Almonds

Botany, Production and Uses

Rafel Socias i Company, Thomas M Gradziel, Rafel Socias i Company, Thomas M Gradziel

• Publisher: CAB International
• Year: 2017
• Print ISBN: 9781780643540
• eBook ISBN: 9781786392633
• Topic: Biological Sciences
• Subtopic: Horticulture
• Index: Biological Sciences

This book provides a comprehensive overview of almond growing from a scientific and horticultural perspective, covering botany, production, processing and industrial uses. Almonds are an important crop; they are highly regarded for their flavour, nutritional properties and culinary uses, and almond oil is used widely in food, cosmetic and pharmaceutical production. They are easy to transport and have long storability, facilitating global dissemination. Demand is constantly increasing and global production has more than doubled in the last 20 years. The popularity of almonds and the increase in demand has required new plantings and a response to ongoing changes in cultural and climatic conditions. Almonds: Botany, Production and Uses meets the need for up-to-date information on this crop and covers: · botany and taxonomy· cultivation, genetics and breeding· propagation, orchard management and harvesting· pests and diseases· nutrition, marketing and utilization Authored by an international team of experts and presented in full colour throughout, this book is an essential resource for academic researchers and extension workers, as well as growers, orchard managers and industry personnel.

1 Taxonomy, Botany and Physiology

Rafel Socias i Company^*, José M. Ansón and María T. Espiau

Centro de Investigación y Tecnología Agroalimentaria de Aragón, Zaragoza, Spain

^*Corresponding author e-mail: [email protected]

1.1 Almond Taxonomy

Almond belongs to the genus Prunus, which includes all stone fruits, and belongs to the Rosaceae family. Almond is a diploid species with n = 8 (Darlington, 1930), the basic ploidy number of Prunus. In contrast to the other species of this genus, whose commercial interest lies in their juicy flesh or mesocarp, almond is the only Prunus species grown for its seeds, whereas the corky mesocarp is only utilized in animal feeding (Aguilar et al., 1984) or as a manure (Alonso et al., 2012). Thus, almond is often classified more as a nut than as a stone fruit, despite its very close genetic similarities with the other stone fruits, and mainly with peach.

The botanical name of almond has been a subject of diverse controversies and has been changing continuously since Linnaeus began botanical systematics. Although taxonomy aims at unambiguous identification of species, different subjective criteria have led to different classifications, despite the application of objective parameters for species description. Consequently, frequent cases of synonyms for almond and other related species have been – and continue to be – reported. Linnaeus considered Amygdalus as an independent genus, classifying the stone fruits in different genera, corresponding to the main crops: almond (Amygdalus), peach (Persica), cherry (Cerasus), apricot (Armeniaca) and plum (Prunus sensu stricto). This division seems excessive, particularly if the possibilities of hybridization among different stone fruit species are considered. At present, most of these groups are considered subgenera of the genus Prunus, a single genus including all the stone fruit tree species, as the genus Prunus sensu lato.

According to Linnaeus’ criteria, under which the taxa well known to him were excessively subdivided, almond was designated as Amygdalus communis L. (1753, Sp. Pl. 1: 473). This same denomination was also adopted by A.A. von Bunge as A. communis Bunge (1833, Enum. Pl. Chin. Bor. 21), although this name is invalid because it is recurrent. The first change was made by P. Miller, who adopted the denomination A. dulcis Mill. (1768, Gard. Dict., ed. 8. n. 2), without taking into account the presence of bitter kernels in almond and of sweet kernels in other Prunus species, thus making the dulcis designation equivocal.

The first inclusion of almond in the genus Prunus was made by A.J.G.K. Batsch with the denomination P. amygdalus Batsch (1801, Beytr. Entw. Gewächsreich 1: 30). This name was widely accepted for a long time and was also adopted by J.S. Stokes as P. amygdalus Stokes (1812, Bot. Mat. Med. 3: 101), although this is also an invalid name because of recurrence. H.G.L. Reichenbach recovered the wrong denomination of dulcis, but in the genus Prunus under the name P. dulcis (Mill.) Rchb. (1832, Fl. Germ. Excurs. 644), a denomination reactivated more than a century later by D.A. Webb as P. dulcis (Mill.) D.A. Webb (1967, Feddes Repert. 74: 24). Finally, another illegal denomination was proposed by G. Arcangeli as P. communis (L.) Arcang. (1882, Comp. Fl. Ital. 209).

The same diversity of names, mainly due to consideration of whether or not Amygdalus is a genus or a subgenus, is found for the wild species related to almond (Grasselly, 1976; Browicz and Zohary, 1996). The most rational classification is that of Rehder (1940), which considered Amygdalus (L.) Focke as a subgenus under the genus Prunus L., although this classification was not fully adopted. Browicz and Zohary (1996) proposed a classification of the species related to almond considering Amygdalus as a genus. Subsequently, Socias i Company (1998) proposed a classification of all almond species under the subgenus Amygdalus (Box 1.1). Unity of the genus Prunus has been confirmed at the molecular level by the Genome Database for Rosaceae (2016) and the synteny of traits among all species (Arús et al., 2006).

Box 1.1. Classification of almond species (Socias i Company, 1998)

Genus: Prunus L. (1735)

Subgenus: Amygdalus (L.) Focke

Series: Icosandrae Spach (1843)
(Syn.: Subgen. Amygdalus Browicz et Zohary)

(i) Section: Euamygdalus Spach (1843)
(Syn.: Sect. Amygdalus Browicz et Zohary)

Group Amygdalus

1. P. amygdalus Batsch (1801)
(Syn.: A. communis L., A. dulcis Mill., P. communis (L.) Arcang., P. dulcis (Mill.) D.A. Webb). It includes P. korshinskyi Hand.-Mazz.)

