Production Of Red Clover Research Articles

Effectiveness of Commercial Red Clover (Trifolium pratense L.) Products for the Treatment of Symptoms in Menopausal Women—A Narrative Review

Red clover (Trifolium pratense L.) is found in southeast Europe and Anatolia. Its primary traditional medicinal use includes the treatment of various conditions of the upper respiratory tract. In recent years, its isoflavones have become the focus of research aimed at developing treatments to alleviate menopausal symptoms. Reduced levels of circulating estrogen due to reduced ovarian function can cause short-term symptoms such as hot flashes, palpitations, difficulty sleeping, headaches, fatigue, mood disorders and reduced concentration but also long-term chronic conditions, such as cardiovascular disease, accelerated weight and bone mass loss, atrophic vaginitis, osteoporosis, and cognitive impairment. The aim of this narrative review was to analyze the effects of commercially available and standardized red clover extracts on menopausal women. Eight randomized controlled trials on a total of 8769 menopausal women (aged 40 to 65 years) evaluated the effect of red clover isoflavone extract on menopausal symptoms. In all studies, isoflavone extract treatment showed improvement in all menopausal symptoms, including some common comorbidities, namely, hot flashes (1487 women, 25%), blood lipids (1155 women, 19%), atherosclerosis (6938 women, 79%), risk of breast cancer and endometrial cancer (428 women, 5%), osteoporosis and osteopenia (555 women, 6%), and menopause-related cognitive impairment (3530 women, 40%).

Assessing Yield, Biomass Production, and Forage Quality of Red Clover (Trifolium pratense L.) in Agroforestry System: One-Year Study in Szarvas, Hungary

This study examines the impact of line spacing (X: 24 m, Y: 9 m, Z: 6.5 m) and orientation to tree lines on the growth, yield, and quality of red clover (Trifolium pratense L.) in a temperate, irrigated agroforestry system (2 ha) in Szarvas, Hungary. Three sampling locations were distinguished between the east and west oriented tree lines: the north (N) side, middle (M) strip, and south (S) side of the tree lines. The highest red clovers were observed in the 6.5 m spacing (mean height 69.3 ± 7.2 cm), although yields were similar across 24 m, 9 m, and 6.5 m spacings (2.9 t ha−1, 2.3 t ha−1, and 2.7 t ha−1 dry matter, respectively). Orientation significantly influenced all forage quality parameters, with the north side showing earlier developmental stages and higher proportions of immature flowers (41–59%). Managing the spatial arrangement of red clover in agroforestry systems can help optimize forage quality by mitigating variations in plant maturity.

Relationship of seeding rate to biological nitrogen fixation and seed production of red clover in Saskatchewan

In Saskatchewan, red clover is often grown for seed production. However, there is no recognized or data supported seeding rate for seed production of red clover in Saskatchwan. The objectives of this study were to identify an optimal seeding rate for seed production and biological nitrogen fixation (BNF) and to examine their relationships under semi-arid conditions. This experiment was conducted under field conditions using six different seeding rates (0.5, 2.5, 4.5, 6.5, 8.5 and 10.5 kg ha-1) at Melfort and Clavet, SK in 2018 and 2019, and seed yield, biomass, plant density, and BNF were measured. In our study, red clover was able to compensate for the range of seeding rates between 2.5 and 10.5 kg ha-1 without seed yield loss and BNF reduction, whereas biomass production and BNF were higher at 4.5 kg ha-1 seeding rate than in 0.5 kg ha-1 at Melfort, but no seeding rate effects were found at Clavet. Regardless of location, biomass was always positively correlated with BNF. However, no association was found between seed yield and BNF. Our results suggest that 4.5 kg ha-1 is ideal for seed production, BNF and biomass production of red clover in Saskatchewan.

Preparation of a water-soluble molybdenum(VI) complex with nitrilotriacetic acid and monoethano-lamine. Molecular structure of triammonium [trioxo(nitrilotriacetato)molybdate] monohydrate (NH4)3[MoO3L]·H2O. Application of its solution to increase the productivity of red clover.

