Winter Type Research Articles

Statistical analysis of floods in Bohemia (Czech Republic) since 1825

This study focuses on two main rivers of Bohemia (Czech Republic): the Vltava and the Elbe. Flows are determined for the Elbe at Děčín (discharges) and Litoměřice (water stages), and for the Vltava at Prague (discharges). Extreme flows have an important socio—economic impact; hence modelling their occurrence accurately is crucial. We identify the meteorological causes for floods: (a) the winter type due to snowmelt, ice damming, and usually rain, and (b) the summer type due to continuous heavy rains. The amplitude and frequency of floods are analysed using extreme value theory, in a non-stationary context. This allows the determination of the trends of flood features during the instrumental period and their dependence on atmospheric circulation patterns.

RESPONSES OF SOME PROMISING DRY LAND BARLEY LINES TO LEAF STRIPE DISEASE CAUSED BY PYRENOPHORA GRAMINEA ITO & KURIB

Forty-four barley (Hordeum vulgare) dryland promising lines, were tested for their reactions to four isolates of barley leaf stripe disease caused by Pyrenophora graminea in the greenhouse using seed inoculation method, and also in field conditions in four locations, Karaj, Gorgan, Marogheh and Miandoab, using infected seeds of susceptible cultivars as disease spreader. Because of non-conformity of flowering date between spreader and the experimental lines and/ or non-desirable environmental conditions, the disease did not develop uniformly and sufficiently on the materials in field, but in the greenhouse, lef stripe developed up to 100% on emerged seedlings. The lines were grouped into four reaction categories, based on percentage of infected seedlings. Analysis of variance of the data showed that the experimental lines differed in their reactions to the pathogen isolates, as 38% of lines were resistant, 51% moderately susceptible, 9% susceptible and 2% highly susceptible. The most susceptible lines were Pirat 1//Aljer/ceres 362-1-1 IC, T-2 (2R)//Lignee131/Arabia Abiad, Alpha//Gumhuriyet/ Ligkee 131 and Yesevi-93 and the most resistant ones 4697/105//Yea 132 TH/3/ Tipper followed by ICB-100974/Action, Alpha//Sul/Nacta/3/80-5001 and 132TH/Tokak Yia 147. Frequency of resistance reaction among lines with facultative spring and spring growth habit was higher than that of winter type lines. P. graminea isolates differed in pathogenicity at P>1% level based on the mean of percent infection of lines. This indicating physiologic specialization in population of P. graminea.

Detecting variability changes in Arctic total ozone column

To better assess inter-annual variance changes in ozone time series, we study and propose a statistical procedure based on recent advances in wavelet multi-resolution analysis. This approach, novel to the field of ozone analysis, has the advantages of detecting significant changes in variance and of characterizing the distribution of these changes, including not only their timings but also their strengths. As a test case for our method, we study total ozone column time series from the TOMS (Total Ozone Mapping Spectrometer) Version 7 in the Arctic region over the period 1981–1992. This statistical procedure allows us to analyse the well-known winter–spring transition and the inter-annual variability behaviour. For this specific example, two distinct types of winter–spring transition can be clearly identified for the ozone series. As expected from dynamical studies of the vortex evolution, the first type is constituted of the years for which there exists a very abrupt and temporally localized ozone variability change. More precisely, we detect a significant peak in ozone variance at two multi-resolution wavelet levels. The second type is characterized by smooth ozone variance changes over time and space. Moreover, the Arctic vortex breakdown timing seems to occur, on average, 1 month earlier than our detected changes in ozone variability. These results suggest a potential link between these two phenomena.

Treatment of seasonal affective disorder

Seasonal affective disorder (SAD), winter type, is characterized by the regular annual onset of major depressive episodes during fall or winter, followed by spontaneous remission and sometimes hypomanic or manic episodes during spring and summer. SAD is clinically important, since approximately 2–5% of the general population in temperate climates are affected. Since the first description of the syndrome, researchers have made attempts to elucidate the pathophysiological background of SAD. Bright light therapy has been proposed as the treatment of choice for this disorder. However, numerous studies have also investigated suitable psychopharmacological treatments for SAD. This report is aimed to provide an overview on the clinical management and current therapeutic options for SAD.

