Component Of Winter Hardiness Research Articles

Influence of mineral, organic, organomineral fertilization on winter hardiness components of columnar apple tree (<i>Malus domestica</i> Borkh.)

Intensive biological technologies of apple-tree cultivation with application of organic and mineral fertilizers form high nitrogen nutrition, thus leading to prolonged growth of fruit plants and reducing their winter hardiness. Columnar apple tree fail to demonstrate high potential for winter hardiness. Therefore, research into regularities and mechanisms behind the influence of nutritional status of columnar apple tree on indicators of plant winter hardiness is considered relevant. The research was aimed at establishing the influence of mineral, organic, organomineral fertilization on the components of winter hardiness of columnar apple trees grown on podzolic soil. Materials and methods. The research involved the ‘Triumph’, ‘President’, ‘Ostankino’ columnar apple varieties, as well as organic and mineral fertilizers. The experiment was conducted in 2016–2021 in the agrochemical experiment station of the Federal Horticultural Center for Breeding, Agrotechnology and Nursery (Moscow region) on podzolic soil of medium-loam particle size distribution. The experimental design included 4 variants: 1) control without fertilizers; 2) N90K90; 3) organic fertilizers 100 t/ha; 4) N90K90 organic fertilizers 100 t/ha. Naa (ammonium saltpeter), KCl mineral fertilizers were applied annually, organic fertilizer (horse manure with sawdust) was applied in 2014. Winter hardiness components and plant samples were analyzed according to generally accepted methods. According to the research into the influence of mineral, organic, organomineral fertilization on the components of winter hardiness of columnar apple tree (Malus domestica Borkh.) grown on podzolic soil in the conditions of the Moscow region, the fertilizer is found inefficient in terms of providing the optimal level of nitrogen nutrition of columnar apple tree plants, except for ‘Triumph’ variety when getting organic fertilizers at a dose of 100 t/ha. In January, fructose prevailed in the sugars of annual shoots of columnar apple tree plants. The ‘Triumph’ and ‘President’ varieties showed a tendency to increase in the content of fructose and glucose as compared with the control when getting organic fertilizers and their combination with mineral fertilizers. The same tendency was observed in the ‘Ostankino’ variety for the content of ascorbic acid in annual shoots, whereas this indicator of the ‘Triumph’ and ‘President’ varieties demonstrated the opposite trend. The ascorbic acid content in annual shoots in winter appeared consistent with its content in August shoots and remained independent on the content in leaves in August. With a decrease in temperature to -40 °C (component II of winter hardiness), the ‘Triumph ‘and ‘Ostankino’ varieties suffered reversible damage to the vegetative buds from 0 to 2.0 points, the ‘President’ variety introduced with 100 tons/ha organic fertilizers demonstrated an increase in damage to the vegetative buds to 3.17 points. The greatest damage to reproductive buds in the ‘President’ and ‘Ostankino’ varieties (3.85-3.91 on the control) was observed in component II of winter hardiness. The application of mineral and organic fertilizers increased these damages to complete death of reproductive buds. Injuries to bark, cambium in all variants of the studied varieties did not exceed 2.0 points. Wood appeared more damaged in the ‘Ostankino’ variety (up to 4.03 points in the combined application of N90K90 and 100 t/ha of organic fertilizers) as well as in the Triumph variety (up to 3.80 points in the N90K90 variant). As for component III of winter hardiness, an irreversible damage was noted for reproductive buds of the studied varieties in all variants of the experiment. In terms of component IV of winter hardiness, irreversible changes occurred in reproductive buds to the greatest extent (complete death in the ‘Triumph’ and ‘President’ varieties); in the tissue under reproductive buds, to the greatest extent in the ‘President’ variety (3.07 points in the variant of 100 tons/ha of organic fertilizers) and in the ‘Ostankino’ variety (2.76 points in N90K90), at the core, the maximum damage was noted in the N90K90 variant in the ‘Triumph’ (3.22 points) and ‘Ostankino’ (2.76 points) varieties.

