genotypes. All genotypes produced nuts with closed suture of shell. Hulling was easy for 11 genotypes, and ease of hulling of the remaining 7 genotypes was medium (Table 4). In related research, many promising almond genotypes have been identified in terms of nut traits such as nut shape, shell porosity, suture of shell and easy hulling [31,32,34,36-39].

Preferences regarding shell hardness in almonds may vary from country to country. Many Californian and Spanish almond cultivars have hard-shelled nuts [11]. Hard-shelled almond varieties are more preferred in Mediterranean countries [40]. The reasons why hard-shelled almonds are preferred in the Mediterranean region are that they adapt more easily to non-irrigated conditions, are more resistant to attacks by birds, rodents and insects, can be stored for a long time and thus maintain their commercial value throughout the season [41].

Kernel traits of promising genotypes were presented in Table 5. They had a range of 5.7-7.7 mm for kernel thickness, 13.5-17.4 mm for kernel width and 22.1-27.6 mm for kernel length. Kernel size of two genotypes (56-AY-19 and 56-KR-75) was very large. Number of kernels per ounce varied between 19.4 and 27.5. Kernel ratio was between 15.8% and 22.6% and was generally low due to the hard-shell structure of the genotypes, but kernel size was large size for 12 genotypes and medium large for 4 genotypes. Kernel weight varied from 1.03 g to 1.46. Five genotypes (56-AY-19, 56-AY-74, 56-AY-75, 56-AY-86 and 56-AY-97) had kernel weight higher than 1.3 g. Our promising genotypes were comparable in terms of kernel weight and size to many promising selected local almond genotypes with kernel weight over 1 g, very large and large kernel size, reported by various researchers [16, 22, 31, 32, 39,42-44]. It is desired that commercial almond cultivars have kernel weight over 1 g [10,11]. Many almond varieties or genotypes have been reported to produce fruits weighing more than 1.0 g in the USA, Spain, Italy and France [45].

C: Closed; ML: Medium large; NWE: Nut weight (g); SH: Shell hardness; SS: Suture of shell; Vh: Very hard; VL: Very large.

KS: Kernel size; ML: Medium large; VL: Very large; SW: Slightly wrinkled; W: Wrinkled.

On the other hand, double kernel, sound of kernel, kernel color, kernel taste, kernel shriveling and kernel pubescence are also the characteristics emphasized in almond breeding efforts [10,40]. Although double kernel is an undesirable trait, its percentage varies between varieties depending on climatic conditions. The majority of genotypes did not produce double kernels. Double kernel ratio of 4 genotypes was between 5% and 20%. Climatic conditions during both ovule development and fertilization periods can affect the double kernel ratio [46]. Especially low temperatures before and during flowering cause double kernel ratio to increase [47]. Sound of kernel of 14 genotypes was 100%. Light-colored sweet kernel formation is the desired trait [10]. Eight genotypes had light-colored kernels. All promising genotypes produced sweet kernels. Kernel shriveling was smooth for 8 genotypes, slightly wrinkled for 9 genotypes and wrinkled for one genotype. Kernel pubescence was low for the majority of genotypes. In related studies, many researchers have identified various promising genotypes with similar characteristics in terms of double kernel, sound of kernel, kernel color, kernel taste, kernel shriveling and kernel pubescence [22,31,32,43, 48] Figure 3 shows some promising genotypes.

Tree traits of promising genotypes

Tree heights of the genotypes varied 4.5 m to 9 m (Table 6). Their trunk circumferences were between 52 cm and 200 cm. Half of the genotypes had a spreading tree habit. Tree growth habit was spreading, spreading to upright, upright and very spreading Many researchers described similar tree habits for almond genotypes [15,18,26,29]. In addition, tree yield was high in 10 genotypes and medium in 8 genotypes. Productivity in almonds is genotype and year dependent linked to the climatic conditions and to the physiological status of the trees [49].

Conclusion

The findings of the study revealed a wide variability in nut and kernel characteristics of the seed-originated almond genotypes investigated. The data determined in this research were obtained from almond genotypes grown in unirrigated and neglected conditions. It can also be expected that promising genotypes would exhibit better results under controlled conditions. All of promising genotypes producing sweet kernels weighing over 1 gram attracted attention with their many nut and kernel characteristics. The results revealed the potential of promising genotypes to contribute as material to breeding studies and become new local cultivar candidates.

