The infl uences of thermal effects and salinization on visible and near-IR refl ection spectra of horticultural plant leaves with different drought and salt resistance are examined. An integral criterion for evaluating the susceptibility of the plants to stressors is based on measuring the distance between refl ectance curves.Refl ectance spectroscopy of photosynthetic tissues is one of the most promising non-destructive methods for diagnosing the physiological condition of plants and their resistance to destabilizing effects. Leaves are known to make up the principal refl ecting surface of plants. The refl ectance of a leaf is conditioned by the pigment concentration, tissue structure, water content, and age [1][2][3][4][5][6]. Spectral curves characterizing leaf refl ection coeffi cients (RC) are the integral product of genetic effects and environmental factors [7,8]. The spectral characteristics of visible and IR refl ections can be used to diagnose stress effects, e.g., drought, high temperatures, UV radiation, heavy metals, mineral defi cits, and pests [2,[8][9][10][11][12][13][14][15][16]. However, this method was reported to have limited sensitivity for studying trees because of the considerable variability of the RC depending on the selected photosynthetic organs [17,18]. It was noted [19] that results from many investigations did not achieve the accuracy required for practical use in agriculture.A series of coeffi cients (vegetation indices) calculated from the ratio or difference of RC in certain spectral ranges was proposed to fi nd differences in the refl ectivity of plants [6,[20][21][22][23][24][25][26][27][28]. These coeffi cients are very often associated with pigment content and activity or water content in the plant. Other methods are used to interpret the spectral curves, e.g., calculation of the slope of the electromagnetic spectrum in a certain region [8,29] and subtraction of spectra [30]. Most research was carried out on fi eld or forest cultures. Information on horticultural plants is limited.The present work proposes a spectroscopic model for evaluating the resistance of horticultural plants to drought and salinization that is based on analyses of leaf refl ectance spectra (RS) under varying conditions.The work was performed using the genetic collection at the I. V. Michurin All-Russian Research Institute for Genetics and Breeding of Fruit Plants in 2013-2014. The varieties of horticultural plants used in the work were appeared in the State Registry of Breeding Achievements and included common apricot (Armeniaca vulgaris Lam.), variety Ulyanikhinskii; apple (Malus domestica Borkh.), variety Bylina; plum (Prunus domestica L.), variety Svetlyachok; and black currant (Ribes nigrum L.), variety Ekzotika. The species were selected because of differences in their resistance that were observed in preliminary tests. The plants were cultivated under favorable conditions during the research (July-August) and did not experience destabilizing effects. Undamaged and externally healthy leaves taken fro...

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The research was aimed at evaluating sweet cherry forms on a complex of economically valuable traits and the allocation of promising genotypes for further use in breeding and production. The forms of sweet cherries grow in Michurinsk city of Tambov region. The study of frost resistance was carried out in laboratory conditions. Annual branches were frosted for 12 hours at -32°C and -35°C. Reproductive buds in all studied forms were characterized by reversible damage (less than 3 points) at temperature regime -32°C and complete death at -35°C. 10-117 form was characterized by -35°C frost resistance in the middle of winter, in which the freezing degree of annual branches tissues and vegetative buds did not exceed 2 points. Over the years of research, elites 4/8-24, 10-115, 7-38, 10-117, 6-87, 4/9-15, 7-5 possessed resistance to moniliosis and coccomycosis (the damage degree not more than 2 points). The highest yield (9.75-9.84 t/ha) on average over three years was shown by forms 4/8-24, 7-38, 7-5. Yield at the control level was noted in forms 6-87, 4/9-15, 10-115. Elite forms 4/9-15, 7-38 were characterized by the largest mass of fruits, significantly exceeding the control variety. The average weight amounted to 7.3 and 7.2 g, and the maximum was 9.4 and 8.4 g respectively. Forms 4/8-24, 4/9-15, 7-38 combined the dessert taste of fruits (tasting assessment of 4.6-4.8 points), very juicy and dense pulp.

The gene pool of apple varieties of the Ural-Siberian and Far Eastern group has a valuable genetic potential especially in breeding for winter hardiness. Today, apple breeding research focused on winter hardiness using that varieties is limited. Using in hybridization gene pools created in harsh conditions of Siberia and the Far East will allow promoting the spread of apple culture to the north, which is mainly limited by frost resistance. Assessment of frost damage level of tissues and kidneys of apple shoots by -40°C temperature decrease was the principal goal of the work. According the national food and nutrition security policy, share of fruit production in the northern regions must be increased. In that case, ongoing scientific research has the defining value for these purposes. Different apple tree genotypes responses to low temperatures is highly individual and depends both of the degree or strength of frost and of the sensitivity of the plant itself. This complex interrelationship determinates the winter hardiness level under negative environmental conditions. 30 varieties of apple tree of the Ural-Siberian and Far Eastern groups were selected for study of frost resistance. Genotypes have a sufficient “margin of safety” for resistance to cause by frost damages.

искусственного промораживания и многомерного статистического анализа выявлен общий потенциал зимостойкости более чем у 50 сортов и форм яблони.Проведено ранжирование изученных генотипов по общей степени зимостойкости с учетом основных ее компонентов и физиологической неравноценности повреждаемых тканей, основанное на близости объекта к модели идеального сорта.Ключевые слова: яблоня, сорта, селекция, морозостойкость, компоненты зимостойкости. Summary.Using the methods of artifi cial freezing and multidimensional statistical analysis, the total winter hardiness potential of more than 50 varieties and forms of apple trees has been revealed.The ranking of the genotypes according to the general degree of winter hardiness, taking into account its main components and the physiological disparity of the damaged tissues, was carried out. It was based on the proximity of the object to the model of the ideal variety.