Сельскохозяйственная биология, 2010, № 3, с. 49-53.

УДК 633.12:631.527:577.164.32

BIOLOGICAL AND SELECTION VALUE OF BUCKWHEAT INITIAL MATERIAL WITH HIGH CONTENT OF RUTIN

A.G. Klykov

In 2002-2007 years in the conditions of Primorskii region the author has studied the buck-wheat variants with high content of rutin, which belong to three species — Fagopyrum esculentum Moench., Fagopyrum tataricum (L.) Gaertn and Fagopyrum cymosum Meissn. It was shown, that rutin content changes in connection with plant coloration. The correlation between rutin content, morphological and economic valuable determinants was revealed.

Key words: buckwheat, rutin, selection, marker, initial material.

The climatic conditions of Primorskii region correspond to an unsustainable farming zone with rain shortage or strong atmospheric drought in the first half of buckwheat vegetation (June-July). During the period of its massive flowering - grain formation (August-September), the heavy rainfalls (up to 120 mm / day) contribute to soaking, lodging and root rot of buckwheat plants.
In this regard, the main direction of breeding work with buckwheat is the creation of locally adapted varieties. This task requires suitable source material with valuable breeding, biological, economic determinants and marker characteristics ensuring a focused and efficient selection.
Adaptive properties of plants are manifested in ontogeny as morphological and anatomical, physiological and biochemical changes (1). Flavonoids - one of lagrest and widespread groups of phenolic compounds, playing an important role in adaptation to adverse environmental conditions; they accelerate biological oxidation, photosynthesis, reproduction, energy metabolism, immunity and other vital functions of plants (2, 3). In buckwheat, this is rutin, which focuses the task of creation the varieties with high content of rutin.
One of the important features of phenolic compounds is their capability to be used as markers in chemotaxonomic studies. Thus, for the family Polygonaceae, the effectiveness of using flavonoids for establishment the phylogenetic relationships of taxa was shown by G.I. Vysotchina (4). Flavonoids are also of interest in relation to the problem of phytoimmunity. Have studied the World Collection of buckwheat (N.I.Vavilov Institute of Plant Industry - VIR, St. Petersburg) for the crop’s resistance to phytopatogens, it has been found that a high content of rutin in leaves can be used as a marker characteristic in breeding for resistance to fungal diseases (5).
In 1970-1980, L.M. Moiseenko assessed rutin content in more than 2000 buckwheat variants (6). Later, the factors influencing rutin accumulation in buckwheat plants were studied: sowing date, micronutrients, fertilizers, biologically active substances, the dynamics of rutin content and the aboveground mass productivity during a growing season, etc. (7). However, there’s pacity of data about the functions of phenolic compounds in plants, in particular, the relation between rutin content and morphological, biological, and economically valuable properties. The medicine importance of rutin (source of antioxidants) should be noted too, as well as its use in food (natural dyestuff) and other sectors of economy.
The purpose of this study - to evaluate the initial material of buckwheat with a high content of rutin upon its breeding and economic determinants, including the connection between rutin content in plants and their morphological and economically valuable characteristics, and to assess the suitability of using plant coloration as a marker of rutin content in breeding practice.
Methods. The research was carried out in the Primorskii region in 2002-2007, upon the buckwheat species with high content of rutin in green phytomass and in grain - Fagopyrum esculentum Moench., F. tataricum (L.) Gaertn and F. cymosum Meissn. F. esculentum was represented by two locally adapted variants - Pri 7, Izumrud and the third variant Primorskaya 356 obtained by competitive selection in Primorskii SRI of Agriculture; F. tataricum – the variant k-62 from Canada, F. cymosum – the variant k-4231 from India.
Annually during 3 years, the buckwheat plants were selected by their color from the variants-populations of Pri-7, Izumrud and Primorskaya 356; 200 plants of each variant were analyzed in 3 replications.

The variants’ assessment was performed on the basis of phenological observations using the state method of crops testing (8). Rutin was identified with 1H NMR-spectra on the spectrometer Bruker AC-250 (250,13 MHz for 1H) (“Bruker”, Germany) in CDCl3 and acetone-d6. Mass-spectra were obtained using the device LKB-9000S (“LKB”, Sweden) with direct input of ionizing electrons’ energy 18 and 70 eV. The content of rutin was determined as described (9).
The experimental data were processed by statistical and correlation analysis proposed by B.A. Dospekhov (10).
 
