High Drought Resistance Research Articles

Устойчивый к засухе сорт сои Волгоградка 1

The constant intensification of global soybean production is closely related to the breeding and seed production of this crop. Therefore, the research focused on the development of new varieties is quite relevant. The long-term screening at various agricultural backgrounds in dry and relatively favorable years helped identify a high drought resistance of soybean line 214, named Volgogradka 1, which is included in the State Register of varieties approved for use in the Lower Volga region (Russia) and Ural region (Kazakhstan). The variety is of medium-early 33 ripening, tall with a semi-determinant type of growth and a semi-compressed bush shape. It is characterized by high resistance to the main soybean diseases, such as Septoria blight, bacteriosis, mosaic compared to the standard varieties. It develops a high yield of biomass - from 3.29 to 10 t/ha in dry matter, which is higher than the standards (3.58-6.39 t/ha), so it is ideal for use on monofodder, it is a good predecessor that enriches the soil with nitrogen. Due to the high linear growth and, consequently, to the root system deeply developed in the soil, the semi-determinant type of development, the agrocenosis of the variety Volgogradka 1 can effectively use a small amount of precipitation during the growth season and at a low hydrothermal coefficient of the territory. The variety Volgogradka 1 is able to develop from 2.51 to 3.85 t/ha of grain in crops with irrigation due to its increased branching, tallness, resistance to lodging of the stem and a highly branched root system, which significantly exceeds the standard varieties in this indicator. The expansion of Volgogradka 1 sowings under irrigation conditions will increase the yield of soybean and to accelerate its import substitution.

Identification of cassava quality attributes preferred by Ugandan users along the food chain.

This study aimed to identify cassava quality attributes preferred by users along the food chain, in order to provide breeders with criteria for prioritisation. Survey and consumer-testing studies were conducted within Apac and Luwero districts in Uganda. Additionally, sensory evaluation by trained panellists was conducted to determine descriptors for assessing quality of boiled roots. Results revealed softness of boiled roots and in-ground storability as key attributes influencing varietal preference besides high yield, non-bitter roots, disease resistance, early maturity and drought resistance. For some attributes like in-ground storability, preference differed significantly between locations and showed differentiation by gender. Local varieties were found to be superior in quality attributes. From sensory evaluation, twenty-one descriptors associated with appearance, texture, taste and aroma of boiled roots were determined. Findings from this study are vital for breeders to adopt gender-responsive approaches in order to develop varieties that meet the needs and preferences of end users.

Water content of seedlings of Russian rice varieties

Increasing price of irrigation water reduces efficiency of rice production and increases interest in developing drought-tolerant varieties of rice. The varieties adapted to stress are characterized by: maintenance of water content, high dry matter content, reduced leaf area, stability of growth and synthetic processes, as well as a high content of pigments. It was found that the high water content of plant tissues under conditions of water stress indicates an increased ability of plant different species to adapt to changing water supply conditions and provide its higher drought resistance. According to the literature, the ratio of bound and free forms of water can also be an indicator of plant resistance to drought, since the bound form of water provides the cell’s water retention capacity. In this regard, the purpose of the work is to show the possibility of differentiating domestic specimens according to the characteristic in the initial phases of development, revealing the range of variation and sources for further breeding work to create varieties adapted to drought.

Parameters of adaptability, biological and economical valuable traits of soft wheat promising lines

Results of research of soft winter wheat new lines of hexaploid level by morphological features, biological properties and biochemical parameters were given. During 2018–2020 in the Northern part of the Central Forest-Steppe of Ukraine the assessment of the general adaptive capacity by the yielding capacity and biological-agronomic traits are given and promising ones are highlighted (Donzorna, Flonormyra, Polezoriana). The new wheat lines have proved themselves well given the consistently high winter, drought resistance, and productivity, coefficient of variation is low, variance of stability, homeostaticity, and selection value – high. According to the biochemical composition of the grain, the studied lines are characterized by medium and high ‘raw’ protein content and gluten content. New selection wheat lines own by the technological indicators (the volumetric bread outut of 100 g of drough, the total baking rating), flour ‘quite satisfactory’, ‘good’, and ‘excellent’ score (Sviatdonivka, Flonormyra). The new wheat line Donzorna is characterized by the presence of 1BL/1RS wheat-rye translocation, which distinguishes it as a donor of resistance to biotic and abiotic factors and requires further more detailed study.