Preparation of a water-soluble molybdenum(VI) complex with nitrilotriacetic acid and monoethano-lamine. Molecular structure of triammonium [trioxo(nitrilotriacetato)molybdate] monohydrate (NH4)3[MoO3L]·H2O. Application of its solution to increase the productivity of red clover.

Red clover productivity under drought: Are soil microbes a burden or a treasure?

Drought-induced changes in plant traits are well-studied, e.g. building smaller and thicker leaves, reducing stomatal density or increasing root uptake. However, the extent to which these changes depend on plant-soil interactions remains unclear. Mutualistic soil microbes like arbuscular mycorrhizal fungi (AMF) and Rhizobium are known to enhance plant productivity, water and nutrient uptake and stress tolerance. Therefore, alterations in soil microbial loads are expected to affect not only plant productivity but also plant responses to drought through changing plant traits. In this study, we investigated the effects of plant-soil interactions on the productivity and traits of red clover (Trifolium pratense L.) under repeated drought. We conducted a pot experiment with two treatments: water treatment (wet versus drought) and microbial reduction by soil steam sterilization (native versus sterilized soil). We found that plants in native soil showed lower productivity and plant traits associated with slow-growing strategies (i.e. small and coarse leaves, lower stomatal density and higher root mass). However, the reduction of soil microbial load by soil steam sterilization increased plant productivity under wet conditions and led to plant traits associated with fast-growing strategies. Drought in sterilized soil decreased productivity, promoted earlier wilting and resulted in the development of plant traits associated with a more slow-growing strategy. Furthermore, roots became longer and thinner and rhizobial nodulation decreased, demonstrating the reduction of mutualists. Hence, our results show that soil microbes trigger plant traits, which suggests that they play an important role in plant responses to drought, in maintaining plant productivity and in prolonging plant vitality.

Productivity of Red Clover (Trifolium pratense L.) in Various Ways of Use in Soil and Climatic Conditions of the Western Region of Ukraine

Red clover (Trifolium pratense L. ) is a perennial plant of the legume family (Fabaceae). It is grown both in pure culture and in crops with perennial grasses. This study aims to assess the yield of red clover for hay (two cuttings) and pasture (four slopes) use in the soil and climatic conditions of the Western region of Ukraine. The subject of the study is four breeding numbers created by hybridization and selection methods. The placement of variants is systematic in a sequential arrangement of repetitions in several tiers. Field experiments were carried out over three years (2018–2020) in competitive variety testing. The study found that, on average, the period from regrowth to slope ripeness lasted 67–95 days, from regrowth to pasture ripeness (30–61 days), and from regrowth to economic ripeness of seeds (136–172 days), depending on the years of cultivation. With the hay use of red clover, the yield is 41.14–44.78 t/ha, with the pasture 50.18–52.38 t/ha.

Phenotypic variation and quantitative trait loci for resistance to southern anthracnose and clover rot in red clover.

High variability for and candidate loci associated with resistance to southern anthracnose and clover rot in a worldwide collection of red clover provide a first basis for genomics-assisted breeding. Red clover (Trifolium pratense L.) is an important forage legume of temperate regions, particularly valued for its high yield potential and its high forage quality. Despite substantial breeding progress during the last decades, continuous improvement of cultivars is crucial to ensure yield stability in view of newly emerging diseases or changing climatic conditions. The high amount of genetic diversity present in red clover ecotypes, landraces, and cultivars provides an invaluable, but often unexploited resource for the improvement of key traits such as yield, quality, and resistance to biotic and abiotic stresses. A collection of 397 red clover accessions was genotyped using a pooled genotyping-by-sequencing approach with 200 plants per accession. Resistance to the two most pertinent diseases in red clover production, southern anthracnose caused by Colletotrichum trifolii, and clover rot caused by Sclerotinia trifoliorum, was assessed using spray inoculation. The mean survival rate for southern anthracnose was 22.9% and the mean resistance index for clover rot was 34.0%. Genome-wide association analysis revealed several loci significantly associated with resistance to southern anthracnose and clover rot. Most of these loci are in coding regions. One quantitative trait locus (QTL) on chromosome 1 explained 16.8% of the variation in resistance to southern anthracnose. For clover rot resistance we found eight QTL, explaining together 80.2% of the total phenotypic variation. The SNPs associated with these QTL provide a promising resource for marker-assisted selection in existing breeding programs, facilitating the development of novel cultivars with increased resistance against two devastating fungal diseases of red clover.

