Adverse Growing Conditions Research Articles

Water‐saving techniques for restoring desertified lands: Some lessons from the field

AbstractNature‐based solutions can significantly contribute to restoration projects in areas affected by desertification processes, where they are necessary for reversing land degradation. Currently, one innovative solution is The Cocoon™, which has been designed as a new ecotechnology for improving seedling establishment. The Cocoon consists of a doughnut‐shaped container made of recycled cardboard that provides water and shelter at least during the first year of a seedling, which is the most critical for plant establishment. To determine the effectiveness of this ecotechnology under different conditions, the Cocoon was tested on a variety of soils, climates, vegetation, and land uses. Six planting trials were performed in Spain and Greece, which covered a range from humid to arid climates. With the objective of studying its functionality, the survival of the seedlings, their vigor, and growth were monitored for 2 years. Compared with conventional planting systems, the Cocoon has effectively increased seedling survival, especially under dry growing conditions (low rainfall, soils with low water holding capacity). The Cocoon also allowed for higher growth of some species (olive trees, holm oaks, and Aleppo pines). Moreover, a positive correlation between the rainfall on the site and the biodegradation degree of the Cocoon device was observed. Overall, the Cocoon becomes more efficient in arid climates or adverse growing conditions.

Biological Features Of The Distribution Of Root Systems Of Perennial Legume Grasses In The Context Of Climate Change

The key factor in the choice of perennial legume grasses in the face of climate change is their drought resistance, because the development of roots directly affects this property, as well as determines their fertility. The purpose of the study was to establish what morphological and biological characteristics of grass roots ensure economic characteristics in the context of climate change. Methods of observation, comparison, and field experiment were used. The study found that the roots of alfalfa have the greatest depth in the soil, spread in the horizontal direction, the thickness of the root neck and lateral roots, which ensures plasticity, durability, and productivity of its crops. The roots of white melilot have the greatest depth in the soil, the thickness of the root neck, central root and lateral roots, their spread in the horizontal direction, which affects the drought and frost resistance of crops. The roots of birdsfoot trefoil are distinguished by the greatest number of renewal buds on the root neck, the smallest depth, and the thickness of the root neck, which affects productive longevity and the possibility of growth in poor and acidic soils. The roots of eastern galega have the greatest depth of the main plant, distribution in the horizontal direction, the thickness of the central root, which affects productive longevity and high biological plasticity. The roots of Hungarian sainfoin are distinguished by the greatest distribution in the horizontal direction and the deepest placement of the main branching, which affects high biological resistance to adverse growing conditions. It was also found out that the roots of meadow clover have the smallest spread radius in the horizontal plane, the thickness of the central and lateral roots, which determines the possibility of its cultivation in the field crop rotation. These findings would facilitate the selection of perennial legume grasses to achieve their full potential in the face of climate change

Агроекологічна стійкість сортів квасолі звичайної до несприятливих умов вегетації

Агроекологічна стійкість сортів квасолі звичайної до несприятливих умов вегетації

THE EFFICIENCY OF ORGANIC BIOSTIMULANTS FOR KOHLRABI SEEDS AND PLANTS TREATMENT

The research reveals a versatile positive effect of organic bio stimulants Regoplant, Stimpo, and Emochka on kohlrabi cabbage plants. Soaking the seeds for 12 hours and foliar dressing of plants during vegetation with solutions of growth regulators contributed not only to increase the total yield of stems but also to enhancing growth indices of kohlrabi plants and at the same time ensuring better resistance to adverse growing conditions. The highest yield was obtained for the soaking seeds for 12 hours and 2 foliar dressings. Thus, in kohlrabi varieties ‘Delikatesna Bila’ and ‘Violeta’, the highest yield of stems (23.9?25.2 t/ha) was obtained under the influence of growth regulators Regoplant and Stimpo. In the experiment, a high yield of commodity stems was obtained in variety ‘Delikatesna Bila’ (86?93%) and in variety ‘Violeta’ (86?91%), which was on average higher by 8.0 and 5.6% than in the control treatment. The use of biostimulants ensured the yield of soluble dry matter higher by 0.2%, 0.4%, 0.8%in‘Delikatesna Bila’ and by 0.8%, 1.0%, 0.3% in ‘Violeta’, respectively, compared to the control treatment

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ ОТЕЧЕСТВЕННЫХ ПОДВОЕВ ТЫКВЫ ДЛЯ ПРИВИВКИ ОГУРЦА В ЗАЩИЩЕННОМ ГРУНТЕ