Seasonal Succession in the Aquatic Insect Community of an Ozark Stream

ABSTRACT We studied the temporal pattern of the aquatic insect assemblage of an Ozark stream by sampling riffle areas every two weeks from early February through late July, 2002. Total richness of the assemblage, for the entire study, was 138 taxa, including 57 from the dipteran family Chironomidae. Richness levels, per sampling period, ranged from the low 40s to the high 50s and were highest in late March through mid-April. Assemblage composition shifted from one dominated by chironomids in the winter and spring to one dominated by mayflies in the late spring and early summer and by caddisflies in summer. EPT richness levels, diversity, biotic index values, and relative abundances of functional feeding groups varied substantially during the study, occasionally even between two-week sampling periods. The data suggested that, for this type of stream, winter and summer are the times of year that the insect assemblage is least dynamic. These periods, despite lower overall community richness, may therefore be more appropriate to compare samples from different locations or years.

Synoptic sea‐level pressure patterns generated by a general circulation model: comparison with types derived from NCEP/NCAR re‐analysis and implications for downscaling

AbstractA principal component analysis (PCA)‐based synoptic typing scheme is used to assess the ability of the Canadian Centre for Climate Modelling and Analysis (CCCma) Coupled Global Climate Model (CGCM2) to reproduce daily mean‐sea‐level (MSL) synoptic patterns and their frequencies for the Pacific Northwest region of North America. Model output for the ‘control’ period 1961–1989 is compared against the climatology based on National Center for Environmental Prediction (NCEP) re‐analysis data. Although CGCM2 is able to reproduce the full range and seasonality of 13 synoptic types it significantly under‐represents three cold types and over‐represents (by about 50%) three warm/wet winter types. This effect is most pronounced in winter months. Differences in frequencies between the CGCM2 runs (1961–1989 climatology and 1990–2100 IPCC SRES ‘A2’ greenhouse gases (GHG) and aerosol forcing scenario) are smaller than the differences between NCEP and CGCM2 synoptic type frequencies for the 1961–1989 control. Unresolved orographic influences and atmosphere‐ocean coupling are cited as possible explanations for model deficiencies. Results suggest that application of CGCM2 output in downscaling studies examining regional impacts should take account of these potential biases. The approach adopted provides a methodology for not only assessing progress in emerging generations of more sophisticated higher resolution General Circulation Models (GCMs) (e.g. CGCM4 is under development), but also choosing the most appropriate model for regional downscaling studies. Copyright © 2006 Royal Meteorological Society.

Biological Control of Sclerotinia Diseases of Rapeseed by Aerial Applications of the Mycoparasite Coniothyrium minitans

Indoor and field experiments were conducted to evaluate the efficacy of applying the mycoparasite Coniothyrium minitans to the aerial parts of rapeseed plants at the flowering stage to control sclerotinia diseases caused by Sclerotinia sclerotiorum. Under controlled conditions, a petal inoculation technique was used to determine the effect of conidial suspensions of C. minitans on suppression of sclerotinia leaf blight. Results showed that C. minitans was effective in inhibiting infection initiated by ascospores of S. sclerotiorum on flower petals by restricting mycelial growth of the pathogen. Suppression of lesion development was related to the conidial concentration of C. minitans, with larger lesions at low concentration (5×103conidia ml−1), but smaller lesions at high concentration (5×104 conidia ml−1 or higher). When C. minitans-treated rapeseed leaves were inoculated with mycelia of S. sclerotiorum, C. minitans failed to prevent infection of leaves, but caused a significant reduction in number of sclerotia produced on the diseased leaves. No significant difference in efficacy was detected between the two isolates of C. minitans, LRC 2137 and Chy-1, on the two rapeseed cultivars, Westar (spring type) and Zhongyou 821 (winter type). Results of field trials showed a significant reduction of stem rot of rapeseed in four (1997, 1999, 2003 and 2004) out of five years by aerial application of C. minitans, compared with controls. No significant difference in suppressive efficacy was observed between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + benomyl (50 μg ml−1) and benomyl (100 μg ml−1) in 2003, and between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + vinclozolin (100 μg ml−1) and vinclozolin (500 μg ml−1) in 2004. Sclerotia of S. sclerotiorum collected from diseased plants in plots treated with C. minitans in 1999, 2000 and 2003, or with C. minitans + benomyl in 2003 were infected by C. minitans at frequencies ranging from 21.3 to 54.5%. This study concludes that aerial spraying of C. minitans is an effective method for controlling sclerotinia diseases of rapeseed.