Seed Production of Red Clover (Trifolium pratense L.) under Danish Field Conditions

High and stable seed yield is critical for red clover (Trifolium pratense L.) seed production and the commercial exploitation of the crop. A three-year experiment was conducted from 2013 to 2015 under Danish field conditions to explore the influence of precipitation during peak flowering on the seed yield of three red clover cultivars. We investigated the flowering duration and intensity based on a visual scale assessment, seed yield, and thousand seed weight in all three experimental years. In 2014 and 2015 we measured the seed yield components of floret number per flower head, seed number per flower head, and seed set. During the experimental period, high seed yields of more than 1000 kg ha−1 were obtained for the diploid cultivars ‘Rajah’ and ‘Suez’. Although a relatively high seed yield of 500 kg ha−1 was obtained in the tetraploid cultivar ‘Amos’, this was only around half of the seed yield and seed set of the diploid cultivars. Precipitation during peak flowering positively influenced the seed yield and thousand seed weight for the three cultivars. We conclude that observations of flowering phenology are required to determine the impact of environmental conditions on seed yield in red clover cultivars. Further, adequate water supply during peak flowering is important to obtain the high seed yield of red clover.

Effect of Attractants and Micronutrient Biofortification on the Yield and Quality of Red Clover (Trifolium pratense L.) Seeds

The aim of the research was to develop an innovative technique in the seed production of red clover. The research was carried out in 2013–2016, in Felin (51°22′ N, 22°65′ E), in a dependent arrangement (split-split-plot) in four replications. The first order factor was the use of an attractant: (1) control object, with pure water spraying, (2) attractant used in the 60 BBCH phase, (3) attractant applied twice—in the 60 and 65 phase, in the BBCH scale. The factor of the second order was fertilization: (a) standard object with PK fertilization; (b) fertilization with microelements (B + Mo) against the background of constant PK fertilization. The use of attractant ‘Pollinus’ preparation in the cultivation of red clover, both once and twice, in the form of spraying on plants, contributed to an increase in the seed yield, number of heads, share of seeds in the head, thousand seeds weight, and seed germination capacity, compared to the control object. Elements of the red clover yield structure achieved more favorable values with foliar feeding (B + Mo) compared to the standard one. Under the influence of plant biofortification with boron and molybdenum, the number of seeds infected with fungal pathogens and abnormally germinating decreased.