When growing herbaceous vegetable crops in the world practice, great importance is given to the use of grafting method. The development of environmentally safe methods to increase the yield and resistance of plants to adverse growing conditions is very relevant in vegetable production. One such method in pumpkin crops is grafting. The aim of our work was to study the effect of domestic pumpkin rootstock on growth, development and yield characteristics of cucumber hybrid using grafting method. Grafting on pumpkin species improved the growth and development of plants depending on the rootstock, compared with rootstock plants. The aim of our research was to study the influence of domestic pumpkin rootstock on the growth, development and yield characteristics of the cucumber hybrid (scion). As a scion, the variety (Asylum), recommended for cultivation in protected ground conditions, was used, which was grafted on five domestic rootstocks: 1 (Mozoleevskaya 10), 2 (Karina), 3 (Aphrodite), 4 (Mindalnaya) and Russian selection 5 (Stofuntovaya) pumpkins from vegetable and melon crops. According to the generally accepted method, the graft was grafted (cucumber Asylum) on the rootstocks of pumpkin. Using a sample of pumpkin 1 (Mozoleevskaya 10), flowering began on the fifth day earlier in comparison with non-grafted plants, and when grafting on a sample of pumpkin 4 (Aphrodite), the fruit ripened earlier by six days. To get the greatest increase in early productivity by 30%, it is possible to use both rootstocks. A significant increase in total yield was provided by samples of rootstocks 2 (Karina) – 3.9 kg/m2 and 3 (Stofuntovaya) - 8.0 kg/m2. The grafted cucumber plants with all the rootstocks used were superior to the root ones in height, in terms of the percentage of marketability of fruits and in terms of fruit weight. At the beginning of fruiting on grafted cucumber plants, the number of female flowers increased depending on the sample. In all grafted plants, the dry matter content in the fruit increased significantly. Because of our research, rootstocks 2 (Karina) and 3 (Stofuntovaya) were noted, which are recommended for use in further research breeding work and the production of grafted plants.

Seasonal Nutrient Cycling and Enrichment of Nutrient-Related Soil Microbes Aid in the Adaptation of Ramie (Boehmeria nivea L.) to Nutrient-Deficient Conditions.

The breeding for varieties tolerant of adverse growing conditions is critical for sustainable agriculture, especially for ramie (Boehmeria nivea L.). However, a lack of information on the tolerance of ramie to nutrient-deficient conditions has hindered efforts to breed ramie varieties tolerant of such conditions. The main objective of this study was to explore the tolerance strategies of ramie plants under poor soil conditions using long-term (8–9 years) field trials. Genotypes of Duobeiti 1 and Xiangzhu XB were highly tolerant of poor soil conditions. The contributions of seasonal nutrient cycling and rhizobacteria to the ability of ramie to tolerate poor soil were tested. Nitrogen and phosphorus retranslocation to the root at the end of the growing season helped ramie adapt to poor soil conditions. The contribution of the microbial community was analyzed using high-throughput Illumina MiSeq sequencing technology. The enrichment of beneficial bacteria (mainly Bradyrhizobium, Gaiella, and norank_o_Gaiellales) and the reduction of harmful fungi (mainly Cladosporium and Aspergillus) also contributed to the ability of ramie to tolerate poor soils. The results of this study provide new insight into the ability of ramie to tolerate adverse conditions and aid future efforts to breed and cultivate ramie tolerant of adverse conditions.

COMPARATIVE EVALUATION OF BEAN VARIETIES OF COMMON ADAPTABILITY

The varieties of beans that are the least responsive to growing conditions (primarily in terms of moisture supply) by changing the weight of 1000 grains are selected. Coefficient of plasticity (bi <1): UD0302683, UD0302746, UD0302642, UD0303533, UD0302256. These cultivars slightly reduced the weight of 1000 grains due to the deterioration of the moisture supply, ie they are drought-resistant. It should be noted that the varieties that were characterized by the maximum value of grain productivity in quantitative terms, also showed maximum variability in grain productivity over the years of research. These are primarily varieties: UD0300565, the weight of grain from the plant which was 10.6 g, as well as UD0302642, the weight of grain from the plant was 10.5 g, UD0302746 - 11.4 g. - 20%, and UD0302746 - 17%. Therefore, the production needs varieties of common beans that will provide stable and above average yields under adverse growing conditions, and at optimal high levels. Therefore, varieties of common beans were distinguished, which were characterized by lower absolute values in grain productivity and higher stability of the trait during the study period. Such cultivars included UD0303533, whose grain productivity was 8.53 g, and the regression coefficient (bi = 0.81), coefficient of variation (V = 18%), coefficient of agronomic stability (As = 82%); UD0301899 - 7. 88 g, regression coefficient (bi = 0.65), coefficient of variation (V = 15%), coefficient of agronomic stability (As = 85%). That is, these varieties did not respond much to the deterioration or improvement of growing conditions while maintaining stable grain productivity. Given that the coefficient (As) exceeds 70%, the selected varieties of common beans were stable.