Comparative assessment of plasticity, stability and homeostasis based on ‘1000 grain weight’ in winter rye cultivars developed at VIR

Background. In Russia, winter rye is a crop that provides food for people and feed for animals. Despite the obvious advantages of rye (high winter hardiness and drought resistance, plus the ability to grow in areas with poor soils and adverse climatic conditions), its area of cultivation has been reduced from 29 million hectares in 1913 to 872,000 ha in 2019. This situation can be improved by introducing rye cultivars with a stable yield of large grain under diverse growing conditions into commercial production.Materials and methods. The experimental part of the work was carried out in 2012–2017, in the experimental fields of Pushkin and Pavlovsk Laboratories of VIR. The target material was the accessions of low-pentosan winter rye cultivars developed at VIR. Data processing was performed using the analysis of variance according to B. A. Dospekhov. Adaptability and stability levels were calculated using the methods by S. A. Eberhart, W. A. Russell and L. A. Zhivotkov, those of plasticity and stability using the technique by G. C. Tai, the multiplicativity coefficient according to V. A. Dragavtsev, and the coefficient of homeostasis according to V. V. Hangildin, on the basis of ‘1000 grain weight’.Results and conclusion. The 1000 grain weight in the studied accessions varied from 30.0 to 48.2 g, with the average value of 40.8 g. The effect of the ‘test year’ factor on grain size was estimated at 65.5%, and of the ‘cultivar’ factor at 20.1%. The best conditions for large grain development were observed in 2013, 2015 and 2017 (45.7, 42.5 and 41.3 g, respectively). The most plastic, stable and homeostatic winter rye accessions were: Rushnik 2 (k-11820), ‘Krasnoyarskaya universalnaya’ (k-11818), ‘Bereginya’ (k-11822), Nika 3 (k-11823), and ‘Novaya Era’ (k-11814). The cultivars Rushnik 2, Nika 3, ‘Krasnoyarskaya universalnaya’, ‘Bereginya’ and ‘Novaya Era’ demonstrated high adaptability and can produce large grain under a wide range of varying environmental conditions.

Formation of Production Characters of Soya Genotypes [Glycine max (L.) Merr.] in the Areas of South-East Kazakhstan with Sufficient and Limited Water Supply

Moisture stress is a major environmental factor that limits the soy (Glycine max (L.) Merr.) yield worldwide. This study aimed to evaluate production characters of 98 varieties and collection samples of soy in the fields of the Almaty region of the Republic of Kazakhstan with and without irrigation. The experiment used a combination of features – weight of seeds from a plot, weight of 1,000 seeds, and seed plumpness – as the main markers for drought resistance assessment. Based on a comprehensive assessment of the working collection, soybean genotypes with high drought resistance were identified. These genotypes are useful genetic materials for soy breeding programs with the aim to increase yields and drought resistance. Varieties of the maturity group 00 can be cultivated in the Almaty region without irrigation, since these accessions avoid moisture stress by shortening the vegetation period. These samples can also be recommended for cultivation in non-irrigared areas of Eastern and Northern Kazakhstan. The highest productivity potential in the Almaty region was found in varieties of the maturity group II. However, their cultivation without irrigation will lead to a maximum decrease in yield.