Conflict of Interest

Celapkulu C and Balta F declare that they have no competing interest

References

1. Browicz K, Zohary D (1996) The Genus Amygdalus (Rosacecae): Species, Relationships, Distribution and Evolution under Domestication. Gen Res Crop Evol 43: 229-247.
2. Chen CY, Lapsley K, Blumberg J (2006) A nutrition and health perspective on almonds. J Sci Food Agric 86(14): 2245-2250.
3. Jaceldo-Siegl K, Sabaté J, Rajaram S, Fraser GE (2004) Long-term almond supplementation without advice on food replacement induces favourable nutrient modifications to the habitual diets of free-living individuals. British J Nutr 92(3): 533-540.
4. Wien M, Bleich D, Raghuwanshi M, Gould-Forgerite S, Gomes J, et al. (2010) Almond consumption and cardiovascular risk factors in adults with prediabetes. J Amer Coll Nutr 29(3): 189-197.
5. Berryman CE, Preston AG, Karmally W, Deckelbaum RJ, Kris-Etherton PM (2011) Effects of almond consumption on the reduction of LDL-cholesterol: a discussion of potential mechanisms and future research directions. Nutr Rev 69(4): 171-185.
6. Kodad O, Fernández-Cuesta Á, Karima B, Velasco L, Ercişli S, et al. (2015) Natural variability in phytosterols in almond (Prunus amygdalus) trees growing under a southern Mediterranean climate. J Hort Sci Biotechnol 90(5): 543-549.
7. Kaşka N, Küden A, Küden AB (1998) Almond production in southeast Anatolia. Acta Hort 373: 253-258.
8. Mısırlı A, Gülcan R (2000) Almond growing in Turkey. Nucis 9: 3-6.
9. Aşkın MA, Balta MF, Tekintaş FE, Kazankaya A, Balta F (2007) Fatty acid composition affected by kernel weight in almond [Prunus dulcis (Mill.) DA Webb.] genetic resources. J Food Comp Analysis 20(1): 7-12.
10. Kester DE, Assay R (1975) Almonds. Advances in fruit breeding. Purdue University Press, Westlafayette, pp. 628.
11. Kester DE, Gradziel M, Grassely C (1991) Almonds (Prunus) Genetic Resources of Temperate Fruit and Nut Crops-2. Wageningen, Int Society for Horticul Sci pp. 698-758.
12. Gradziel TM, Martínez-Gómez P, Dicenta F, Kester DE (2001) The utilization of related Prunus species for almond variety improvement. J Amer Pomol Soc 55: 100-108.
13. Szikriszt B, Hegedûs A, Halász J (2011) Review of genetic diversity studies in almond (Prunus dulcis). Acta Agron Hung 59: 379-395.
14. Khadivi A, Safdari L, Hajian MH, Safari F (2019) Selection of the promising almond (Prunus amygdalus ) genotypes among seedling origin trees. Sci Horticult 256: 108587.
15. Gülsoy E (2012) Selection of native almonds (Prunus amygdalus ) grown in Yenipazar, Bozdoğan and Karacasu districts of Aydın. PhD Thesis. Yüzüncü Yıl University, Van, Turkey.
16. Balta MF (2002) A study on selection breeding of almonds (Prunus amygdalus ) in Elazığ province and Ağın district. PhD thesis. Yüzüncü Yıl University, Van, Turkey.
17. Yıldırım AN (2007) Selection of almonds ( amygdalus L.). PhD Thesis. Adnan Menderes University, Aydın, Turkey.
18. Sepahvand E, Khadivi-Khub A, Momenpour A, Fallahi E (2015) Evaluation of an almond collection using morphological variables to choose superior trees. Fruits, 70(1): 53-59.
19. Anonymous (2023) Turkish State Meteorological Service.
20. Gülcan R (1985) Descriptor list for almond (Prunus amygdalus). International Board for Plant Genetic Resources, Rome.
21. Aslantaş R (1993) A study on the selection breeding of almonds (Amygdalus communis ) in Kemaliye. MsC thesis. Ataturk University, Erzurum, Turkey.
22. Ağlar E (2005) Selection of almonds (Prunus amygdalus ) from Pertek (Tunceli). MSc Thesis. Yüzüncü Yıl University, Van, Turkey.
23. Kester DE, Hansche PE, Beres W, Asay RN (1977) Variance components and heritability of nut and kernel traits in Almond. J Amer Soc Hort Sci 102: 264-266.
24. Socias I Company R (1997) Qualitative traits in almond. Nucis 6: 6-9.
25. Talhouk SN, Lubani KT, Parmaksizian LS, Nehme GA (1997) Survey and characterization of almond germplasm in Lebanon. Acta Hortic 470: 101-109.