Изучение зимостойкости абрикоса в контролируемых условиях

Abstract. The purpose of the research is to study the winter hardiness of apricot cultivars and hybrids and identify the most resistant ones to damaging factors of the winter period for use as sources for a given trait in breeding. Methods. The studies were carried out by artificial freezing using a climate chamber. Results. It was determined that apricot cultivars ‘Abrikos iz Kitaya’, ‘Agafonovskiy’, ‘Vostochno-Sayanskiy’, ‘Kunach’, ‘Lel’’, ‘Oblepikhovyy’, ‘Orlovchanin’, ‘Sardoniks’, ‘Triumf severnyy’ and hybrids 21183, 23659, 23688, 23797, 24071 and 24206 they have the component I of winter hardiness. ‘Orlovchanin’, ‘Triumf severnyy’ and hybrids 24071 and 24206 were characterized by maximum frost resistance (the component II of winter hardiness). ‘Agafonovskiy’, ‘Vostochno-Sayanskiy’, ‘Desertnyy’, ‘Oblepikhovyy’, ‘Triumf severnyy’ and 24206 had the ability to maintain frost resistance when the temperature droped to –17 °C after a three-day thaw of +2 °C (the component III of winter hardiness). It is important to note the average level of frost resistance of generative buds in ‘Abrikos iz Kitaya’, ‘Kunach’, ‘Orlovchanin’, ‘Podarok Vekhovu’, ‘Sardoniks’, ‘Khabarovskiy’ and hybrids 21183, 23659, 23688, 23797, 24071. At the end of winter, ‘Abrikos iz Kitaya’, ‘Agafonovskiy’, ‘Vostochno-Sayanskiy’, ‘Desertnyy’, ‘Oblepikhovyy’, ‘Orlovchanin’, ‘Sardoniks’, ‘Triumf severnyy’, ‘Khabarovskiy’ and hybrids 21183, 23797, 24071, 24206 were able to restore frost resistance at a temperature of –25 °C after a three-day thaw of +2 °C and re-hardening (component IV of winter hardiness). Scientific novelty. As a result of artificial freezing, perspective cultivars ‘Orlovchanin’, ‘Triumf severnyy’ and hybrids 24071, 24206 characterized by the greatest frost resistance potential for the main components of winter hardiness were identified for further use as sources for this trait in breeding.

A comparative assessment of winter hardiness in varieties and elites of domestic apple trees of various breeding in the conditions of the continental climate of the Samara region

The research was carried out in order to assess the winter hardiness of apple varieties of the Oryol and Michurinsky selection, as well as the elite hybrids of the selection of the Scientific Research Institute of Horticulture and Medicinal Plants Zhigulevskie Sady in the conditions of the continental climate characteristic of the Samara region. Freezing of annual branches taken from trees of 1011 years of age was carried out in the laboratory under controlled conditions of a freezer at extreme negative temperatures for the 2nd (40C) and 4th (35C after thaw) components of winter hardiness. After freezing, their damage was assessed in April, the results were compared by years of research. Simultaneously with the assessment of winter hardiness in the laboratory, the general condition of trees of these varieties and elite hybrids was assessed in the field conditions of the experimental garden of the Scientific Research Institute of Horticulture and Medicinal Plants Zhigulevskie Sady, in August 2020 and 2021. The general condition and adaptation to low temperatures of the objects of the study were compared with dependence on the agro-climatic conditions of the growing season on the basis of meteorological data of the Samara GMC. During the study, varieties and elites of apple trees of various breeding with high winter hardiness were identified, surpassing control varieties such as Antonovka obyknovennaya, Kutuzovets, Severniy Sinap and others in this indicator. It is quite logical that winter-hardy apple trees, in the absence of winter damage, may have stronger immunity to diseases and resistance to pests. Therefore, the widespread introduction of new varieties and hybrids into industrial gardening will contribute to the creation of a more favorable agroecological environment in the gardens of the Samara region and the Middle Volga region.