Water management tasks in the summer polders of the Nemunas lowland

AbstractSurplus water during floods as well as the low level of the soil surface determine the complicated ecological, economic and demographic conditions in the Nemunas delta. Subsequently, it leads to different types and intensity of use of farmland as well as different methods of water regime regulation: summer or winter type polders. The building of 17 summer polders in the 32 500 ha floodplain area was a compromise, seeking to improve farming conditions and maintain the stability of the flood regime and ecology in the delta. Field measurements and mathematical modelling were carried out. As study results have shown, grass yield losses due to flooding depend on the distribution of water levels and flood duration in the summer polders. Relative damage to agriculture is insignificant and makes up only 10–15% of the total amount of flood damage in the Nemunas lowland.The field measurements and hydraulic and mathematical modelling of flow and sediment regime as well as study of flooding and changed farming conditions also show that it is possible to reduce the height of floods and economic and ecological damage. Rearrangement of the system of protective dikes, regulation of the main river canal and water/sedimentation regime with the help of pumping stations, decrease of pollutant migration into the Curonian Lagoon and Baltic Sea, and recreation of natural meadows are important in that case. Copyright © 2006 John Wiley & Sons, Ltd.

Melatonin in mood disorders

The cyclic nature of depressive illness, the diurnal variations in its symptomatology and the existence of disturbed sleep–wake and core body temperature rhythms, all suggest that dysfunction of the circadian time keeping system may underlie the pathophysiology of depression. As a rhythm-regulating factor, the study of melatonin in various depressive illnesses has gained attention. Melatonin can be both a ‘state marker’ and a ‘trait marker’ of mood disorders. Measurement of melatonin either in saliva or plasma, or of its main metabolite 6-sulfatoxymelatonin in urine, have documented significant alterations in melatonin secretion in depressive patients during the acute phase of illness. Not only the levels but also the timing of melatonin secretion is altered in bipolar affective disorder and in patients with seasonal affective disorder (SAD). A phase delay of melatonin secretion takes place in SAD, as well as changes in the onset, duration and offset of melatonin secretion. Bright light treatment, that suppresses melatonin production, is effective in treating bipolar affective disorder and SAD, winter type. This review discusses the role of melatonin in the pathophysiology of bipolar disorder and SAD.

Large deletions within the first intron in VRN-1 are associated with spring growth habit in barley and wheat