VARIABILITY OF BEAN VARIETIES SAMPLE BY YIELD STRUCTURE STRUCTURE AND ADAPTABILITY

The study of quantitative characteristics controlled by polymer genes is rather complicated due to their significant variability, depends on the environment conditions, and the general picture of their inheritance and variability is masked by the modifying action of heterosis in the first generation. New varieties should have a balanced development of all elements of productivity, resistance to abiotic and biotic factors, and not just the maximum value of the individual characteristic. Plant growing conditions are important in forming their resistance to various diseases. In nature, pathogens and plants are affected by the weather conditions that are constantly changing. The research objective was to determine the variability level and to identify the patterns of inheritance of valuable commercial-biological traits for the selection of productive and adaptive forms of common bean (Phaseolus vulgaris L.). The research was conducted during 2014–2016 in the conditions of the research plot of the Department of Plant Production, Selection and Bioenergetic Cultures of Vinnytsia National Agrarian University. The region of the research by its natural conditions refers to the central subzone of the Right Bank Forest-Steppe. The hydrothermal conditions of the 2014 and 2016 surveys were typical of the average yearly indices of the research area and the year 2015 was characterized by a significant deficiency of precipitation and high temperature air conditions. The research material were the varieties of common bean provided by the National Center for Plant Genetic Resources of Ukraine and hybrid combinations obtained as a result of intervarietal crossings. Sowing was carried out by the temperature regime of soil 10–12 °С at the depth of seeding and stable increase of average daily air temperature. The placement of the plots was consistent, the varieties were sown in a six-time repetition. The wide-row sowing with a width of rows of 45 cm was used. The total area of the plots was 1.35 m², and the account one is 1.0 m². Sowing was carried out with the seeding rate of 18 similar seeds per 1 linear meter, the standard was placed in 10 numbers. The general adaptability of the common bean varieties for the research years was determined by regression coefficient (bi) and the stability variance (Sі2). Assessment of the morphological features variation was carried out by the variationcoefficient (V, %). The ecological variation coefficient (Vе, %) was determined by the ratio of the average sign to its standard deviation. The determination of ultrastability (Nom) and agronomic stability coefficient (As) was made. Conclusions. As a result of the three year research, it was established that the highest resistance to bacteriosis had such varieties as UD0303601, UD0303526, UD0303543 and UD0303557. The varieties UD0303601, UD0303526 were resistant under adverse growing conditions; the highest resistance to bacterial wilding, including under adverse growing conditions, was provided by the varieties UD0300414, UD0301063 and UD0303543; according to the resistance to variegation the following varieties were selected: UD0303543, UD0303557, and UD0303610 (they were better under all growing conditions). Key words: bean varieties, elements of crop structure coefficient of variation, variability.

Features of formation of productivity of sugar beets hybrids of domestic breeding