Adaptive abilities of corn hybrids under different irrigation modes and moisture supply in the arid Steppe of Ukraine

Aim. The study presents the results of the research on the productivity features and adaptability parameters of domestic corn hybrids under different irrigation modes and water supply under conditions of the Arid Steppe. Methods. The general scientific, special selection genetic, computational and comparative research methods were used. The research object was modern corn hybrids of domestic selection of different maturity groups. The hybrids were sown under different irrigation modes (common sprinkling, drip irrigation, sub-irrigation). Results. The retrospective analysis of the productivity of main grain crops in the area of the Arid Steppe over a 130-year period showed that the highest rates of an increase in productivity were recorded in corn. An annual increase in its productivity was 31 kg/ha per year and it was due to the use of new varieties (hybrids) and the improvement of growing techniques. Irrigation made it possible to realize potential productivity of new hybrids and increase the productivity from 6.59 to 82.3 c/ha. Productivity rose 12.5 times over a 130-year period, the annual increase being 58 kg/ha per year. Without irrigation the grain productivity was the highest in early-maturing hybrids – 3.28 and 3.05 t/ha indicating their high drought resistance. The use of these hybrids is appropriate under conditions of water-saving irrigation modes on irrigated lands with a low hydro-module and on dry massifs. A fall in the productivity under other irrigation modes was from 0.41 to 1.93 t/ha. Conclusions. Under irrigation conditions it is necessary to use corn hybrids with a genetically programmed reaction to optimal growing conditions (an optimal mode of soil moisture and mineral nutrition).
 Keywords: hybrid, corn, irrigation, adaptability, drought resistance, grain, selection.

Biological Flora of the British Isles:Quercus rubra

AbstractThis account presents information on all aspects of the biology ofQuercus rubraL. (Red Oak, Northern Red Oak; syn.Q. borealis,Q. maxima) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of theBiological Flora of the British Isles:distribution; habitat; communities; responses to biotic factors; responses to environment; structure and physiology; phenology; floral and seed characters; herbivores and disease; history; and conservation.Quercus rubrais a large deciduous tree native to eastern North America. In its native range this species is one of the most important mid‐successional tree species. Since the 18th centuryQ. rubrahas been introduced into forest management in Europe and elsewhere. Currently,Q. rubrais a naturalized species in 23 countries. It is an important source of wood, and this was one of the most important reasons for its introduction in forests. In forest management this species is valued for its high growth rate and drought resistance. Red Oak is also widely cultivated in Europe for its ornamental value—red leaves in autumn and smooth, grey bark.Red Oak is a threat to native species within its introduced range as it can alter environmental conditions beneath its canopy, especially by decreasing light availability and litter decomposition rate. Such conditions also contribute to biotic homogenization of the understorey vegetation.Q. rubrais widely dispersed by small mammals and birds, up to 1,500 m from seed sources, thereby increasing its potential invasiveness.In EuropeQ. rubraseems to be less prone to herbivores and fungi, in contrast to its native range, where it is grazed by ungulates and insects, and infected byPhytophthoraand oak wilt. Due to its higher tolerance to drought than native European oaks,Q. rubrais claimed to be one of the species replacing native trees which are decreasing due to climate warming. However, consideration of all possible consequences is needed in wide‐scale introduction of alien species, such asQ. rubra, due to negative impacts on native ecosystems.

Screening of diverse cassava genotypes based on nitrogen uptake efficiency and yield

As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is usually cultivated on hilly areas that are nutrient-poor. Nitrogen (N) is one of the significant factors affecting cassava yield. A double factorial (N level×genotypes) split-plot field experiment was conducted to analyze differences in yield and N accumulation of 25 cassava genotypes under low-N conditions to screen for cassava genotypes with high-N efficiency. The two-year field experiment showed that cassava yield and N accumulation are determined by specific genotypes, soil N levels, and year. Among these factors, soil N levels are the main factors that are responsible for differences in cassava yield. When yield and relative N accumulation under low-N conditions were used as screening markers, we identified an efficient and responsive genotype (SC10), and two inefficient and non-responsive genotypes (SC205 and GR5). The efficient and responsive genotype and the inefficient and non-responsive genotype can be used as study materials to further reveal the mechanisms for high-N efficiency in cassava.