THE PHENOTYPIC FEATURES OF RED CLOVER (TRIFOLIUM PRATENSE L.) THAT CORRELATE WITH SEED PRODUCTIVITY

To reduce the time of the selection process when creating varieties of red clover (Trifolium pratense L.) with a high seed yield, it is necessary to use the source material with the features that positively correlate with an increased seed productivity. It is estimated that in the Northern part of the Central Black Earth Economic region of the Russian Federation the seed productivity of red clover has a high correlation with the weight of the dried mass, a number of stems, inflorescences, seeds in the flowers, seed setability, inflorescence dissemination and a short сorolla tube. The average correlation coefficient was found between the seed yield productivity (1000 seeds), the length of the stem and the full visibility of the leaf pattern. A lesser degree positive correlation was found between seed productivity and a number of beans in the flower, two-seeded beans, a number of internodes, the length of time from the beginning of the spring regrowth and up to the anrhesis. The research has revealed the correlations between the seed productivity and economic, biological, and morphological characteristics of red clover in the Northern part of the Black Earth Economic region of the Russian Federation, and the North Caucasus region, in particular in the Oryol Oblast and North Ossetia-Alania, where this crop occupies a leading position among the cultivated perennial herbs. It is used In biological farming at the hayfields and pastures. It was found that the seed productivity of the red clover as an individual plant is largely determined by the capacity of its development there was a high correlation between the seed yield and the dried mass of the plant (r = 0.72). The plants with the largest number of stems were characterized by the highest seed yield, which was inherent in both diploid and tetraploid cultivars (r = 0.61-0.79 and r = 0.55-0.83, respectively). The seed productivity of plants depended on the number of productive flowers on the plant (r = 0.57-0.78 for diploids and r = 0.76-0.89 for tetraploids) and their mass (r = 0.84). There is a lesser degree correlation between seed productivity and the number of beans in the flower (r = 0.12-0.18 for diploids and r = 0.04-0.16 for tetraploids). To a much greater extent, seed productivity depended on the number of seeds in the flowers (r = 0.79-0.81 for diploids and r = 0.63-0.86 for tetraploids). For the yield of tetraploid seeds, not only the total content of seeds in the flowers is important, but also the number of developed seeds (r = 0.84-0.89), since a significant part of the set seeds dies at various stages of ontogenesis and is removed during the sorting process. Seed productivity of red clover was largely determined by seed setability (r = 0.66-0.77 for diploids and r = 0.49-0.76 for tetraploids) and inflorescence dissemination (r = 0.71-0.80 for diploids and r = 0.70-0.75 for tetraploids). The seed productivity of red clover was associated with a mass of 1000 seeds. For diploid cultivars, this connection was mostly weak (r = 0.24-0.32), for tetraploids - average, which is due to larger seeds (r = 0.39-0.45). As for diploid cultivars, the presence of a weak correlation between seed productivity of the two-seeded beans (r = 0.09-0.18) and the number of stem internodes (r = 0.14) was found. The presence of an average correlation of the seed productivity with the full visibility of the leaf pattern (r = 0.30) was also noted.

Урожайность клевера лугового в зависимости от агроклиматических условий Среднего Урала

Исследования по влиянию климатических условий на урожайность зелёной массы клевера лугового проведены в ФГБНУ «УрФАНИЦ УрО РАН» в 2007–2019 годах на тёмно-серой лесной тяжелосуглинистой почве. Целью данного исследования было выявление зависимости урожайности клевера лугового от климатических условий и последействия разных фонов удобрений в полевом севообороте. Анализ потенциальной продуктивности клевера и его ресурсной средообразующей роли осуществлён на основании полученных данных в трёх последних ротациях с 2007 по 2019 год в зернотравяном севообороте: 1. однолетние травы, поукосно рапс; 2. ячмень с подсевом клевера; 3. клевер 1-го года пользования; 4. пшеница; 5. овёс. В исследованиях применены три фона питания: 1. без удобрений (контроль); 2. минеральный фон (с применением умеренных доз минеральных удобрений из расчёта N30Р30К36 на каждый гектар севооборотной площади. Из 13 лет исследований большинство лет (77%) были умеренно влажными и влажнымми, а 23% — жаркими и засушливыми. При одногодичном использовании клевера основным лимитирующим фактором являлась влажность. Урожайность клевера зависела больше от степени увлажнения: максимальный сбор зелёной массы (25–30 т/га) получен при гидротермическом коэффициенте за вегетационный период более 1,1. В меньшей степени урожайность клевера зависела от последействия удобрений. При переходе от минерального к органоминеральному фону питания наблюдалась небольшая тенденция увеличения урожайности клевера лугового. Прибавка от внесения удобрений под покровную культуру во влажные годы не превышала 25%, что говорит о возможности возделывания клевера на окультуренных почвах без применения минеральных удобрений. Основную массу клевер формировал в первом укосе. Из 13 лет исследований вследствие засушливых условий дважды — в 2010 и 2012 годах — второй укос не сформировался, а после перезимовки 2016–2017 годов клевер полностью выпал. Урожайность первого укоса находилась в прямой корреляционной зависимости от степени увлажнения и в обратной — от суммы положительных температур. Investigations were conducted at the Ural Federal Agrarian Research Center of the Ural branch RAS in 2007–2019. They focused on the effect of environment on green mass yield of red clover. Soil — dark grey with high clay content. The aim was to test the correlation between red clover productivity and weather conditions under different nutrient status in crop rotation. The data was collected from three crop rotations: 1. Annual grasses, postcut rapeseed; 2. clover overseeded into barley; 3. fist-year clover; 4. wheat; 5. oats. Most years (77%) were moderately humid and humid, 23% — hot and arid. Humidity influenced clover yield the most. The highest yield of green mass (25–30 t ha-1) occurred when hydrothermic coefficient exceeded 1.1. Fertilizers had less effect on crop performance. Combination of organic and mineral fertilizers slightly improved clover productivity. Yield increase reached 25% after cover crop fertilization in humid years indicating the irrelevance of clover cultivation on a mineral background. Clover yielded the best in the first cut. In 2010 and 2012 clover regrew poorly due to dry weather. In 2016–2017 clover did not germinate after winter. The first cut yield positively correlated with humidity and negatively — with mean daily temperature.