Purpose. To reveal features of formation of productivity of modern sugar beet hybrids of domestic selection.Methods. Field, laboratory.Results. Studies show that the lowest yields of sugar beets were obtained in 2016, 2017 and 2019. Moreover, the conditions of the unstable humidification zone of the Right-Bank part of the Forest-Steppe of Ukraine were mainly characterized by unstable precipitation, a decrease in their amount, as well as increased average daily air temperatures. Therefore, the selection of high-yielding hybrids of sugar beets to obtain a high level of productivity is relevant. As evidenced by the data comparing the yield of sugar beet root crops on the test site, they significantly exceeded the average indicators for Kiev region by 10.7–20.0 t/ha, and only in arid 2016 the difference was minimal – 4.6 t/ha. The high stability of the trait “sugar content in root crops” is inherent not only in hybrids with low parameters of its manifestation, but is largely determined by the genetic characteristics of the hybrid. Three clusters were identified based on the reaction of hybrids to growing conditions. The first cluster included triploid hybrids: ‘Zluka’, ‘Oleksandriia, ‘Olzhych’, ‘Kvarta’ and ‘Konstanta’, the second one – the triploid hybrid ‘BTs ChS 57’ and diploid ‘Vesto’, the third cluster - the triploid hybrid ‘Sofiia’ and diploid ‘Ukrainskyi ChS 72’.Conclusions. Proper selection of high-yielding hybrids resistant to adverse growing conditions in the zone of unstable moisture of the Forest-Steppe of Ukraine is extremely important, because the biological characteristics of hybrids affect 45% of the amount of sugar harvest, but the growing season by 33% and the interaction of factors was 17%. It was found that despite the difficult weather conditions, the highest yields were formed by hybrids: ‘Anichka’ – 70.1 t/ha, ‘Ramzes’ – 70.5 t/ha, ‘Romul’ – 73.0 t/ha and ‘BTs ChS 57’ – 73.4 t/ha. But the maximum sugar content in root crops was in hybrids: ‘Ukrainskyi ChS 72’ – 17.3%, ‘Zluka’ – 17.3% and ‘Sofiia’ – 17.7%. Accordingly, the maximum sugar harvest was provided by hybrids: ‘BTs ChS 57’ – 12.1 t/ha and ‘Romul’ – 12.2 t/ha.

Ocena kvaliteta i životne sposobnosti semena kukuruza nakon prajminga

Good crop establishment is essential for achieving high yield and constraints to good establishment include untimely sowing and low seed quality combined with various adverse growing conditions after sowing. Seed priming is a pre-sowing technique used for the improvement of germination, reduction of the time from sowing to emergence and improvement of emergence uniformity. Various seed priming techniques, such as hydropriming and priming with zinc, are used nowadays to improve crop establishment. The importance of seed priming with zinc for better germination, improved stand establishment, and higher maize yield are well documented. However, there is still a lack of results on the effects of seed priming with water and zinc on seed quality and viability, given that maize seed can be kept in storage for many years without a significant reduction in germination. The study was aimed to evaluate the effects of seed priming with water and Zn on the quality and viability of the maize seed. In order to evaluate the response of four maize hybrids to priming with water (hydropriming) and 4 mM zinc sulphate, primed seeds were subjected to laboratory tests, namely to the germination test, the cold test, and the accelerated aging test. Both priming treatments increased the seed quality, but the beneficial effect of Zn-priming maintained to a larger extent than hydropriming in cold-treated and aged seeds. The negative effects of hydropriming on the viability o f the aged seed of hybrid NS 4023 imply a possible limitation to deferred sowing of primed maize seed.

Responsiveness of buckwheat varieties to foliar applications by microfertilizer under forest steppe of the volga region

The yields of modern intensive varieties of buckwheat in arid regions are highly susceptible to adverse hydrothermal growing conditions. The selection of optimal compositions and technologies for using modern agrochemicals that provide an adaptogenic effect and a favourable vegetation regime of plants can be an effective way to stabilize the grain production of this warm-loving but the drought-resistant crop. Scientists have poorly studied these issues and the issues of efficient use of mineral nutrition resources in buckwheat. They studied the responsiveness of buckwheat varieties, that differ in the morphological and biological characteristics of plants, to the foliar application by Yara concentrated complex water-soluble fertilizers containing macroand microelements.The data obtained indicate the presence of varietal specificity, which manifests itself to varying degrees of plant responsiveness to foliar application in the formation of leaf area, grain yield and quality indicators of the crop. The authors made conclusions about the preferred dates for foliar application with the studied Yara complex micronutrient fertilizers. When the foliar application of microelements in the phase of the beginning of grain formation, the K-850 cultivar had the highest yield and the best quality parameters of grains. For the K-899 cultivar, the application in the russeting phase was most effective for grains and affected the best plumpness of the grains. The more powerful morphological potential of Batyr plants was not realized by an adequate increase in yield for the performed feeding. The authors observed a slight tendency to decrease the crude protein content in grains during the foliar application which is probably due to the inverse correlation of this trait with the formation rate of the organic mass of plants.