PEAR (PYRUS COMMUNIS L.) GENOTYPES AND THEIR HYBRIDS EVALUATION FOR WINTER HARDINESS IN THE CENTRAL REGION OF RUSSIA

This study comprises the selection of winter-hardy to highly winter-hardy pear (Pyrus Communis L.) hybrid seedlings procured from various genetic origins. The development of pear hybrids resulted from intraspecific, interspecific, and distant hybridization. The simulation of the most damaging factors in the artificial climate chamber ensued according to the second and third components of winter hardiness - maximum frost resistance in a hardened state and stability of resistance to frost during the thaw. Critical temperatures affected the same seedlings, successively applying the specified modes, i.e., hardening at -10°C, freezing at -37°C (12 h), hardening at -10°C, thaw at +2°C (5 days), and freezing at -25°C (12 h). Combining genetically related variants to the highly winter-resistant cultivar, Phorun established the high breeding value for the yield of hybrid seedlings resistant to frost on the 2 + 3 components of winter hardiness. Thus, in the family 17-43-30 (Phorun - free pollination) × Shihan, 5.0% of transgressive genotypes came up, which withstood the given modes without damage to the buds and central tissues, showing 48.3% of highly winter-resistant forms. In a hybrid combination of 24-45-45 (Phorun × Olivier de Serre) × (Gervais + Olivier de Serre + Dekanka Zimnyaya), 33.3% of seedlings with frost resistance at the level of the highly winter-resistant control cultivar Tonkovetka attained selection. Remote hybridization opens up new opportunities in the pears’ selection for frost resistance. In total, and as a result of distant hybridization, 5.47% of the genotypes (with frost resistance for the 2 + 3 components of winter hardiness above Tonkovetka), 18.24% (at the level of Tonkovetka with freezing to 1.0 point), and 20.73% types (at the level of winter-resistant control cultivar Bessemyanka with freezing to 2.0 points) gained distinction.

A study of introduced apple cultivars according to the main components of winter hardiness by simulating damaging factors under controlled conditions

Background. Most of the plantings of fruit crops in Russia are located in the zone of risky agriculture. In the European part of Russia, in winter, fruit crops are affected by the impacts of weather conditions (spring frosts, droughts, early frosts, low-temperature stress, a short growing season, and thaws). Frosts cause 98% of the damage to fruit trees.Methods. One-year-old branches were frozen in a Japanese Espec PSL-2KPH climate chamber after prehardening under –5°C and –10°C for 5 days, and damaging factors of the winter period were simulated.Results. The bioresource collection of the All-Russian Research Institute of Fruit Crop Breeding (VNIISPK) contains 730 appletree cultivars from various domestic and foreign institutions. Apple cultivars from Ukraine, Belarus, Latvia, Moldova, USA, France, Czech Republic, Sweden and Canada were analyzed for frost resistance components. The resistance of plants to early frosts of–25°C without hardening and after hardening in early winter (Component I) showed that the main tissues (bark, cambium and wood) suffered minor damage in all studied cultivars. In cv. ‘Belarusskoye Sladkoye’, the damage to the bark scored 2.3 points. Among the studied apple cultivars whose one-year-old branches were frozen at –38°C and –40°C (Component II), ‘Coremolda’ (Moldova) showed the highest frost resistance to the negative mid-January temperature of –38°C (damage to the buds and main tissues scored 0.3–1.0 points). Under–40°C (Component II), ‘Coremolda’ (Moldova) and ‘Aivaris’ (Latvian breeding) demonstrated bark, cambium and wood resistance with damages at the level of 2.0 points. These cultivars can be used in breeding programs as sources of frost resistance. Freezing of one-year-old branches under –25°C after a 3-day artificial thaw at +2°C revealed bud and tissue resistance in the American cv. ‘Red Free’ and in cv. ‘Coremolda’ (Component III).

Study of Raspberry Genotypes by Biologically Valuable Traits under Conditions of Central Russia

In Central Russia, the area of possible effective use of raspberry varieties and their productivity and production values are determined by the plant tolerance to a complex of adverse environmental factors. In this regard, the introduction of new varieties and hybrids should be accompanied by analyzing not only their productivity, but also their winter hardiness and drought resistance. In this paper, we analyzed the winter hardiness of raspberry varieties and indicators of their water regime in the field. By modeling the damaging factors of the winter period, we revealed the stability potential of raspberry varieties for the main components of winter hardiness. The drought resistance of raspberry varieties and forms were assessed in laboratory conditions. According to the results of the complex studies, we identified the frost-resistant accessions: 9-17, 9-35, and 9-70 (freezing ranged from 1.1 to 2.0 points) as well as the medium-hardy varieties Glen Ample, Glen Magna, and Laszka (freezing score ranged from 2.1 to 3.0 points). The indicators of the water regime in the field showed that during the growing season, the studied raspberry varieties were characterized by optimal hydration and water deficiency of the leaf apparatus. This positively affected the yield formation. When modeling drought, raspberry genotypes showed a medium level of drought resistance. At the same time, the Glen Ample, Glen Magna, Glen Lyon, and Laszka varieties as well as the accession 9-70 showed high yields (above 15 t/ha). As a result, promising raspberry genotypes Glen Ample, Glen Magna, Laszka, and 9-70 were selected for further breeding and production cultivation in Central Russia.