Оцінка посухостійкості сортів і гібридних форм обліпихи крушиноподібної (Hippophae rhamnoides L.) в умовах Лісостепу України

The authors present the results of studying the leaves water regime of the sea buckthorn 5 cultivars and 16 hybrid forms in the Ukraine’s Lisosteppe. In the recent years the climatic conditions of this region are characterized with the increased average annual temperature, the vegetation period with unstable humidity, the periods without precipitations often occur. High air temperature and its low humidity cause air and soil drought. Such temperature fluctuations and insufficient precipitations amount affect adversely the plant growth and development. This increases the risk of the ovary shedding, decreases the crop quantity and quality, influences negatively the generative buds establishment as well as the future crop. In our researches the laboratory and field methods were applied in order to determine drought-resistant cultivars and hybrids. The leaves water content was analyzed as well as their water-holding capacity by means of calculating the water loss per time unit when withering artificially, exposing the leaves in the conditions of drought. Taking into account the changes of the leaves water-physical parameters, new perspective sea buckthorn forms were selected with very high drought resistance – 1-15-2, 1-15-5 and 1-15-11, while 1-15-6, 1-15-1, 1-15-3, 1-15-4, 1-15-9, 1-15-10, 1-15-13, 1-15-14, 1-15-15, Chuiskaia , Nivieliena and Hergo were referred to the groups of high and average resistant, and 1-15-12, 1-15-16, Moskovskaia Krasavitsa, 1-15-8, 1-15-7 and Moskvichka to low resistant. New promising forms of sea buckthorn 1-15-2, 1-15-5, 1-15-11 were identified previously as donors of drought-resistance.

Influence of abiotic factors on CO2-gas exchange of Pinus pallasiana, Juniperus excelsa and Arbutus andrachne

The complex interactions among environmental factors as incident light, temperature and soil water content create the need for used physiology-based models which describe plants performance under current and changing climatic conditions. In the present work the net photosynthetic rate of Pinus pallasiana D. Don, Juniperus excelsa M.Bieb. and Arbutus andrachne L. was modeled as a function of light irradiance using the modified rectangular hyperbola model, which is capable of describing the photoinhibition by the non-rectangular hyperbola function. A comparative assessment of the adaptive response of the photosynthetic apparatus plants on the effect of abiotic factors and their strategies in maintaining an optimal water balance in accordance with environmental conditions has been performed. The parameters of light curves of photosynthesis under conditions of full sunlight, moderate shading and drought are determined. In relation to light, Pinus pallasiana is characterized by wider ecological amplitude compared to Juniperus excelsa and Arbutus andrachne. Inefficient use of low-intensity of photosynthetically active radiation by immature plants Pinus pallasiana and Juniperus excelsa indicates poor shade tolerance and inability to resume in shade-type forests. Due to the low plasticity to changes in the light regime, Arbutus andrachne L. may experience a significant lack of light in strong shading. Arbutus andrachne has the highest ability to actively rearrange water regime in accordance with its external moisture supply, which causes the highest drought resistance, and Juniperus excelsa has a slightly lower capacity. Tolerance to hydrothermal stress in Pinus pallasiana is significantly lower than in Arbutus andrachne and Juniperus excelsa.

Morphological variability, biochemical parameters of Hippophae rhamnoides L. berries and implications for their targeted use in the food-processing industry