Effect of Pythium oligandrum and poly-beta-hydroxy butyric acid application on root growth, forage yield and root diseases of red clover under field conditions

Root diseases of red clover (Trifolium pratense L.) contribute to reduced persistence and production of sown red clover stands; however, the potential of biological control of these diseases has not yet been investigated. Our objectives were to determine the effect of application of Pythium oligandrum and poly-beta-hydroxy butyric acid on (i) plant density and root morphology development, (ii) relationships between root branching and plant root disease score and (iii) forage yield and yield components of red clover in a three-year field experiment. Two red clover varieties (Start and Callisto) were established and managed under cutting (3 cuts per year) with four treatments: untreated control; spraying of poly-beta-hydroxy butyric acid (Albit); or application of P. oligandrum (Polyversum) at two intensities. Each autumn, plants were evaluated for root morphology traits and scored for root diseases. Forage dry matter yield, compressed stand height and stem density were evaluated in each cut. Effects on root discoloration were visible only in the last year of the experiment where significantly lower disease score was detected for both Polyversum treatments (4.58) compared with untreated control (4.94). In that year, Polyversum application at the higher intensity promoted increased tap-root diameter (+4%), root branching (+27%), stand height (+13%) and forage yield (+18%) in comparison with the control treatment. Improved forage yield was associated with plant growth stimulation more than from protection against Fusarium. Relationships among root traits and aboveground biomass highlight the need for evaluation of the effects of biological control of forage legumes considering root disease occurrence, together with root morphology traits and forage yield. This study demonstrated a potential of P. oligandrum for improving red clover yield, but optimization of application timing is necessary for determination of practical recommendations and economic efficiency.

Влияние абиотических факторов на семенную продуктивность клевера лугового (Trifolium pratense L.) в условиях субарктической зоны РФ

Field experiments on sod-podzolic medium-loamy soil typical for the Northern region of the Russian Federation were carried out to identify the dependence of seed productivity of red clover varieties on 
 abiotic conditions. Meteorological conditions during the years of research (2012–2018) were different and had a significant effect on seed productivity of clover. It is established that the seed productivity of red clover has a positive correlation with the temperature regime and a negative relationship with rainfall, which indicates the possibility of seed growing of this culture in the study zone. However, seed yield varied considerably from year to year and ranged from 96 to 403 kg/ha. The reasons for the reduction of seed production in some years were varied and complex. As a result of researches it is revealed that for formation of productivity of seeds of a clover more than 150 kg/ha conditions are necessary: sum of effective temperatures above 1400 °С, the hydrothermal coefficient less than 1.6. From 7 years of research conditions close to those in the Northern zone of clover sowing were 57%. The most plastic samples by seed productivity were selected: Taezhnik, K-44933, K-48009, K-1809, K-1040.