Water and radiation use efficiencies in maize: Breeding effects on single-cross Argentine hybrids released between 1980 and 2012

Water deficit has been signaled as an important determinant of grain yield (GY) gaps between potential and actual GYs. Breeding for improved water as well as solar radiation productivities is a sustainable means to reduce this gap. The aim of this study was to evaluate breeding effects on GY and its physiological determinants, including water (WUE) and radiation (RUE) use efficiencies, of temperate maize hybrids grown under a wide range of environmental conditions in Argentina. We hypothesized that breeding focused on GY performance and broad adaptation produced an increase in crop biomass linked to an increased tolerance to adverse growing conditions, a trend associated with an increase in WUE and/or RUE. For this purpose, hybrids were grown under three stand densities and eight environmental conditions in the main target environment for the production of temperate hybrids in Argentina. Analyzed traits were GY, total shoot biomass (BT) production, harvest index (HI = GY/BT), crop evapotranspiration (ETC), crop radiation interception (IPARC: cumulative amount of intercepted incident photosynthetically active radiation), radiation use efficiency (RUE = BT/IPARC), water use efficiency (WUE) for biomass production (WUEB,ETc= BT/ETC) and WUE for GY production (WUEGY,ETc= GY/ETC). No breeding effect was registered on ETC and IPARC, whereas significant breeding effects (P < 0.05) were detected on GY (0.5 % YOR−1 from 1980 onwards). The latter were due to the improvement of BT (from 1993 onwards) as well as of HI (between 1980 and 1993), with gains of 0.5 % YOR−1 in both cases. Mentioned trends were associated with a significant increase in RUE (0.7 % YOR−1 from 1993 onwards) and consequently in WUEB,ETc (0.6 % YOR−1 from 1993 onwards) and WUEGY,ETc (0.5 % YOR−1 from 1980 onwards). Results demonstrated that breeding efforts, which have been driven almost exclusively by GY improvement, had no evident effect on the crop water use but had clear effects on crop biomass production and its partitioning. These unintended positive effects of breeding on RUE and WUEs are welcome on a global scale, considering that predicted trends of increasing human demand for water will require increased water productivity rather than increased water use by crops.

A WRKY transcription factor, FtWRKY46, from Tartary buckwheat improves salt tolerance in transgenic Arabidopsis thaliana

The WRKY transcription factor family includes plant-specific transcription factors that are widely involved in plant biotic and abiotic stress responses, growth and development. Tartary buckwheat is a type of small grain with strong resistance to adverse growing conditions. No systematic exploration of the WRKY family in Tartary buckwheat has yet been reported. In this paper, we report the FtWRKY46 gene from Tartary buckwheat and study its role in salt tolerance. FtWRKY46 has transcriptional activation activity in yeast, and FtWRKY46 fused to yellow fluorescent protein localizes to the nucleus. Further studies have found that its transcriptional activation region is located at the N-terminus. A yeast one-hybrid assay indicated that FtWRKY46 could bind to a W-box and activate reporter gene expression. Similarly, transient cotransfection showed that FtWRKY46 could specifically bind to W-box regions and activate reporter gene expression in plants. Furthermore, ectopic expression of FtWRKY46 could enhance Arabidopsis tolerance to salt stress. More specifically, the seed germination rate, root length, chlorophyll content and proline content were significantly higher in transgenic plants ectopically expressing FtWRKY46 than in WT plants after salt stress (P < 0.05), while MDA levels were significantly lower than in WT plants (P < 0.05). Additionally, salt treatment increased the expression of stress-related genes. To summarize, our results suggest that ectopic expression of FtWRKY46 enhance the stress tolerance of transgenic plants by modulating ROS clearance and stress-related gene expression.

МОРФОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА ПЕЧЕНИ И КИШЕЧНИКА КАРПА ПРИ ИСПОЛЬЗОВАНИИ ОПОКИ В КАЧЕСТВЕ ДОБАВКИ К КОРМУ

The paper investigates the effect of adding to the feed a natural sorbent gaize with concentration of 3% and 6% on fish-biological indicators and morphofunctional state of liver and intestines of scaly cyprin Cyprinus carpio (Linnaeus, 1758). The research was carried out in the innovation center “Bioaquapark - Scientific and Technical Center for Aquaculture” under Astrakhan State Technical University. Feeding of yearlings (0+) of scaly carp was carried out in 3 versions: in one control group and two experimental groups (adding 3% and 6% gaize). It has been stated that adding gaize to combined feed increased the survival rate of individuals from 90 to 100%. The increase in body weight was 53% in the test variant and 11% in the second variant. The morphological picture of carp liver in the control and both experimental groups didn’t differ significantly. There were also no foci of inflammation and pathological changes in the structure of the intestine. The research results prove the possibility of using gaize as an additive in carp diet. The best results were obtained when using 3% mineral feed additive. Inclusion of sorbents in the formulation of feedstuffs increases the resistance of fish to adverse growing conditions, prevention of diseases and producing high-quality and environmentally friendly aquaculture products, as well as significantly reduces the cost of fish products.