Mol Gen Genomics (2005) 273: 54–65 DOI 10.1007/s00438-004-1095-4 O R I GI N A L P A P E R Daolin Fu AE Pe´ter Szu } cs AE Liuling Yan Marcelo Helguera AE Jeffrey S. Skinner Jarislav von Zitzewitz AE Patrick M. Hayes Jorge Dubcovsky Large deletions within the first intron in VRN-1 are associated with spring growth habit in barley and wheat Received: 15 September 2004 / Accepted: 22 November 2004 / Published online: 3 February 2005 Springer-Verlag 2005 Abstract The broad adaptability of wheat and barley is in part attributable to their flexible growth habit, in that spring forms have recurrently evolved from the ancestral winter growth habit. In diploid wheat and barley growth habit is determined by allelic variation at the VRN-1 and/or VRN-2 loci, whereas in the polyploid wheat species it is determined primarily by allelic variation at VRN-1. Dominant Vrn-A1 alleles for spring growth habit are frequently associated with mutations in the promoter region in diploid wheat and in the A genome of common wheat. However, several dominant Vrn-A1, Vrn-B1, Vrn-D1 (common wheat) and Vrn-H1 (barley) alleles show no polymorphisms in the promoter region relative to their respective recessive alleles. In this study, we sequenced the complete VRN-1 gene from these accessions and found that all of them have large dele- tions within the first intron, which overlap in a 4-kb region. Furthermore, a 2.8-kb segment within the 4-kb region showed high sequence conservation among the different recessive alleles. PCR markers for these dele- tions showed that similar deletions were present in all the accessions with known Vrn-B1 and Vrn-D1 alleles, and in 51 hexaploid spring wheat accessions previously shown to have no polymorphisms in the VRN-A1 pro- moter region. Twenty-four tetraploid wheat accessions Communicated by W.R. McCombie D. Fu AE L. Yan AE J. Dubcovsky (&) Department of Plant Sciences, University of California, One Shields Av, Davis, CA 95616, USA P. Szu } cs Agricultural Research Institute of the Hungarian Academy of Sciences, 2462 Martonva´sa´r, Hungary M. Helguera EEA INTA Marcos Jua´rez, CC 21, 2580 Marcos Jua´rez, Argentina J. S. Skinner AE J. von Zitzewitz AE P. M. Hayes Department of Crop and Soil Science and Horticulture, Oregon State University, Corvallis, OR 97331, USA had a similar deletion in VRN-A1 intron 1. We hypothesize that the 2.8-kb conserved region includes regulatory elements important for the vernalization requirement. Epistatic interactions between VRN-H2 and the VRN-H1 allele with the intron 1 deletion suggest that the deleted region may include a recognition site for the flowering repression mediated by the product of the VRN-H2 gene of barley. Keywords Wheat AE Barley AE Vernalization AE VRN-1 AE Allelic variation Introduction Many cereal crops, such as wheat, barley and oat, are divided into spring and winter types based on their growth habit. Winter varieties require an extended per- iod of exposure to cold in order to flower, a process known as vernalization. Vernalization is defined as ‘‘the acquisition or acceleration of the ability to flower by a chilling treatment’’ (Chouard 1960). The physiology of vernalization has been studied extensively in cereals, but only a few genes from this molecular pathway are cur- rently known (Yan et al. 2003, 2004b). In wheat and barley, the determination of the ver- nalization requirement involves an epistatic interaction between the genetic loci VRN-1 and VRN-2 (Takahashi and Yasuda 1971; Tranquilli and Dubcovsky 2000). Positional cloning of these two genes from diploid wheat (Triticum monococcum L., 2n=14, genome A m A m ) re- vealed that VRN-1 encodes a MADS-box transcription factor that is orthologous to the Arabidopsis meristem identity gene APETALA1 (Yan et al. 2003), while the VRN-2 gene codes for a zinc finger-CCT domain tran- scription factor with no clear orthologues in Arabidopsis or rice (Yan et al. 2004b). The VRN-1 gene is dominant for the spring growth habit and it is up-regulated by vernalization in winter lines (Danyluk et al. 2003; Tre- vaskis et al. 2003; Yan et al. 2003), whereas the VRN-2

Songbirds using crops planted on farmland as cover for game birds

We counted songbirds in crops planted on shooting estates specifically for game management purposes on farmland in Britain and elsewhere in Europe. Winter game crops provide cover and feed areas for pheasants Phasianus colchicus and red-legged partridge Alectoris rufa, while summer game crops are designed to provide brood-rearing cover for these species. In central and southern England, 30 plots of winter game crops, either kale, quinoa or cereal up to 2 ha in area, and 30 adjacent arable-field plots, were surveyed for birds up to six times at monthly intervals during the winter 1997–1998. In the Scottish lowlands, six plots of summer game crops up to 4 ha in area, and adjacent arable fields were surveyed in summer 1999 or 2000. The winter game plots contained more than ten songbirds per hectare in most months, while the adjacent arable-field plots contained less than one. In all three winter game crop types, songbird numbers declined significantly in the second half of the winter while numbers in the arable fields did not. Of the 26 species recorded in the winter game crops, 10 have undergone rapid decline over the last 30 years. Considering these declining species alone, the winter game crops still contained more individuals than the adjacent arable fields throughout the winter. Densities in both the kale and quinoa were higher than in the cereal game crop. The six summer game crops sampled in mid-summer contained on average 2.9 songbirds per hectare, while the adjacent arable fields contained 0.4. Of the 14 species recorded in these summer game crops, eight have undergone rapid or moderate declines over the last 30 years. Although winter and summer game crops are planted in relatively small plots and hence concentrate birds, these plots are widely planted and our results suggest that they benefit birds on farmland.