Results. At present time, almost all the buckwheat varieties and samples of  VIR collection are complex populations with a wide genofund of determinants, particularly, for coloration of stem and branches. The possibility of allocation the forms with different content of rutin has been revealed in the plants from three studied variants-populations (Fig.).
The plants with red-colored stem and branches contain more routine than plants of green, green-red and red-green color. Thus, rutin content in red-colored plants was 26-64% higher than in green ones. The greatest variation of this feature was found in the variant Primorskaya 356 (7,6-12,5 mg / g); such populational polymorphism indicates the prospects for selection of the increased content of rutin.

 
The assessment of main economically valuable characteristics in plants the variant Izumrud (Table 1) has proved that red-colored forms demonstrate the highest content of rutin, as well as some other outstanding properties. They exceed the initial variant Izumrud (standard) in accelerated development, number of lateral branches of the 2-th order, thickness of the 1-st internode, and in number of grains per plant. These facts suggested the development of method for selection the buckwheat plants with high content of rutin in aboveground phytomass by the dark-red coloration of stems and branches during the phase of fruit formation (11).

Productivity of buckwheat varieties and their resistance to lodging under unfavorable growing conditions mainly depend on root providing of an aboveground unit and the intensity of its growth during flowering and fruit formation. In the beginning of buckwheat flowering, 35 - 55% its root surface is inactive, and in the period of massive flowering, 2 / 3 roots are dark colored; when 75% buckwheat grain get brown, all the plant’s roots become dark-brown. In the selection for lodging resistance, it is important to obtain the variety with a powerful root system maintaining its physiological activity till the end of growing season. Have compared the dynamics of accumulation of aboveground and root mass, root providing and rutin content in F. esculentum and F. tataricum (see Table 2), F. tataricum has been found to perform the highest adaptability to the conditions of Primorskii region. In the period of flowering – fruit formation, F. tataricum plants were keeping in their roots 2,6 times more rutin (8 mg / g) and had 1,6 times higher root supply than that of F. esculentum. These data indicate that choosing the initial material for selection of locally adapted buckwheat varieties, one should pay attention to rutin content in roots.
In F. tataricum, a strong positive correlation between the content of rutin in roots, the aboveground and root mass, and root providing has been found (the correlation coefficient for the latter characteristic is somewhat smaller) (see Table 3). These data became the basis for development the method of buckwheat selection for lodging resistance, including three properties - color of root system, root supply and rutin content in roots (12). It has been found, that buckwheat plants with high resistance to lodging (5 points) have a viable root system (light colored) during the phase of fruit formation, root providing – not less than 0,14 and rutin content in roots - not less than 6 mg / g.  

That has been also shown, that rutin content in grain from the cultivated variants F. esculentum is over than 200 times less than that of the wild species F. tataricum (24 mg / g) and F. cymosum (11 mg / g), which indicates the wild buckwheat species as the valuable genetic sources in breeding for a high content of rutin in grain. In F. esculentum (the variants Pri 7 and Izumrud), rutin content in grain amounted to 0,09 and 0,06 mg / g, resp.
The studied variants were distinct in grain color: F. esculentum the variant Izumrud – light-green, F. esculentum the variant Pri 7 – light-brown, F. tataricum and F. cymosum – the pronounced yellow-green. The above results are consistent with the data on the importance of routin in acquisition a fruit color (yellow-green suggests an increased content of rutin) (13). Thus, the color of buckwheat grain can be used as a preliminary marker for visual selection of rutin-rich buckwheat forms and culling of hybrid material.
 Thus, the possibility of using the morphological (color of grain, roots, stem and branches) and chemical (content of rutin) characteristics as markers for the selection of buckwheat forms with a high content of rutin and other economically valuable properties was shown, and the connection between a content of routine, morphological and economically valuable determinants of plants distinct in color has been revealed.

Author thanks the staff of the Tikhookeanskii  Institute of Bioorganic Chemistry RAS for quantitative analysis of samples.

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