The results of studying the morphological and biochemical parameters of plants of sea buckthorn are presented. For the first time, genotypes of sea buckthorn ranked by ontogenetic and morphological characteristics and ecological features (relation to the level of soil moisture and humidity air, providing soil nutrients, its рН, amount and mode of precipitation, lighting, positive and negative temperatures) natural, semi-natural and anthropic coenopopulations genotypes of sea buckthorn be ranked by ecomorphic affiliation to certain climate ecotypes (рolissia, forest-steppe) and subecotypes (western-forest-steppe, northern-forest-steppe, рolissia–forest-steppe, central-forest-steppe). Biotypes, that have been a limited ability to carry soil and atmospheric drought (in which the root system is well developed, ground part with copious leaf cover), selected in natural and semi-natural places of growth appertain tо mesophytes (Ms). The genotypes, selected in catchment areas, the lowlands of Forest-Steppe, Polissia of Ukraine, appertain to mesohygrophytes (MsHg) (by morphological and physiological features characterized by weak drought and heat resistance – 6 points, require sufficient moisture and sufficient provision of organic and mineral substances, are weak frost resistant, but very resistant to temperature changes during the winter). A special group makes up widely ecological flexibility mesophyte plants of sea buckthorn – mesoxerophytes (wfMsKs) – are presented рolissia–forest-steppe subecotype, characterized by wide environmental plasticity, due to the high winter, drought and frost resistance, compared to others subecotype. Its have adapted to withstand prolonged of soil and air in the extreme phases of ontogeny, in particular, in the phase of fruit filling and ripening, giving high stable harvest. Particular breeding and economic value in terms of formation stably high yields under conditions of global climate change, its aridization and displacement borders zoning of fruit crops have xeromesophytes (KsMs) presented central forest-steppe subecotype – in view of the its relatively average demanding to soil and air moisture and resistance to moisture deficiency. Highlighted forms – sources of valuable economic features of sea buckthorn (large berry, firm skin, long berry peduncles and dry separation of berries and іts increased biological value, freezing capacity and making beverages, high yields.

Biochemical and molecular-genetic markers of adaptability and quality of genotypes in cultural and wild cereal plants

We proved that plants A. cylindrica, T. spelta, T. turgidum, T. sphaerococcum, T. vavilovii, T. persicum, T. araraticum, T. aestivum var. barbarossa, and T. aestivum var. ferrugineum, owning high drought resistance, have a stable high productive potential and quality indicators of grain (protein, gluten, dietary fiber content), that allows use them in the production of products functional purpose (bakery, confectionery, sour-dairy products, including yoghurts, and dessert cheese). Implementation mechanisms are disclosed adaptive potential plants of cultural and wild cereals by biochemical (protein content, gluten, starch in seeds, the presence of gliadin proteins (Glі-1В1, Glі-6D2, Glі-6D3, Glі-6В2), molecular-genetic markers (allele genes of drought resistance – Dreb А1, Dreb В1, Dreb D1; glutenins Glu-D1) and morphological-ontogenetic criteria. For the first time for successful address introduction cultural and wild cereal plants suggested by the criteria of mechanisms drought resistance to rank plants by potential ecological valence regarding the unfavorable hydrothermal regime. Differentiation of genotypes based on elements of plant strategies: features of their ontogeny, morphological characteristics, physiological and biochemical parameters, biochemical and molecular-genetic markers. In this connection, genotypes of cultural and wild cereal plants in conditions in sіtu by sensitivity on the effect of hydrothermal stress are divided into xerophytic, mesophytic and intermediate – xerophytic-mesophytic types of development. That's it ranking underlying on the principles of autecological approach, manifestation of a multi-level system of answers plant organisms at different levels of integration, as adaptive reactions. In particular, mechanisms such as: functional stability (stipulated structural and functional features of plants), morphological tolerance (the ability of plants to resist damage without reducing performance), ontogenetic evasion (stability due to features ontogenetic development), ecological plasticity of the organism and plant populations as a whole. The obtained results of the biochemical and molecular genetic markers of adaptability and quality indicators of genotypes cultural (wheat, triticale, rye) and wild cereals (A. cylindrica, T. spelta, T. turgidum and others) are important in breeding and successive targeted use in the food industry are given.