Реакция клевера лугового тетраплоидного на срок и способ уборки семенного травостоя

Timely and qualitative harvesting is an important stage of red clover seed growing. The choice of harvesting method is determined by the crop, the state of seed grass and weather conditions during the harvesting period. Field experiments were carried out in 2013-2016 on sod-podzolic medium-loamy soil of the Udmurt Republic. The seed productivity of tetraploid red clover Kudesnik in dependence on the period and method of harvesting was studied: a single-phase harvesting with the browning of 75-80% of the heads; a single-phase harvesting with the browning of 90-95% of the heads (control); desiccation during the browning of 75-80% of the heads, single-phase harvesting; two- phase harvesting with the browning of 75-80% of the heads (control); two-phase harvesting with the browning of 9095% of the heads. In conditions of cool and wet growing seasons of 2014 and 2015 the highest seed yield of tetraploid red clover Kudesnik (140.0 and 209.0 kg / ha) was obtained during the single-phase harvesting with pre-desiccation of crops in the phase of 75-80% of brownish heads. In a relatively warm and dry conditions of 2016 seed productivity of tetraploid red clover more depended on the method of harvesting than on its date. On the average over the three years the highest yields of clover seeds (152.1 kg/ha) have been provided by carrying out of a single-phase harvesting with pre-desiccation of crops in the phase of 75-80% of brownish heads at formation of grass stand with the following parameters: the number of heads - 1087 pcs. /m 2 , seed weight per head - 0.023 g, mass of 1000 seeds - of 2.66 g. The productivity of head had the greatest influence on the formation of seed yield of clover Kudesnik. During the years of investigation only 6-9 pieces of seeds were formed in the head. Laboratory germination of the resulting seeds of red clover was at the level of 90-94%. Seed yield of red clover Kudesnik had the average correlation with the number of seeds in the head r = 0.40), as well as with seeds weight per head (r = 0.48). The energy efficiency ratio at carrying out of a single-phase harvesting with pre-desiccation of crops in the phase of 75-80% of brownish heads was 3.36, profitability level was 234%.

Effect of sowing methods and sowing rate in organic seed production of timothy (Phleum pratense L.), meadow fescue (Festuca pratensis Huds.) and red clover (Trifolium pratense L.)

ABSTRACTDifferent sowing methods and sowing rates were evaluated in organic seed production of timothy (two trials), meadow fescue (two trials) and red clover (one trial) in Southeast Norway, during 2010–2013. The plan included: (1) broadcast sowing of grass/clover, cover crop sown at 12 cm row distance; (2) sowing of cover and seed crop in crossed rows, both at 12 cm row distance; and (3) sowing of cover crop and seed crop in every other row. The three sowing rates were 5, 10 and 15 kg ha–1 in timothy and meadow fescue and 3, 6 and 9 kg ha–1 in red clover. On average for sowing rates and all trials with timothy, meadow fescue and red clover, first year’s seed yields were 5–6%, 20–25% and 19–25% higher on plots sown with cover crop and seed crop in every other row than on plots where seed crop had been broadcast or sown perpendicularly to the cover crop. The different sowing methods had no effect on weed coverage or weed contamination in the cleaned seed. Increasing sowing rate usually had a negative influence on seed yield, while weed coverage/contamination was not significantly affected. It is concluded that organic seed crops should be established with cover crop and seed crop in every other row at a low sowing rate. However, in an organic production system, even this favorable method will not always be sufficient to meet the requirement for seed crop purity.

Assessment of red clover (Trifolium pratense L.) productivity in environmental stress

Assessment of red clover (Trifolium pratense L.) productivity in environmental stress

Productivity and Level of Weed Infestation of Legume Meadow Grasses Depending On Grass Species and Fertilization

The experiment was conducted in the period of 2013-2015 in the experimental field of RIMSA-Troyan. The influence of bio-fertilizers, such as boron humate and molybdenum humate at doses of 1600 ml/ha, was studied. They were applied in the beginning of bud-formation period on legumes, such as bird's-foot-trefoil, sainfoin, and red clover. The highest positive effect of studied bio-fertilizers over productivity was found in the treatment of grassland of sainfoin. Its yield increased, after the application of boron humate, in comparison with the control by 8.3%, and molybdenum humate increased the productivity of red clover by 4.0%. Both bio-fertilizers showed a negative effect in relation to dry matter yield of bird's-foot trefoil. Foliar treatment with boron and molybdenum humate of bird's-foot-trefoil, red clover and sainfoin decreased the level of weed infestation of crops and had an influence over the biological characteristics of grass species and meteorological conditions. As a result of the influence of bio-fertilizers, the stem height of sainfoin and red clover increased, which had a favorable influence over productivity of their grasslands.