Recombinant expression of osmotin in barley improves stress resistance and food safety during adverse growing conditions.

BackgroundAlthough many genetic manipulations of crops providing biofortified or safer food have been done, the acceptance of biotechnology crops still remains limited. We report on a transgenic barley expressing the multi-functional protein osmotin that improves plant defense under stress conditions.MethodsAn Agrobacterium–mediated technique was used to transform immature embryos of the spring barley cultivar Golden Promise. Transgenic barley plants of the T0 and T1 generation were evaluated by molecular methods. Transgenic barley tolerance to stress was determined by chlorophyll, total protein, malondialdehyde and ascorbate peroxidase content. Methanol extracts of i) Fusarium oxysporum infected or ii) salt-stressed plants, were characterized by their acute toxicity effect on human dermal fibroblasts (HDF), genotoxicity and affection of biodiversity interactions, which was tested through monitoring barley natural virus pathogen–host interactions–the BYDV and WDV viruses transmitted to the plants by aphids and leafhoppers.ResultsTransgenic plants maintained the same level of chlorophyll and protein, which significantly declined in wild-type barley under the same stressful conditions. Salt stress evoked higher ascorbate peroxidase level and correspondingly less malondialdehyde. Osmotin expressing barley extracts exhibited a lower cytotoxicity effect of statistical significance than that of wild-type plants under both types of stress tested on human dermal fibroblasts. Extract of Fusarium oxysporum infected transgenic barley was not able to damage DNA in the Comet assay, which is in opposite to control plants. Moreover, this particular barley did not affect the local biodiversity.ConclusionOur findings provide a new perspective that could help to evaluate the safety of products from genetically modified crops.

Limitations at the Limit? Diminishing of Genetic Effects in Norway Spruce Provenance Trials.

Provenance trials are used to study the effects of tree origin on climate-growth relationships. Thereby, they potentially identify provenances which appear more resilient to anticipated climate change. However, when studying between provenance variability in growth behavior it becomes important to address potential effects related to site marginality in the context of provenance trials. In our study we focus on provenance-specific climate sensitivity manifested under marginal growth conditions. We hypothesized that the provenance effects are masked if trials are located at marginal environmental conditions of the natural species distribution. Under this framework, we investigate 10 Norway spruce provenances growing at two contrasting locations, i.e., a relatively drought-prone site in western Poland (at the climatic margin of Norway spruce’s natural distribution) and a mild and moist site in north-eastern Poland (within its natural range). Combining principal component analysis with climate-growth relationships, we found distinguishable growth patterns and climate correlations among provenances. That is, at the mild and moist north-eastern site, we observed provenance-specific growth patterns and thus a varying drought susceptibility. In contrast, at the dryer western site, provenance-specific growth patterns were less pronounced and all provenances expressed a common and strong sensitivity to drought. Our results indicate that the genetic specificity of growth reactions diminishes toward the distributional margins of a given species. We conclude that the climate conditions at the margins of a species’ distribution are constraining tree growth independently of tree origin. Because of this, the marginality of a site has to be considered when evaluating climate sensitivity of provenances within trials. As a consequence, the yet different responses of provenances to adverse growing conditions may synchronize under more extreme conditions in course of the anticipated climate change.