Evaluation of Lupinus albus L. Germplasm for the Southeastern USA

While white lupin (Lupinus albus L.) has potential as a new minor winter crop, adapted germplasm have to be discovered and considerations for cold tolerance, pest resistance, and other traits determined. We evaluated 100 accessions in 1990–1991 and 616 in 1991–1992 at two locations in central Alabama, USA. Twenty‐four seeds per accession were hand sown in an upland area on a Marvyn sandy loam (fine‐loamy, kaolinitic, thermic, Typic Kahapludults) and in a river bottom area on a Wickham fine sandy loam (clayey, kaolinitic, thermic, Typic Rhododults). Backward stepwise and canonical discriminate analysis (CDA) was used to determine which agronomic traits and groups of accessions were most important for adaptation. Accessions were selected for further evaluation and breeding on the basis of survival through physiological maturity in 1990–1991 and on grain yields ≥27.6 g plot−1 (2128 kg ha−1 equivalent) in 1991–1992. The first two canonical discriminate variates (CAN) had Eigenvalues ≥1 and accounted for ≥51% of the total variance for both years. Vernalization type ratings (winter, semiwinter, spring) were most highly correlated (≥0.87) with CAN 1 for both years, so CAN 1 was labeled vernalization type. The continuum for vernalization requirements was represented by CAN 1 in the 1990–1991 data. On the basis of correlations with CAN 2 for both years, earlier flowering of spring types was detrimental to survival. Selection of accessions with cold tolerance proved to be more important than extremely high vernalization requirements in severe winter types. Brown spot leafspot and root rot [caused by Pleiochaeta setosa (Kirchn.) Hughes] were the most prevalent diseases. East and West Mediterranean germplasm comprised >55% of the selections for further testing; these lines were better adapted to the Southeast, while Southwest Asian and North African severe spring types with little or no vernalization requirement were better suited for use in short season areas of the northern USA.

Distribution of MWG699 polymorphism in Spanish European barleys

The STS marker MWG699/TaqI is closely linked to the vrs1 locus and has been proposed as a marker of domestication in barley. This study included 257 cultivated barleys of both two- and six-rowed varieties, mainly from the western Mediterranean region. These included many landraces from the Spanish barley core collection, Moroccan landraces, and a set of accessions from other European countries. Restriction analysis of amplified DNA revealed three alleles, as previously described. Most of the two-rowed entries had the same allele, type K. Six-rowed entries showed both types A and D. Indeed, type D was widespread among Spanish landraces and commercial varieties from central Europe. It was also found in some two-rowed landraces originating from Spain and Morocco. Barleys with the D haplotype were predominantly winter types, whereas the A haplotype was evenly distributed among spring and winter types. These results support the existence of two different genetic sources among six-rowed Spanish landraces.

Identification of a Brassica juncea‐derived recessive gene conferring resistance to Leptosphaeria maculans in oilseed rape

AbstractScreening of 212 spring type Brassica napus lines carrying B genome chromosome additions and introgressions from B. nigra, B. juncea and B. carinata resulted in the identification of one line segregating for resistance to Leptosphaeria maculans (anamorph Phoma lingam) at the seedling (cotyledon) stage. This line was derived from an interspecific hybrid containing the B genome of B. juncea. Trypan blue staining of cotyledons from resistant individuals demonstrated a hypersensitive response which is delayed in plants with intermediate lesion size. Genetic analysis supported the hypothesis of a monogenic recessive inheritance of resistance. The resistance gene, termed rjlm2, is effective in spring and winter type oilseed rape backgrounds against all tested virulent pathotypes, including two isolates which have been shown to overcome two dominant (race‐specific) B genome‐derived resistance genes in B. napus.

