Kiwifruit

The Genus ACTINIDIA

Hongwen Huang

• Publisher: Academic Press
• Year: 2016
• ISBN:
  9780128030677
• Topic: Biological Sciences
• Subtopic: Horticulture
• Index: Biological Sciences

Kiwifruit: The Genus ACTINIDIA includes extensive and full coverage of scientific and applied information, ranging from basic taxonomy, population genetics, and natural resources/distribution, to domestication history and breeding/cultivars, also including further information on culture and international production and commercialization.

The book gathers information not previously available in the English language, providing an authoritative reference for professionals, including taxonomists, horticulturist, breeders, conservationists, kiwifruit technicians, college teachers, policymakers in the industry, and governments. In addition to those in the academic and professional sectors, horticultural and botanical enthusiasts will find the information presented highly accessible.

• Presents the first world monograph on the genus Actinidia (kiwifruit)
• Provides up-to-date research based on "everything kiwi", including new and critical information on kiwi germplasm and taxonomy from China, the native country of kiwi
• Includes authoritative and detailed descriptions for each species, with extensive color illustrations and information accumulated during the author's 30 years of research

Chapter 1

Systematics and Genetic Variation of Actinidia

Abstract

Since the earliest taxonomic treatment suggested by Gilg in 1893, three major revisions have been made by Dunn in 1911, Li in 1952, and Liang in 1984, until the most recent and systematic revision by Li et al. in 2007 with treatment of 54 species and 21 varieties, i.e. 75 taxa in total in Actinidia. Some taxa are anomalous because insufficient attention has been given to interspecific hybrids. More comprehensive fieldwork is required to determine whether all the species so far described are sufficiently distinct to justify separation at the specific level or whether it is more useful to revert to broader species concepts.

Actinidia species have been described as rediploidized palaeopolyploids having a high basic chromosome number (x = 29) and wide variation in ploidy. The timing of the most recent paleopolyploidization event, Ad-α (approx. 28.3 mya), is consistent with this duplication being limited to the Actinidiaceae while the older event Ad-β (approx. 75.9 mya) is shared by the common ancestor of Camellia and Actinidia, and the oldest At-γ occurred at the basal Rosid ancestry.

Currently ecological separation and gene flow dynamics within and between taxa would account for regional clustering of taxa due to combined effects of recurrent polyploidization, and frequent hybridization between geographically overlapping species would result in the reticulate evolutionary structure and many phenotypically transitional forms in the genus. Frequent hybridization in the evolutionary history of many Actinidia taxa is supported by several lines of research evidences, including molecular biology. The biological species concept might be appropriate for most of the currently described Actinidia taxa. The species barriers in the genus seem porous and there appears to have been extensive intra- and interspecific hybridization.

All Actinidia taxa are functionally dioecious. The sex determination studied approves to be of the active-Y type, i.e. male heterogametic X_nX/X_nY, such as in hexaploids the females XXXXXX and the males XXXXXY. Dioecism is not absolute, and flowers can vary in sex expression.

Ploidy races and interploidy hybridization are a phenomenon in Actinidia. Intrataxon ploidy variation has so far been detected in at least 13 Actinidia taxa while intertaxon ploidy variation has been detected in 15 taxa. The complexity due to ploidy races and interploidy hybridization has been best revealed in the A. chinensis species complex involving a series of ploidy races (2x, 3x, 4x, 5x, 6x, 7x, and 8x). Different ploidy levels coexist within a single population. The diploid and tetraploid cytotypes were mainly in eastern China, the hexaploids more in western China; the diploids occur mainly at lower altitudes, tetraploids at intermediate altitudes, and hexaploids at the highest altitudes. This unique geographic distribution of different polyploids and the complexity of reticulate patterns in Actinidia would make it an ideal model for studying ploidy evolution and ecological evolution in plants.

Frequent intra- and interspecific hybridization and continuous intraspecific ploidy variation occurring in natural hybrid zones of sympatric species should also enable kiwifruit breeders to discover novel or desirable phenotypes of different polyploidy by taking full advantage of ploidy races in nature.

Recently initial resequencing across 15 species have resulted in more than 13,000,000 single nucleotide polymorphisms (SNP), 700 multiple nucleotide polymorphisms, 500,000 insertions (INS), and 300,000 deletions (DEL), respectively. In all, a total of more than 14,000,000 different types of genomic variations have been detected.

Keywords

Taxa; Paleopolypoid; Interspecific hybridization; Functional dioecism; Sex determination; Polyploidy; Reticulate evolution; Ploidy race; Hybrid zone; Sympatric species

1.1 Taxonomic Revision

1.1.1 Actinidia Lindl.

1.1.2 Clematoclethra (Franch.) Maxim.

1.1.3 Saurauia Willdenow

1.2 Treatment of Taxa in the Most Recent Revision of Actinidia

1.2.1 Three Varieties of Actinidia arguta (Siebold & Zuccarini) Planchon ex Miquel

1.2.2 Actinidia melanandra Franchet, Varieties and Synonyms

1.2.3 Actinidia kolomikta (Ruprecht & Maximowicz) Maximowicz

1.2.4 Actinidia tetramera Maximowicz

1.2.5 Actinidia valvata Dunn

1.2.6 Actinidia callosa Lindley and A. umbelloides C.F. Liang

1.2.7 The Actinidia chinensis Planchon Complex

1.2.8 Actinidia eriantha Bentham

1.2.9 Synonomy of Actinidia fortunatii Finet & Gagnepain, A. glaucophylla F. Chun, A. henryi Dunn and A. gracilis C.F. Liang

1.2.10 Actinidia fulvicoma Hance, A. cinerascens C.F. Liang and A. f...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Foreword
• Preface
• Acknowledgments
• Introduction
• Chapter 1: Systematics and Genetic Variation of Actinidia
• Chapter 2: Species
• Chapter 3: Natural Distribution of Genus Actinidia
• Chapter 4: Domestication and Commercialization of Actinidia
• Chapter 5: Biology, Genetic Improvement, and Cultivar Development
• Chapter 6: Main Cultivars in Commercial Production
• Chapter 7: Cultivation and Management
• Chapter 8: Harvest and Storage
• Bibliography
• Index