Assessment of the resistance of raspberry varieties and hybrids to abiotic factors for use in breeding

The purpose of the research was to identify genetic sources of resistance to abiotic environmental factors. The assessment of the raspberry source material was carried out in 2017-2021. The study included 40 varieties and 20 hybrid forms of raspberry. It is established that under simulated conditions, the selected form 1-188-1 has high resistance to temperature -35°C in the middle of winter (II component). Sources of resistance to frost -22oC after the thaw (III component) are varieties Ulybka, Meteor and forms 1-15-1, 1-4-2. The varieties Ivan Kupala, Ulybka and selections 1-188-1, 1-4-2, 6-125-4, 8-10x-1 with freezing up to 1.6-2.1 points were distinguished by the greatest resistance of the buds for the IV component of winter hardiness. The Penguin, Yubileynaya Kulikova varieties and selections 8-189-1, 3-40-14, 44-154-2, 1-180-2 with full ripening of the crop and a relatively short fruiting period (48-55 days) are of interest for further breeding for early ripening of the primocane raspberry. In breeding for high drought and heat resistance, the varieties Gusar, Ulybka, Poklon Kazakovu, Medvezhonok, Gerakl and selected forms 37-143-3, 11-107-1 are promising, combining several indicators of the water regime at the optimal level.

Changes in Ethylene, ABA and Sugars Regulate Freezing Tolerance under Low-Temperature Waterlogging in Lolium perenne.

Plant overwintering may be affected in the future by climate change. Low-temperature waterlogging, associated with a predicted increase in rainfall during autumn and winter, can affect freezing tolerance, which is the main component of winter hardiness. The aim of this study was to elucidate the mechanism of change in freezing tolerance caused by low-temperature waterlogging in Lolium perenne, a cool-season grass that is well adapted to a cold climate. The work included: (i) a freezing tolerance test (plant regrowth after freezing); (ii) analysis of plant phytohormones production (abscisic acid [ABA] content and ethylene emission); (iii) measurement of leaf water content and stomatal conductance; (iv) carbohydrate analysis; and (v) analysis of Aco1, ABF2, and FT1 transcript accumulation. Freezing tolerance may be improved as a result of cold waterlogging. The mechanism of this change is reliant on multifaceted actions of phytohormones and carbohydrates, whereas ethylene may counteract ABA signaling. The regulation of senescence processes triggered by concerted action of phytohormones and glucose signaling may be an essential component of this mechanism.

Study of frost resistance and drought resistance of apple tree varieties of VNIISPK breeding on clonal rootstock 54–118

Apple tree varieties on clonal rootstock 54–118 were studied in terms of frost resistance and drought resistance. The purpose of the research is to study the resistance to frost and drought of apple tree varieties of VNIISPK breeding on clonal rootstock 54–118. Climatic conditions affect fruit trees and further lead to a sharp decrease in the fruit productivity and commercial qualities. The problem study of resistance to various extreme growing conditions (including frost, low temperatures, drought and high temperatures) is relevant. A variety that has a high resistance under various adverse weather conditions is considered as winter-hardy, i.e. shows all the components of frost resistance. The study of the main components of winter hardiness (I, III, IV) showed that apple tree varieties (Orlik, Venyaminovskoye, Sinap Orlovsky, Veteran, Svezhest, Rozhdestvenskoye, Bolotovskoye - of the FSBSI VNIISPK breeding; Antonovka obyknovennaya - of local selection on clonal rootstock 54–118) had minor bud damage. The bark and wood were not damaged. When studying the total water content of leaf tissues during the growing season, all varieties on the clonal rootstock 54–118 were assigned to the average level of hydration. In laboratory conditions, over the years of research, the varieties had a high indicator of the ability to restore water content of leaf tissues after drought. On the clonal rootstock 54–118 the apple tree varieties are able to withstand thaws, spring frosts, droughts and dry winds.