Field Abundance Patterns and Odor-Mediated Host Choice by Clover Seed Weevils, Apion fulvipes and Apion trifolii (Coleoptera: Apionidae).

The clover seed weevils Apion fulvipes Geoffroy, 1785 and Apion trifolii L., 1768 (Coleoptera: Apionidae) cause major losses to seed production of white clover (Trifolium repens L.) and red clover (Trifolium pratense L.), respectively. Clover is important as animal forage and an alternative to inorganic fertilizers. Because clover is mainly pollinated by bees, the use of insecticides in management of these weevils is discouraged. To gain basic knowledge for development of alternative management strategies, we investigated weevil field abundance over two growing seasons, as well as feeding and olfactory host preferences by A. fulvipes and A. trifolii. Field trap catches in southern Sweden revealed that white clover was dominated by A. fulvipes and red clover by A. trifolii. For both weevil species, female catches were positively correlated to the number of clover buds and flowers in the field. In feeding and olfactory bioassays, females of A. fulvipes and A. trifolii showed a preference for T. repens and T. pratense, respectively. However, the feeding preference was lost when the antennae were removed, indicating a significant role of olfaction in host choice. Male weevils of both species did not show clear olfactory or feeding preferences for host plant species. The field study and laboratory bioassays demonstrate that, at least for female weevils, olfaction is important for selection of host plants. We discuss these novel results in the context of managing these important pests of clover by exploiting olfaction and behavioral attraction to host plant volatiles.

Productivity and nitrogen benefits of late-season legume cover crops in organic wheat production

Cicek, H., Entz, M. H., Thiessen Martens, J. R. and Bullock, P. R. 2014. Productivity and nitrogen benefits of late-season legume cover crops in organic wheat production. Can. J. Plant Sci. 94: 771–783. When full-season cover crops are used in stockless organic rotations, cash crop production is compromised. Including winter cereals in rotations can widen the growing season window and create a niche for late-season cover crops. We investigated the establishment and biomass production of relay-cropped red clover (Trifolium pratense L.) and sweet clover (Melilotus officinalis L. ‘Norgold’) and double-cropped cowpea (Vigna unguiculata L. ‘Iron and Clay’), hairy vetch (Vicia villosa L.), lentil (Lens culinaris L. ‘Indianhead’), soybean (Glycine max L. ‘Prudence’), pea (Pisum sativum L. ‘40-10’), and oil seed radish (Raphanus sativus L.) as well as wheat response to these crops under reduced tillage (RT) and conventional tillage (CT) at three locations in Manitoba, Canada. Red clover, sweet clover and pea produced from 737 to 4075 and 93 to 1453 and 160 to 2357 kg ha−1of biomass, respectively. All double crops, with the exception of soybean at 2 site years, established successfully under both RT and CT. The presence of cover crops increased wheat N uptake at stem elongation, maturity and yield, even when the biomass production of cover crops was modest. We conclude that late-season cover crops enhance the following wheat yield and facilitate reduced tillage in organic crop production.

Differences in Yield of Diploid and Tetraploid Red Clover in Lithuania

The research was carried out in 2003-2011 at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry. The fresh forage, dry matter (DM) and seed yields of red clover diploid and tetraploid populations and cultivars were determined. In total 58 diploids and 35 tetraploids were evaluated during four cycles in the study period. The average DM yield of diploids was 16.6 t ha -1 and of tetraploids was 17.8 t ha -1 . The tetraploid average DM yield surpassed that of diploids by only 6.5%. The seed yield was very low over the period. The average seed yield of diploids was 110.4 kg ha -1 . The average seed yield of tetraploids was 94.9 kg ha -1 . The diploid average seed yield was higher than that of tetraploids by 16.3%. The highest negative impact on seed yield was due to wet weather in the seed harvest year, which was favourable for development of diseases on above-ground plant parts. The study showed that tetraploid red clover had no significant advantage over diploid red clover in DM yield under Lithuanian conditions. Variation in seed yield showed that production of diploid red clover seed is less problematic. It seems that only directed disease resistance breeding can improve seed yield as well as forage yield of red clover.