Molecular Breeding and Nutritional Aspects of Buckwheat

Meiliang Zhou, Ivan Kreft, Sun-Hee Woo, Nikhil Chrungoo, Gunilla Wieslander

• Publisher: Academic Press
• Year: 2016
• ISBN:
  9780128037140
• Topic: Tecnologia e ingegneria
• Subtopic: Agronomia

Molecular Breeding and Nutritional Aspects of Buckwheat describes the general characterization and genetic diversity of buckwheat (family Polygonaceae, genus Fagopyrum) around the globe (especially in Russia, China, India, and Eastern Europe), the arid and cool regions where it is most frequently consumed, and nutritional information on a variety of buckwheat uses, including tea, groats, flour, and noodles.

With detailed information on buckwheat regeneration, genetic transformation, gene function analysis, and the metabolic engineering of bioactive compounds, the book guides readers through a variety of buckwheat varietal adaptations, providing foundation information on which additional research should be conducted.

It is divided into four parts, including genetic resource and phylogenetic relationship, food nutrition, growth and cultivation, and molecular breeding, with each section providing insights into the most current developments.

• Addresses all aspects of buckwheat research, including genetic resources, biological nutrition, genetic transformation, and molecular breeding
• Presents global characterization on the genetic resource of Fagopyrum, giving researchers insights that will help them breed new cultivars
• Explores the bioactivity of buckwheat
• Includes detailed information on the environmental factors that affect the growth and production of buckwheat

Chapter one

Molecular Taxonomy of the Genus Fagopyrum

O. Ohnishi Plant Germ-Plasm Institute, Graduate School of Agriculture, Kyoto University, Mozume-cho, Muko City, Japan

Abstract

Morphological classification of Fagopyrum is very difficult; in particular, in the species belonging to the urophyllum group of Fagopyrum. In this review I will show how agreeably molecular taxonomy resolved difficult issues in taxonomy and phylogeny in the genus Fagopyrum. The review is focused on (1) two groups of the genus Fagopyrum, the cymosum group and the urophyllum group; (2) controversial opinions on the issue that Fagopyrum cymosum is close to common buckwheat or close to Tartary buckwheat; (3) difficulty in morphological classification of the species in the urophyllum group; (4) examples of the cases of species that are morphologically similar but distinct at the molecular level, and vice versa; and (5) how the classification of diploid and tetraploid plants should be done in the cymosum group and in the urophyllum group of Fagopyrum.

Keywords

cymosum group

molecular taxonomy

phylogenetic relationship

urophyllum group

Introduction

When Steward (1930) classified buckwheat species he recognized two cultivated species, Fagopyrum esculentum and Fagopyrum tataricum, and eight wild species. At that time he classified buckwheat species into a section of the genus Polygonum in a broad sense. However, most taxonomists later treated buckwheat species as the species of a distinct genus Fagopyrum, based on chromosome number (Munshi and Javeid, 1986), and based on pollen morphology (Hedberg, 1946). In the 1990s I and my students found a new species of the genus Fagopyrum in southern China, including the wild ancestor of cultivated common buckwheat, and tried to classify the new species and already known species (Ohnishi, 1990, 1998a; Ohnishi and Matsuoka, 1996; Yasui and Ohnishi, 1998a,b; Ohsako and Ohnishi, 1998, 2000; Ohsako et al., 2002). First, we tried a morphological classification. However, we immediately faced difficulty in finding key character(s) separating different groups of species or different species. For example, at that time it was very suspicious that common buckwheat was closely related to perennial buckwheat, Fagopyrum cymosum. Molecular taxonomic study already suggested that Tartary buckwheat, rather than common buckwheat is more closely related to F. cymosum (Kishima et al., 1995). But what character(s) does separate common buckwheat from the F. cymosum-Tartary buckwheat group? It was a very hard task to find such a character. For more unfamiliar wild species or groups of wild species, classification by morphological characters is much more difficult.

On the other hand, classification by molecular markers has been difficult in mastering the technique of treating target DNAs. However, the results on phylogeny are reasonable in the sense that all the results by different scientists on either chloroplast DNA (cpDNA) or nuclear DNA do not differ by much (compare the results of Ohnishi and Matsuoka, 1996; Yasui and Ohnishi, 1998a,b; Ohsako and Ohnishi, 1998, 2000, 2001; but also see Nishimoto et al., 2003 for the incongruence between nuclear and chloroplast DNA trees).

Molecular classification, however, has such weak points that it cannot be practiced in fieldwork, and getting results takes time. Hence morphological classification should be of primary important in such field research as finding a new species. Molecular classification is much more reliable for phylogenetic analyses; hence we should use the molecular classification for confirming new species or new group(s) of wild species.

In this review, I will show that how agreeably molecular classification solved phylogenetic issues in taxonomy of the genus Fagopyrum.

Two Groups of the Genus Fagopyrum: The Cymosum Group a...