First Report of Dwarf Disease in Foxtail Millet (Setaria italica) Caused by Barley Yellow Striate Mosaic Virus in China

Foxtail millet (Setaria italica) is an important cereal crop with high drought resistance and widely cultivated in northern China. Virus disease in foxtail millet is a serious problem because of yield decrease and difficulty in control. In Korea, rice black-streaked dwarf virus, rice stripe virus, and barley virus G have been detected on foxtail millet, whereas in China only barley yellow dwarf virus has been reported on foxtail millet (Oh et al. 2017; Pei et al. 1984). In the summer of 2018, a foxtail millet variety, Yugu18, showed virus-like symptoms of dwarfing, shortening of internode, stunting, and head sterility in Shijiazhuang of Hebei province, with an incidence of about 15%. To identify the viral diseases on foxtail millet, 10 samples showing the above virus-like symptoms were collected and stored at –80°C for RNA extraction. Total RNA of the samples was extracted by TRIzol Reagent (Invitrogen, Carlsbad, CA), and then the 10 RNA samples were combined into one sample for further detection and next-generation sequencing (NGS) was performed with an Illumina HiSeq 2000 sequencer. The whole NGS procedure was implemented by Majorbio Bio-Pharm Technology Company (Shanghai, China). In the pooled sample, 56 viral contigs matching barley yellow striate mosaic virus (BYSMV) were obtained in the range of 30 to 1,259 bp, and the NGS results were confirmed by the following reverse transcription PCR (RT-PCR) assay. First, a BYSMV-specific primer set (5′-TTTGATGATGATGTCCCTG-3′ and 5′- GATGTATTCTTCTCTTCTCC-3′) was designed according to the determined phosphoprotein (P) gene sequence of BYSMV in wheat (GenBank accession no. KP163566), and each of the above 10 RNA samples was analyzed by RT-PCR assay. In the RT-PCR assay, seven out of 10 samples produced a single amplicon of the expected size (∼600 bp), and three randomly selected positive products were sequenced. Nucleotide BLAST search indicated that the three sequences showed 99% identity with the BYSMV P gene from a wheat isolate. The sequences of the BYSMV P gene in foxtail millet were submitted to GenBank with the accession number MN434075, MN434076, and MN434077. BYSMV belongs to genus Cytorhabdovirus, which was first reported in Italy and was recently found on wheat and rice in China (Appiano et al. 1974; Wang et al. 2015). In this study, BYSMV was detected in samples of foxtail millet with virus-like symptoms through RNA sequencing using NGS and confirmed by RT-PCR. To our knowledge, this is the first report of BYSMV on foxtail millet in China. According to our observation, the yield of foxtail millet decreased by almost 10% with a great quantity of head sterility in Shijiazhuang because of virus infection, and this disease may become a serious threat to foxtail millet production in other regions of China. Further studies will be carried out to identify the pathological properties, host range, and resistance germplasm resources in foxtail millet. Therefore, the identification of BYSMV on foxtail millet has great significance in providing an appropriate strategy for monitoring, prevention, and control of dwarf disease in China.

Transcriptome profiling using RNA-seq to provide insights into foxtail millet seedling tolerance to short-term water deficit stress induced by PEG-6000

Foxtail millet (Setaria italica L.) with high drought resistance, is grown widely in arid and semi-arid regions of the world, and it is a new model plant for genetic and molecular studies. To uncover the molecular mechanisms of stress-tolerance in different genotypes of foxtail millet, physiological analyses combined with transcriptional profiling were conducted using a time-course analysis on two foxtail millet genotypes Damaomao (DM) and Hongnian (HN). The genotype DM performed better than HN under water deficiency, with more moderate relative water content (RWC) and chlorophyll decline. Further physiological and RNA-seq investigations revealed that the two genotypes possessed high conservatism in some vital biological pathways which respond to drought stress, involving hormone synthesis, proline, and soluble sugar synthesis, and reactive oxygen species (ROS) metabolism. However, some genes related to these pathways showed different expression profiles. Likewise, the lower malondialdehyde (MDA) content in HN than DM may be explained by the observation that HN contained more activated genes in the ascorbate-glutathione cycle using KEGG pathway analysis. Overall, abscisic acid (ABA) response genes, ROS scavengers which were probably involved in signaling responses, a set of enzymes involved in proline and soluble sugar synthesis, channel protein genes, and transcription factors, encompassed the early strategy of foxtail millet response to drought. These findings provide a comprehensive molecular view of how different foxtail millet genotypes respond to short-term osmotic stress.