P1.024 Venlafaxine XR for depression: Real-world remission data in primary careR. Mora S. Ros M. Garcia-Garcia

Seasonal affective disorder (SAD), winter type, is a condition characterized by the annual recurrence of depressive episodes during fall/winter, alternating with spring/summer euthymia or hypomania. Various neurotransmitters have been implicated in the etiology of SAD, the strongest evidence involving serotonin. Recently, increasing attention has been paid to the potential role of catecholaminergic pathways in the pathophysiology of SAD. We investigated the efficacy and tolerability of reboxetine, a selective noradrenaline inhibitor, in patients with SAD. Eleven out of sixteen patients who were included in a 6-week drug surveillance during winter season experienced full remission of depressive symptoms. Nine patients reported a rapid relief of preexistent severe atypical depressive symptoms within the first treatment week. Reboxetine might therefore be an effective and well-tolerated treatment option for SAD patients. In conclusion, our preliminary results are in line with evidence from recent studies suggesting that catecholaminergic systems might also be involved in the pathophysiology of SAD.

Effect of the 5R(5A) Alien Chromosome Substitution on the Growth Habit and Winter Hardiness of Wheat

The growth habit, ear emergence time, and frost tolerance of wheat/rye substitution lines have been studied in cultivars Rang and Mironovskaya Krupnozernaya whose chromosome 5A is substituted with chromosome 5R of Onkhoyskaya rye. Hybrid analysis has demonstrated that the spring habit of the recipient cultivars Rang and Mironovskaya Krupnozernaya is controlled by dominant gene Vrn-A1 located in chromosome 5A. Onokhoyskaya rye has a dominant gene for the spring habit (Sp1) located in chromosome 5R. It has been found that the resultant 5R(5A) alien-substitution lines have a winter type of development and ears do not emerge during summer in plants sown in spring. The change in growth habit has been shown to be related to the absence of the rye Spl gene expression in the substitution lines. The winter hardiness of winter 5R(5A) alien-substitution lines has been studied under the environmental conditions of Novosibirsk. Testing the lines in the first winter demonstrated that their winter survival is 20-27%. The possible presence of the frost resistance gene homeoallelic to the known genes Fr1 and Fr2 of the common wheat located on chromosomes 5A and 5D, respectively, is discussed.

Effects of Winter and Summer Forage Type on Pasture and Feedlot Performance and Carcass Characteristics by Beef Steers

An experiment was conducted over 2 yr to evaluate the effects of winter and summer forage type on pasture and feedlot performance and carcass traits of beef steers. British (Angus × Hereford) crossbred steers (113 steers, initial BW = 249 ± 28 kg, yr 1; 98 steers, initial BW = 227 ± 27 kg, yr 2) were stratified by BW and randomly assigned to graze either winter wheat (WW) or dormant native range (NR). Subsequently, steers were randomly assigned to one of five summer treatments: 1) NR, 2) ‘Jose’ tall wheatgrass (TW), 3) ‘Ironmaster’ old world bluestem (BLU), 4) ‘Hardie’ bermudagrass in combination with alfalfa and TW (COMB), and 5) high-concentrate finishing diet. Steers that grazed summer pastures were finished on a high-concentrate diet in the fall. In yr 1, BW gain per hectare was similar for steers grazing WW and NR; in yr 2, steers grazing WW produced greater gain per hectare than NR steers (year × winter treatment, P<0.05). Average daily gain from summer grazing was greater (P<0.01) for steers that had grazed WW in yr 1, but, in yr 2, ADG from steers that had grazed WW was less (P<0.05) compared with the ADG from steers that had grazed NR. In the feedlot, previous winter grazing treatment had no effect on DMI and DMI:ADG in yr 1, but, in yr 2, steers that grazed NR in winter had less (P<0.05) finishing DMI and DMI:ADG. In yr 1, steers that were finished on a high-concentrate diet during summer had greater (P<0.05) finishing ADG, less (P<0.05) DMI:ADG, and less (P<0.05) final BW compared with steers that grazed summer pastures and were finished in the fall. In yr 2, steers finished during summer had greater (P<0.05) DMI and DMI:ADG than did steers that were finished after summer grazing, but final BW were not different. Summer pasture type did not influence finishing performance in yr 1, but differences were observed in yr 2. Wintering steers on NR or WW at a low ADG resulted in compensatory growth during the summer grazing period. However, finishing steers during summer after a low rate of winter gain resulted in less DMI:ADG in the feedlot compared with the system of summer grazing and fall finishing. If growth is not restricted in winter, compensation during grazing is not achieved, and, therefore, summer grazing is of no benefit.