26. Khadivi-Khub A, Etemadi-Khah A (2015) Phenotypic diversity and relationships between morphological traits in selected almond (Prunus amygdalus) germplasm. Agroforestry Systems 89: 205-216.
27. Grasselly C (1990) Almond production and industry in europe, north africa and the middle east. Nut production and industry in europe, near east and north africa. Reur Technical Series 13: 95-105.
28. Beyhan Ö, Şimşek M (2007) A research on breeding by selection of wild almond ( amygdalus L.) forms in Kahramanmaraş cental province. Bahçe 36 (1-2): 11-18.
29. Balta F, Yarılgaç T, Balta F (2001) Fruit characteristics of native almond selections from the lake Van region. J Amer Pomol Soc 55: 58-61.
30. Şimşek M, Osmanoğlu A (2010) Selection of native growing almonds (Prunus amygdalus ) from Derik (Mardin) province in Turkey YYYU J Agric 20: 171-182.
31. Yılmaz A, Okay Y (2018) Selection of superior genotypes for nut characteristics within native almond (Prunus amygdalus Batsch) populations. In XXX International Horticultural Congress IHC2018: Int Sym on Nuts and Mediterranean Climate Fruits, Carob and X 1280 p. 63-70.
32. Bozkurt T, Ercişli S, Sakar E (2023) Nut, kernel and tree characteristics of selected seed propagated almonds (Amygdalus communis) in Datça Peninsula. Erwerbs-Obstbau 65(5): 1489-1497.
33. Şimşek M (2011) Almond selection in Çınar district. Bingol Univ J Sci 1: 32-36.
34. Büyükfirat M, Gülsoy E, Aslantaş R (2022) Selection of almonds (Prunus amygdalus) in Yeşilyurt (Malatya) district. Turk J Agric Nat Sci 9(2): 377-386.
35. Göksu A, Yıldız K (2024) Investigation of the variability observed in genotypes in Adıyaman natural almond population by multivariate analysis. Anadolu J Agric Sci 39(1): 1-10.
36. Gerçekcioğlu R, Güneş M (1999) A research on improvement of almond ( amygdalus L.) by selection of wild plants grown in Tokat central district. In: XI. Grempa Meeting on Pistacios and Almonds. Ş. Urfa (Turkey), p. 43.
37. Balta MF, Aşkın MA, Yarılgaç T, Kazankaya A (2003) Maden ilçesinde doğal olarak yetiştirilen bademlerin meyve ö Proceedings of Turkey IV. Horticultural Plants Congress, Antalya pp. 252-256.
38. Yıldırım AN, Tekintaş E, Koyuncu F (2007) The selection of late flowering and high fruit quality almond (Prunus amygdalus Batsch.) genotypes in Isparta province. ADU J Agric Fac 4: 39-48.
39. Acar S, Kazankaya A, Doğan A (2018) Selection of almonds ( amygdalus L.) naturally grown in Eğil and Ergani towns in Diyarbakır province. YYU J Agric Sci 28(4): 448-457.
40. Grassely C (1994) Almond breeding in different countries. Nucis 2: 2-3.
41. Comas JF, Company RS, Segura JMA (2019) Shell hardness in almond: Cracking load and kernel percentage. Sci Horticult 245: 7-11.
42. Uzun A, Akçalı E (2016) Assessment of fruit and some biochemical characteristics of almond genotypes selected from natural populations of Kayseri province. Int J Sec Metabolite 3(2): 82-87.
43. Sümbül A, Bayazit S (2019) Pomological and chemical attributes of almond genotypes selected from Hatay province. Int J Agric Wildlife Sci 5(1): 1-10.
44. Polat Y, Kazankaya A (2020) Fruit features of some almond (Prunus amygladus) genotypes selected from Şanlıurfa region. YYU J Agr Sci 30(2): 328-337.
45. Okie WR (2000) Register of New Fruit and Nut Varieties List 40. Hort Sci 35(5): 812-813.
46. Asensio MC, Socias Company R (1996) Double kernel in almond: An open question. Nucis 5: 8-9.
47. Socias I Company R (1996) Quantitative traits in almond fruits. Nucis 7: 12-14.
48. Alkan G, Tekintaş FE, Seferoğlu HG, Ertan E (2014) Selection of almonds of Niğde Altunhisar region. Turk J Agric Sci Tech 2(1): 51-55.
49. Kodad O, Socias I Company RS (2006) Influence of genotype, year and type of fruiting branches on the productive behavior of almond. Sci Horticult 109(3): 297-302.