БИОЛОГИЧЕСКИЕ И ХОЗЯЙСТВЕННЫЕ ОСОБЕННОСТИ ИНТРОДУЦИРОВАННЫХ В КРЫМ СОРТОВ ЧЕРЕШНИ

As a result of a long-term comprehensive study of the Nikita Botanical garden cherry gene pool, an trait collection was formed. Among the introducents it included 54 varieties as sources and donors of valuable traits. Of these, sources of high winter hardiness identified ten varieties, high drought resistance — seven, resistance to cracking of fruits — five, high resistance to moniliosis — one, for coccomycosis — five, late flowering period — five, large fruit — eight, early ripening — eight, high taste — ten, high density flesh — nine, high stable yield — eighteen. The acceleration and intensification of the breeding process depends on the correct selection of parent pairs.

Water use Efficient Sunflower Hybrids having Diverse Cytoplasmic Background

Abstract A set of fifty two hybrids developed through line×tester breeding design were sown in randomized block design with three replications to evaluate their performance for seed yield under two environments (normal irrigation and water stress). Drought resistant indices and multivariate statistical analysis from the pooled data obtained from water stress and normal irrigated environments over the two years. Hybrid PRUN-29A × RCR-8297 (1.55) and 40A × P100R (1.55) had the largest stress tolerance index (STI) rate and hybrid ARG-2A × P69R the smallest rate (a high STI rate for the genotype represents its high drought resistance and its high yielding potential). Hybrid ARG-6A × P69R (2.41) had the largest extent (susceptible) of Stress susceptibility index (SSI), while hybrid E002-91 × RCR-8297 (0.13) had the least (resistant) extent a large extent of this index indicates the genotype susceptibility to drought. In terms of yield stability index (YSI), hybrid 40A × RCR-8297 (0.51) and ARG-6A × P69R (0.51) and hybrid ARG-2A × P69R (1.18) had the smallest and the largest rate respectively (genotypes with high YSI are expected to yield highly in stress conditions. Hybrid 40A × RCR-8297 (30.36) and PRUN-29A × P69R (−10.07) displayed the least and the most amount of tolerance index (TOL) index, a high amount of TOL is a sign of genotype susceptibility to stress. Hybrid PRUN-29A × P69R (1.53) displayed the least extent of yield index (YI), while hybrid ARG-6A × P69R (0.51) and 40A × RCR-8297 (0.51) displayed the highest extent.

Drought mediated physiological and molecular changes in muskmelon (Cucumis melo L.).

Water deficiency up to a certain level and duration leads to a stress condition called drought. It is a multi-dimensional stress causing alteration in the physiological, morphological, biochemical, and molecular traits in plants resulting in improper plant growth and development. Drought is one of the major abiotic stresses responsible for loss of crops including muskmelon (Cucumis melo. L). Muskmelon genotype SC-15, which exhibits high drought resistance as reported in our earlier reports, was exposed to deficient water condition and studied for alteration in physiological, molecular and proteomic profile changes in the leaves. Drought stress results in reduced net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration (E) rate. With expanded severity of drought, declination recorded in content of total chlorophyll and carotenoid while enhancement observed in phenol content indicating generation of oxidative stress. In contrary, activities of catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), and guaiacol (POD) were increased under drought stress. Peptide mass fingerprinting (PMF) showed that drought increased the relative abundance of 38 spots while decreases10 spots of protein. The identified proteins belong to protein synthesis, photosynthesis, nucleotide biosynthesis, stress response, transcription regulation, metabolism, energy and DNA binding. A drought-induced MADS-box transcription factor was identified. The present findings indicate that under drought muskmelon elevates the abundance of defense proteins and suppresses catabolic proteins. The data obtained exhibits possible mechanisms adopted by muskmelon to counter the impacts of drought induced stress.