Study of maximum frost resistance of cherry scion/stock combinations

The research was carried out on the basis of the laboratory of stability of physiology of fruit plants at All-Russian research Institute of Breeding of Fruit Crops in 2017-2018. The object of research was the scion/stock combinations of Novella and Turgenevka cherries/82987, C-2-180, 74332, 74340, 74336, 74324 breeding of the Institute. In the study of winter hardiness of cherry, special attention was paid to the ability of varieties to withstand low temperatures in mid-winter. The aim of the research was to study the maximum frost new scion/stock combinations of cherries by artificial freezing and selection of the hardiest of them. The results of the research noted that in the recovery period of organic dormancy in late December, when the cherry plants acquire the maximum hardened state, study scion/stock combinations were characterized by high resistance to frost of bark and wood of annual branches. They noted frost resistance of vegetative buds with reversible damage. Significant differences in the freezing vegetative buds, bark and wood between scion/stock combinations of sweet cherries are shown. Novella and Turgenevka cherry varieties on clonal rootstocks 74332, 74336, characterized by the greatest potential frost resistance of vegetative buds and tissues of annual branches at lower t= -35°C (winter hardiness component II) at the end of December. It is shown that all cherry scion/stock combinations have a low potential frost resistance of generative buds. After exposure to t= -35°C, living rudiments of flower buds preserved only in cherry scion/stock combinations Novella/74332, Turgenevka/74340, 74336 (from 4.0 to 15.4 %). According to the results of artificial freezing scion/stock combination Novella/74332 and Turgenevka / 74332, 74336 were revealed, which were characterized by the maximum frost resistance of generative, vegetative buds, bark and wood.

Resistance of Raspberry Cultivars to Temperature Stress Factors during the Winter Period

The paper presents the results of studies on the winter hardiness of raspberry cultivars and selected forms in field and laboratory conditions, which were conducted at the All-Russia Horticultural Institute for Breeding, Agrotechnology, and Nursery and its Kokino base station (Bryansk oblast). The objects of studies were 20 cultivars and ten selected forms of raspberry of various genetic and geographical origin. The main goal of the work was to study the resistance of raspberry cultivars and selected forms to temperature stressors of the winter period and to reveal the most winter-hardy genotypes. High winter hardiness was revealed for the Peresvet, Balzam, Beglyanka, and Rubin Bryansky cultivars and nine selected forms. The modeling of damaging winter factors revealed that the Gusar, Lazarevskaya, Volnitsa, and Meteor cultivars and selected forms 32-16-1, 1-15-1, 1-2-2, and 6-12-2 tolerated well a frost of –35°C in the middle of winter. Reliable resistance to a III winter hardiness component is featured by the Gusar, Meteor, and Volnitsa cultivars and selected forms 32-16-1, 1-4-2, 1-15-1, 1-2-2, and 2-12-1. Among the studied raspberry assortment, the genotypes with a high level of bud resistance to IV winter hardiness component were not revealed.

Resistance of raspberry caltivars to temperature stress factors of the winter period

The results of researches of winter hardiness cultivars and selected forms of raspberry in the field and laboratory conditions have been presented. The study was conducted in FSBSI All-Russia STIHNG and its Kokino Base Station (Bryansk region). The objects of research were 20 cultivars and 10 selected forms of raspberry of various genetic-geographical origin. The main purpose of the work was to study the resistance of cultivars and selected forms of raspberry to temperature stress factors of the winter period and the identification of the most winter-hardy genotypes. As a result, it was established that the cultivars Peresvet, Balzam, Beglyanka, Rubin Bryanski and nine selected forms showed high field winter hardiness. When modeling damaging winter factors, it was revealed, that the cultivars Gusar, Lazarevskaya, Volnitsa, Meteor and selected forms 32-16-1, 1-15-1, 1-2-2, 6-12-2 well tolerated frost-35C in the middle of winter. The cultivars Gusar, Meteor, Volnitsa and selected forms 32-16-1, 1-4-2, 1-15-1, 1-2-2, 2-12-1 distinguished by reliable resistance to component III of winter hardiness. Among the studied raspberry assortment, the genotypes with a high level of bud resistance to IV component of winter hardiness were not revealed.