Cherry production in South Africa: status quo and new initiatives

At present the main production area for cherries in South Africa is situated in the Western Cape Province, which represents about 50% of the total 262 ha that has been planted up to 2016. Previously, production centered around the Highveld region in the eastern Free State. The cherry production areas in the eastern Free State are situated at approximately 28°45’ latitude and 27°45’ longitude and 1650 m a.s.l. The Highveld region is part of the summer-rainfall area, with dry winters and below zero temperatures during winter nights. This decline in production in the Highveld region is mainly due to these adverse growing conditions. Production was also negatively affected by using the too dwarfing ‘Gisela 5’ rootstocks that were not suitable for the shallow and sandy soils. Older orchards on Mahaleb rootstock are still producing good average yields in harsh growing conditions. Current initiatives include the use of more yield efficient rootstocks like ‘Maxma 14’ and the low-chilling scion cultivars from the breeding programs in California, USA. The poor rootability of Mahaleb cuttings in the nursery and the shortages of in vitro propagated rootstocks like ‘Maxma 14’, also tempered the planting of new orchards. This problem was overcome by a mass importation of in vitro ‘Maxma 14’ from Italy, optimising the current availability of nursery trees to increase dramatically from 32,000 to 150,000 trees year-1. These new initiatives will have a positive effect increasing the number of ha in non-traditional cherry growing areas in South Africa, such as the Northern Province as well as in the warmer parts of the Western Cape Province.

Field trials of micropropagated clones of triploid white and grey poplars

In this article we present, for the first time, the results of 20 years field trials of triploid white poplar (Populus alba L.) and grey poplar (Populus x canescens Sm.) clones propagated by in vitro culture in different edaphic conditions (6 clones in total). The soils of the test plots differ in fertility, chemical and physical-chemical characteristics, which had a significant impact on the plants’ capacity for survival, health and growth. Low fertile, dry, acidic sandy loam and sandy soils are the least suitable for cultivating of in vitro micropropagated clones. In this case we had sandy loam soils on glaciofluvial monomineral quartz sands. The response to adverse growing conditions largely depended on the genotypic characteristics of the plants. The grey poplar clone named Hopersky 1 cultivar has shown the highest ecological plasticity as it has broad genetic basis (it is a hybridogenic species and allotriploid).

The Use of Seed Vigour Tests for Predicting Field Emergence

The general aim of this study was to address the problem of seed vigour testing in Acacia senegal and Acacia mellifera) by studying different seed vigour tests and comparing them to identify the most suitable test for each species. The importance of this study lies in the fact that vigour testing measures the percentage of viable seeds in a sample as well as their ability to produce normal seedlings under less than optimum or adverse growing conditions, similar to those occurring in the field. To achieve this objective, a set of laboratory and field tests were conducted for the two Acacia species. Data collected included: The number of seeds per kilogram, germination percentage, seedling shoot length, seedling root length, seedling root wet and dry weight, seedling shoot wet and dry weight. The cutting test, electrical conductivity tetrazolium test and Hiltner test were employed to determine the seed vigour.&#x0D; The results showed that Acacia mellifera had a high electrical conductivity, indicating its low seed vigour. The electrical conductivity of Acacia senegal was equivalent to that of distilled water, indicating that either the seed coat was intact or no ions were leached from the seeds. Comparison of the various tests suggests that Hiltner test is the most accurate” or “reliable”) test for seed vigor.

Economic Impact of Residual Nitrogen and Preceding Crops on Wheat and Canola

Core Ideas Study on the residual effects of preceding crops and past N management on wheat and canola.Initial positive impact of legume preceding crops on net revenue diminished over time.Residual N had positive effects on net revenue, especially at the highest N rate.Annual fertilization based on production capacity of the region gave the best economic results.Dry conditions allow excess N to remain in soil as residual N, reducing the economic risk of fertilizer over‐application. A 6‐yr study was conducted across western Canada to evaluate the residual effects of preceding crops (PCs) and past N rate management on the economics of subsequent wheat (Triticum aestivum L.) and canola (Brassica napus L.). Field pea (Pisum sativum L.), lentil (Lens culinaris Medik.), canola and wheat harvested for grain, and faba bean (Vicia faba L.) grown and harvested for grain or as a green manure were direct seeded in 2009. Canola was seeded in 2010, barley in 2011, and canola again in 2012 with fertilizer N applied at varying rates for each crop. Spring wheat grown in 2013 and canola in 2014, both without N application, were used to determine residual PC and residual N effects. The positive benefit of legume PCs on the annual crop net revenue (NR) of wheat and canola crops diminished over time. Residual N from previously applied N had positive effects on annual wheat NR in 2013, but only the highest application rate contributed significantly to canola NR in 2014. The NR was greatest with an annual fertilization program based on regional production capacity, but under the dry conditions of the Canadian prairies excess N remaining in the soil after crop production could remain in the soil as residual N to be used by following crops. While generally insufficient to optimize crop production, residual N can reduce the economic risk from over‐application of fertilizer if N is not utilized by the crop due to adverse growing conditions in the year of fertilizer application.