Responses of soil labile organic carbon fractions and stocks to different vegetation restoration strategies in degraded karst ecosystems of southwest China

The effective restoration of degraded areas, resulting in the sequestration of significant amounts of soil organic carbon (SOC) and labile soil organic carbon fractions (LOCF), is essential for mitigating global climatic changes. It is therefore important to improve our understanding of the responses and magnitudes of SOC and LOCF during restoration processes in degraded land like karst ecosystems. In this study, we selected four different restoration strategies: (1) not subjected to any management practices, mainly bare land (BL); (2) Pinus yunnanensis plantation (PY), native and characterized by slow growth and high drought resistance; (3) Eucalyptus maideni plantation (EM), non-native and characterized by rapid growth and high adaptability; (4) natural regeneration of secondary forest (SF). The SOC concentrations, SOC stocks, sensitive indicators of LOCF (microbial biomass C (MBC), permanganate oxidizable C (KMnO4-C), dissolved organic C (DOC), water soluble organic C (WSOC)), non-labile C (NLC), and the carbon pool management index (CPMI) were investigated. The different reforestation strategies had significant effects (p < 0.05) on SOC stocks; compared with BL, the SOC stocks of SF, EM, and PY increased by 57.7, 38.0, and 26.9%, respectively. Both the LOCF and the NLC stocks were significantly increased by the different restoration strategies relative to the BL, while natural vegetation restoration was more beneficial for C sequestration than afforestation. Compared with BL, in SF, EM, and PY, the CPMI increased by 70.1, 35.8, and 32.6%, respectively. These findings suggest that although afforestation can significantly increase C sequestration, natural regeneration may be a more effective approach in terms of SOC sequestration. Soil C accumulation would be limited by nitrogen and phosphorus during the vegetation restoration in the karst areas. In degraded karst ecosystems, the CPMI could be used as a representative index in evaluating the impacts of vegetation restoration on SOC concentration and soil quality.

Norway Spruce (Picea abies L.) Provenances Use Different Physiological Strategies to Cope with Water Deficit

Research Highlights: In this study, we found different regulatory mechanisms in two contrasting provenances of Norway spruce responding to progressive drought stress. Background and Objectives: In the context of climate and environmental changes, the following question of high importance in scientific studies is: How will Norway spruce, which forms a dominant component in European mountain and boreal forests, be able to cope with the increasing frequencies and intensities of drought periods? The aim of the study was to investigate the physiological responses of eight-month-old seedlings, as a most vulnerable phase of forest tree life, for different spruce provenances, to find out variable strategies in relation to controlled drought stress. Materials and Methods: We performed an experiment under controlled conditions with spruce seedlings from a climatologically warmer stand of 410 m above sea level (a.s.l.), and a moderately cool stand of 931 m a.s.l. The soil water content, leaf predawn water potential, the osmotic potential of needles, the relative water content of needles, and the photosynthetic performance and the contents of primary metabolites (proline and abscisic acid) were investigated as indicators of the spruce seedlings’ responses to water stress. The status of the indicators was analyzed at different temporal intervals, using repeated measures analysis of variance (ANOVA), reflecting the seedlings’ water conditions (early drought, drought, or recovery). On a daily basis, the differences among the indicators were tested with one-way ANOVA. A principal component analysis (PCA) was used to identify the provenance-specific responses of tree drought indicators in a multi-dimensional data set. Results: The responses to drought stress differed between the provenances. Whereas seedlings of ‘warm’ provenance from a low altitude performed a conservation strategy, with high amounts of accumulated abscisic acid and closing the stomata faster, the reactions of ‘cool’ provenance seedlings from a higher altitude were not so sensitive and the plants’ water supply and photosynthetic performance remained significantly higher. These findings indicate that a higher drought resistance in ‘cool’ provenance could be related to greater amounts of proline amino-acids, which are accumulated from the beginning of the drought simulation. Furthermore, proline accumulation resulting in increased stress tolerance is controlled through another mechanism than osmotic adjustment. Conclusions: The observed variations in the regulatory mechanisms used to develop adaptive strategies in different provenances are an important factor for seedling survival under a changing climate.