Insight into cellular proteome of Lolium multiflorum/Festuca arundinacea introgression forms to decipher crucial mechanisms of cold acclimation in forage grasses

Frost tolerance is the main component of winter-hardiness. To express this trait, plants sense low temperature, and respond by activating the process of cold acclimation. The molecular mechanisms of this acclimation have not been fully understood in the agronomically important group of forage grasses, including Lolium-Festuca species. Herein, the introgression forms of L. multiflorum/F. arundinacea distinct with respect to their frost tolerance, were used as models for the comprehensive, proteomic and physiological, research to recognize the crucial components of cold acclimation in forage grasses. The obtained results stressed the importance of photosynthetic performance under acclimation to low temperature. The stable level of photochemical processes after three weeks of cold acclimation in the introgression form with a higher level of frost tolerance, combined simultaneously with only slightly (but not significantly) decreased level of CO2 assimilation after that period, despite significantly lower stomatal conductance, indicated the capacity for that form to acclimate its photosynthesis to low temperature. This phenomenon was driven by the Calvin cycle efficiency, associated with revealed here accumulation profiles and activities of chloroplastic aldolase. The capacity to acclimate the photosynthetic machinery to cold could be one of the most crucial components of forage grass metabolism to improve frost tolerance.

The relationship among freezing tolerance, vernalization requirement, Ppd alleles and winter hardiness in European wheat cultivars

SUMMARYWinter hardiness of wheat is a complex trait involving a system of structural, regulatory and developmental genes, which interact in a complex pathway. The objective of the present work was to study the relationship among the main traits determining the level of adaptation and the possibility for target manipulation of breeding material by using molecular markers and phenological parameters. Wheat cultivars from different ecoclimatic environments of Europe were included for analysis. Gene-specific assay showed that photoperiod sensitivity of the studied cultivars was determined by polymorphism in the Ppd-D1 allele. The study established the relationship among winter hardiness, LT50 (the temperature at which 50% of plants are killed), photoperiod sensitivity, vernalization duration and earliness per se genes in the environment of Lithuania. The cultivars from Northern and Western Europe exhibited stronger requirement for vernalization and photoperiod. Although the group of cultivars from the southern latitudes were characterized by earliness, they possessed a stronger level of LT50. The level of LT50 was found to be the most crucial component of winter hardiness, the other traits served as supplementary components.

ОЦЕНКА УСТОЙЧИВОСТИ ИНТРОДУЦИРУЕМЫХ СОРТОВ VACCINIUM × COVILLEANUM BUT. ET PL. (ERICACEAE) ПО ВТОРОМУ И ЧЕТВЕРТОМУ КОМПОНЕНТАМ ЗИМОСТОЙКОСТИ В УСЛОВИЯХ БЕЛОРУССКОГО ПОЛЕСЬЯ

The frost resistance of six varieties of northern highbush blueberry (early-ripening - ‘Bluetta’, ‘Spartan’, mid-season - ‘Bluecrop’, ‘Toro’, late-ripening - ‘Elizabeth’, ‘Elliott’) has been studied in the condition of Polesie (southern agro climatic region of the Republic of Belarus) during 2012-2014. It was revealed that late-ripening varieties display lower frost-resistance than early and mid-season varieties on the second and fourth components of winter hardiness.

Copy number variations of CBF genes at the Fr‐A2 locus are essential components of winter hardiness in wheat

Winter hardiness is important for the adaptation of wheat to the harsh winter conditions in temperate regions and is thus also an important breeding goal. Here, we employed a panel of 407 European winter wheat cultivars to dissect the genetic architecture of winter hardiness. We show that copy number variation (CNV) of CBF (C-repeat Binding Factor) genes at the Fr-A2 locus is the essential component for winter survival, with CBF-A14 CNV being the most likely causal polymorphism, accounting for 24.3% of the genotypic variance. Genome-wide association mapping identified several markers in the Fr-A2 chromosomal region, which even after accounting for the effects of CBF-A14 copy number explained approximately 15% of the genotypic variance. This suggests that additional, as yet undiscovered, polymorphisms are present at the Fr-A2 locus. Furthermore, CNV of Vrn-A1 explained an additional 3.0% of the genotypic variance. The allele frequencies of all loci associated with winter hardiness were found to show geographic patterns consistent with their role in adaptation. Collectively, our results from the candidate gene analysis, association mapping and genome-wide prediction show that winter hardiness in wheat is a quantitative trait, but with a major contribution of the Fr-A2 locus.