2. P. trichamygdalus Hand.-Mazz. (1913)
(Syn.: A. trichamygdalus (Hand.-Mazz.) Woronow)

3. P. fenzliana Fritsch (1892)
(Syn.: A. fenzliana (Fritsch) Lipsky)

4. P. webbii (Spach) Vierh. (1915)
(Syn.: A. webbii Spach, A. salicifolia Boiss. et Bal.)

5. P. haussknechtii C. Schneider (1905)
(Syn.: A. haussknechtii (C. Schneider) Bornm.)

6. P. zabulica (Seraf.) SIC, comb. nov. (1998)
(Syn.: A. zabulica Seraf.). It includes A. browiczii Freitag)

7. P. kuramica (Korsh.) Kitam. (1960)
(Syn.: A. kuramica Korsh.)

8. P. bucharica (Korsh.) Hand.-Mazz. (1913)
(Syn.: A. bucharica Korsh.)

9. P. tangutica (Batal.) Koehne (1912)
(Syn.: A. tangutica (Batal.) Korsh.)

Group Orientalis

10. P. argentea (Lam.) Rehd. (1922)
(Syn.: A. orientalis Duhamel, A. argentea Lam.)

11. P. discolor (Spach) C. Schneider (1905)
(Syn.: A. graeca Lindl., A. discolor (Spach) Roemer)

12. P. elaeagnifolia (Spach) E. Murray (1969)
(Syn.: A. elaeagnifolia Spach, A. kermanensis Bornm.)

13. P. kotschyi (Boiss. et Hohen.) Náb. (1923)
(Syn.: A. kotschyi Boiss. et Hohen.)

14. P. carduchorum (Bornm.) Meikle (1965)
(Syn.: A. carduchorum Bornm.)

15. P. mongolica Maxim. (1879)
(Syn.: A. mongolica (Maxim.) Ricker)

(ii) Section: Chamaeamygdalus Spach (1843)

16. P. nana (L.) Stokes (1812)
(Syn.: A. nana L., P. tenella Batsch). It includes P. georgica (Desf.) and

P. ledebouriana (Schlecht.)

17. P. petunnikovii (Litv.) Rehd. (1926)
(Syn.: A. petunnikovii Litv.)

(iii) Section: Spartioides Spach (1843)

18. P. arabica (Olivier) Meikle (1967)
(Syn.: A. arabica Olivier, A. spartioides Spach, P. spartioides

(Spach) C. Schneider)

19. P. scoparia (Spach) C. Schneider (1905)
(Syn.: A. scoparia Spach)

Series: Dodecandra Spach (1843)
(Syn.: Lycioides Spach)

20. P. lycioides (Spach) C. Schneider (1906)
(Syn.: A. lycioides Spach)

21. P. spinosissima (Bge.) Franch. (1883)
(Syn.: A. spinosissima Bge.)

22. P. eburnea (Spach) Aitch. et Hemsley (1886)
(Syn.: A. eburnea Spach, A. spathulata Boiss.)

23. P. brahuica (Boiss.) Aitch. et Hemsley (1886)
(Syn.: A. brahuica Boiss.)

24. P. erioclada (Born.) SIC, comb. nov. (1998)
(Syn.: A. erioclada Born.)

The following species are considered peach species but also belong to the section Euamygdalus:

P. persica (L.) Batsch (1801)
(Syn.: A. persica L., Persica vulgaris Mill.). It includes P. compressa
(Loud.) Bean (Syn.: Persica platycarpa Dcne., P. vulgaris compressa Loud, P. persica platycarpa Bailey)

P. davidiana (Carr.) Franch. (1872)
(Syn.: Persica davidiana Carr.)

P. mira Koehne (1910)
(Syn.: A. mira (Koehne) Rickter)

P. fasciculata (Torr.) Gray (1874)
(Syn.: Emplectocladus fasciculata Torr., A. fasciculata Greene)

P. kansuensis Rehd. (1922)
(Syn.: A. kansuensis Skeele)

P. pedunculata (Pall.) Maxim. (1883)
(Syn.: A. pedunculata Pall., A. boissieri Carr.)

P. triloba Lindl. (1857)
(Syn.: P. ulmifolia Franch., A. lindleyi Carr., Amygdalus triloba Rickter)

The most recent phylogenetic studies consider that all almond and peach species must be considered as forming the subgenus Amygdalus of the genus Prunus (Yazbek and Oh, 2013), despite the preference of some botanists to maintain Amygdalus as a genus, mostly based on morphological traits and the inconsistency of considering mesocarp dehiscence as a differential trait (Zohary, 1998).

1.2 Wild Almond Species

The interest in wild almond species emerged in the 19th century and was pursued mainly by botanists (Grasselly, 1976). However, observation of the diversity of f...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• About the Editors
• Contributors
• Preface
• Dedications
• 1 Taxonomy, Botany and Physiology
• 2 History of Cultivation
• 3 Production and Growing Regions
• 4 Almond in the Southern Hemisphere
• 5 Classical Genetics and Breeding
• 6 Molecular Breeding and Genomics
• 7 Late-blooming Cultivar Development
• 8 Pollen–Style (In)compatibility: Development of Autogamous Cultivars
• 9 Rootstock Development
• 10 Propagation Techniques
• 11 Orchard Management
• 12 Environmental Requirements
• 13 Almond Water Requirements
• 14 Almond Tree Nutrition
• 15 Almond Diseases
• 16 Almond Pests
• 17 Almond Harvesting
• 18 Chemical Composition of Almond Nuts
• 19 World Almond Market
• 20 Processing and Industrialization
• Index
• Back Cover