RFLPs in Cultivated Barley and Their Application in the Evaluation of Malting Quality Cultivars

Molecular markers provide powerful tools for characterizing plant genetic resources for crop improvement purposes. A set of 182 barley cultivars representing six different countries were surveyed for restriction fragment length polymorphisms (RFLPs) using 45 clones distributed over all seven barley chromosomes. Polymorphism was detected with every clone, by the use of at least one restriction enzyme per clone (referred to as a locus), and up to 12 alleles were detected per RFLP locus. RFLP patterns were compared among different barley groups formed by subdividing the samples on the basis of country of origin, spring or winter growth habit, and two- or six-rowed spikes. The results indicated that genetic differentiation among different geographical groups was more profound than between spring and winter types, followed by differences between two- and six-rowed barley. Application of the RFLP information to the evaluation of genetic variation in barley cultivars from the United Kingdom indicated a significantly reduced level of molecular polymorphism among malting barley, especially among spring malting lines. It was suggested that the incorporation of exotic germplasm may be desirable in malting barley breeding programs in order to reduce the vulnerability of the crop.

Size and composition of the weed seedbank after 7 years of different cover‐crop‐maize management systems

SummaryThe objective of this study was to obtain detailed information on the long‐term weed suppression potential of four winter soil cover types included in an arable crop system managed at various input levels. We used weed seedbank size and composition to assess weed suppression potential. A field experiment was established in 1993 as a split‐split‐plot design with four replications, including two tillage systems [a conventional system (CS) including ploughing in the cover crops and a low‐input system (LIS) including no tillage with surface mulching of the cover crops] in the main plots, three mineral nitrogen fertilization rates for the main crop in the sub‐plots and four soil cover types (main crop residue, rye, crimson clover and subterranean clover) in the sub‐sub‐plots. Seedbank sampling took place in winter 2000/01. The weed seedbank was analysed with the seedling emergence method. Data were analysed using anova and multivariate techniques. Results indicated that the seedbank density in the LIS was about five times higher than in the conventional input system. In the CS, use of a rye cover crop resulted in a lower seedbank density with respect to the crop residue treatment (−25%), whereas in the LIS the subterranean clover cover crop decreased weed seedbank density as compared with the other cover crops and the crop residue treatment (−22% on average). Differences in species composition were mainly related to tillage system. Implications for cover crop management and the development of sustainable cropping systems are discussed.

Autumn growth and development of different winter oilseed rape variety types at three input levels

The autumn growth and development was studied in three types of winter oilseed rape varieties (line, hybrid and genetically modified hybrid) at three technologies (intensity, standard and low input). Technologies were different by soil preparation before sowing, sowing rate, chemical treatment levels, growth regulation and fertilisation. It is evident from the autumn period 1999&amp;ndash;2002, that the yield of biomass and roots in the autumn period was influenced by the technology and year conditions (water soil condition). The occurrence of surface soil clods influenced negatively the creation of root and aboveground biomass irrespective of the soil cultivation (ploughing or cultivation without ploughing). Also the excessive soil moisture negatively influenced the root and aboveground biomass and increased the differences among variants. The low input variant was substantially worse than intensity and standard. The dry mass of aboveground and root biomass was statistically different (alfa = 0.05) in the intensive and standard variant in comparison with the variant without ploughing (low input). No statistically significant differences were found in the mass of aboveground and root biomass (alfa = 0.05). The percentage of dry mass in aboveground and root biomass was statistically significantly higher (alfa = 0.05) in intensity of growth regulator application tebuconazole (Horizon 250EW) + chlormequat-chloride (Retacel Extra R68) compared with standard and low input. The diameter of root neck, length of roots and number of leaves was statistically the highest (alfa = 0.05) in the intensive variant. Statistically the values differed from the standard and low input variants. Substantially lower differences were found in the varieties in the same characters. GM hybrid showed a lower heterosis effect and the studied characters did not reach the level of unmodified hybrid level.