Frost hardiness of introduced sea buckthorn (Hippophae rhamnoides L.) genotypes in Central Russia

Abstract Sea buckthorn (Hippophae rhamnoides L.) genotypes of different ecological and geographical origins were tested. Frost hardiness extent was determined during winter by artificial freezing, which allowed identify varietal differences in frost hardiness of buds and tissues of sea buckthorn shoots. In order to identify differences in adaptation to low temperature we determined the fractional composition of water in annual shoots; and proline and malone dialdehyde concentration and total amylase activity in bark of shoots of female and male genotypes. In December, the sea buckthorn genotypes were in deep dormancy, when maximum frost hardiness of buds and tissues of annual shoots occurred. During the next months, the frost hardiness of buds and shoot tissues decreased during the state of exogenous dormancy. The performed experiment gave an opportunity to select hardy genotypes ‘Kenigsbergskaya’, ‘Surpriz Baltiki’, B 23-34, and ‘Prima Dona’ for use in further breeding, as they had demonstrated stable hardiness during the whole winter period according to all of the components of winter hardiness.

Allelic variation at Fr-H1/Vrn-H1 and Fr-H2 loci is the main determinant of frost tolerance in spring barley

Frost tolerance is the main component of winter hardiness for cereals and is largely dependent on the plant's ability to cold acclimate by means of a slow adaptive response induced by low, non-freezing temperatures. In the present work, a Genome-Wide Association mapping study has been performed, looking for the genetic determinants of frost tolerance in a panel of European spring 2-row barley cultivars. Frost damage was evaluated by measuring chlorophyll fluorescence (Fv/Fm) and membrane integrity (Electrolyte Leakage) and considerable variation for this trait was discovered. Genetic association of the trait was sought with >5000 gene-based mapped SNP markers using a Mixed Linear Model approach. A simple genetic architecture was revealed for frost tolerance in this population, with a principal role for the Fr-H1/Vrn-H1 and Fr-H2 loci already detected in previous linkage and association mapping studies. Allelic richness might exist at these loci, not only between winter and spring barley, but also within the spring germplasm, thus offering the opportunity for future development of new spring barley lines with improved resilience in the face of emerging climate change.

Genome-wide association mapping of frost tolerance in barley (Hordeum vulgare L.)

BackgroundFrost tolerance is a key trait with economic and agronomic importance in barley because it is a major component of winter hardiness, and therefore limits the geographical distribution of the crop and the effective transfer of quality traits between spring and winter crop types. Three main frost tolerance QTL (Fr-H1, Fr-H2 and Fr-H3) have been identified from bi-parental genetic mapping but it can be argued that those mapping populations only capture a portion of the genetic diversity of the species. A genetically broad dataset consisting of 184 genotypes, representative of the barley gene pool cultivated in the Mediterranean basin over an extended time period, was genotyped with 1536 SNP markers. Frost tolerance phenotype scores were collected from two trial sites, Foradada (Spain) and Fiorenzuola (Italy) and combined with the genotypic data in genome wide association analyses (GWAS) using Eigenstrat and kinship approaches to account for population structure.ResultsGWAS analyses identified twelve and seven positive SNP associations at Foradada and Fiorenzuola, respectively, using Eigenstrat and six and four, respectively, using kinship. Linkage disequilibrium analyses of the significant SNP associations showed they are genetically independent. In the kinship analysis, two of the significant SNP associations were tightly linked to the Fr-H2 and HvBmy loci on chromosomes 5H and 4HL, respectively. The other significant kinship associations were located in genomic regions that have not previously been associated with cold stress.ConclusionsHaplotype analysis revealed that most of the significant SNP loci are fixed in the winter or facultative types, while they are freely segregating within the un-adapted spring barley genepool. Although there is a major interest in detecting new variation to improve frost tolerance of available winter and facultative types, from a GWAS perspective, working within the un-adapted spring germplasm pool is an attractive alternative strategy which would minimize statistical issues, simplify the interpretation of the data and identify phenology independent genetic determinants of frost tolerance.

PHYSIOLOGICAL STUDY OF THE COMPONENTS OF WINTER-HARDINESS IN RHODODENDRON: COLD ACCLIMATION, DEACCLIMATION KINETICS, AND REACCLIMATION ABILITY

ISHS II International Symposium on Woody Ornamentals of the Temperate Zone PHYSIOLOGICAL STUDY OF THE COMPONENTS OF WINTER-HARDINESS IN RHODODENDRON: COLD ACCLIMATION, DEACCLIMATION KINETICS, AND REACCLIMATION ABILITY