Winter Type Research Articles

Población expuesta a inviernos fríos en México

En esta investigación se analiza el impacto de la estación fría del año que prevalece en extensas regiones montañosas del país y expone a sus pobladores a las bajas temperaturas invernales que afectan su salud y su economía. Es un estudio interdisciplinario que evalúa la distribución de la población afectada por inviernos fríos y muy fríos a escala municipal, en una extensa región que es identificada desde el punto de vista climatológico. En el 2000 la numerosa población afectada por este fenómeno representó 69% del total nacional, ubicada en 22 entidades federativas agrupadas en dos áreas una al norte y otra al centro del país. En los mapas realizados se muestra la distribución de la población, en cuatro tipos de invierno clasificados por su duración e intensidad, según el número de meses fríos en los que se manifiesta la marcada disminución de la temperatura.

High-density mapping of the earliness per se-3Am (Eps-3A m ) locus in diploid einkorn wheat and its relation to the syntenic regions in rice and Brachypodium distachyon L.

In temperate grasses, such as wheat (Triticum sp.) and barley (Hordeum vulgare L.), earliness per se (eps) is defined as the intrinsic difference in flowering time of fully vernalized plants grown under long day conditions. The main task of our investigations was to confirm and refine the chromosomal position of the previously mapped Eps-3Am locus in einkorn wheat (Shindo et al. in Genome 45:563–569, 2002; Hori et al. in Breed Sci 57:39–45, 2007). To this end, 110 recombinant inbred lines (RILs) were phenotypically and genotypically evaluated. The population had been obtained from a cross between an early flowering X-ray mutant KT3-5 (T. monococcum L.) of cultivated spring type and a wild wheat line KT1-1 of T. boeoticum Boiss. (winter type). Heading time evaluations under greenhouse conditions resulted in a 10-day difference (P = 0.008) between the mapping parents and a range of 49 days for the RIL population. Quantitative trait locus analyses of heading time, anthesis time, spikelet number and spike length showed the best linkage with marker loci close to the telomeric region of the long arm of chromosome 3A. The highest LOD values for heading time, anthesis time, spikelet number and spike length were 5.96, 5.40, 3.33 and 5.10, respectively (LOD threshold 2.0, P < 0.05). Linkage analysis of 51 molecular markers delimited the new Eps-3Am interval to 0.9 cM, including 14 newly developed markers using collinearity with rice (Oryza sativa L.) and Brachypodium distachyon L. The present study marks a further step towards the molecular elucidation and functional analysis of Eps-3Am in wheat and other small grain cereals.

Yield performance of late-maturing winter canola (Brassica napus L.) types in the High Rainfall Zone of southern Australia

Area and production of canola (Brassica napus L.) in the High Rainfall Zone (HRZ) of southern Australia has increased significantly over the past decade. Varieties available to growers have not been bred specifically for the HRZ and are generally adapted to the drier regions of the cropping belt. Field experiments were conducted at Hamilton in south-west Victoria in 2005, 2006 and 2008 to identify canola traits and management suited to the HRZ of southern Australia. Nine varieties with different reported maturities (winter and spring types) were sown at either two times of sowing and/or under different nitrogen (N) fertiliser regimes. Dates of key phenological development were recorded, dry matter was determined at bud, flowering and maturity and grain yield and yield components were determined at harvest. Plant traits and climate data were assessed in relation to grain yield. Yields of the winter types were either significantly (P &lt; 0.05) greater or not significantly less than the spring types in all 3 years and similar to those reported under experimental conditions in Europe. This was despite the winter types flowering up to 35 days later than the spring types and spring rainfall being approximately half that of the long-term average. In general, the winter types had greater early vigour, greater dry matter production at the bud, flowering and maturity stages and were taller than the spring types. Regression analysis showed positive relationships between grain yield and pod density and plant size (dry matter and plant height). Plant size was influenced by variety, time of sowing and N fertiliser application rates. Crops in the HRZ were able to sustain more seeds per pod at larger canopy sizes and pod densities than those achieved in the northern hemisphere. Despite the number of pods per g of dry matter at flowering being nearly double that reported in the UK, there was little apparent reduction in the number of seeds per pod. It is possible that higher solar radiation and warmer minimum temperatures in the HRZ of Australia provide conditions more favourable for growth before, and during grainfill. This indicates that different dry matter production and yield component targets may be appropriate for canola in this environment especially in more typical seasons. It is likely that growers will need to sow new, later maturing varieties earlier and with higher rates of N fertiliser than is current practice in Australia. This study indicates that winter types may have the potential to provide improvements to the yield of canola in the HRZ either through the direct importation of varieties from overseas or through the identification and incorporation of desired traits into existing material. It is recommended that a wider range of germplasm be assessed over a greater geographical area to identify traits and management practices to optimise phenology and canopy structure. This information can be used to help inform breeders on crop improvement priorities as well providing tailored management practices to maximise grain yields for this environment.

Genetic Diversity of Rapeseed Accessions from Different Geographic Locations Revealed by Expressed Sequence Tag‐Simple Sequence Repeat and Random Amplified Polymorphic DNA Markers

ABSTRACTGenetic diversity information will be very valuable for future rapeseed (Brassica napus L.) improvement. The genetic diversity and relationships among 92 rapeseed accessions, including 44 from China, 22 from Europe, 16 from the United States, and 10 from Canada, were assessed by 60 random amplified polymorphic DNA (RAPD) and 22 expressed sequence tag (EST)‐simple sequence repeat (SSR) primers. In total, 618 RAPD and 117 EST‐SSR polymorphic fragments were detected. The average number of polymorphic fragments found by each RAPD primer was 10.3 ranging from 3 to 17 and that detected by each pair of EST‐SSR primer was 5.3 ranging from 4 to 7. The unweighted pair‐group method with arithmetic mean (UPGMA) cluster analysis revealed that these 92 accessions could be classified into three major clusters. Cluster I consisted of accessions mainly from China, which belong to the semi‐winter type. Cluster II contained accessions from Europe and the United States, which belong to the winter type. Cluster III was a semi‐winter and spring type mixture group, which contained accessions mainly from China and Canada. The principal component analysis and population structure analysis revealed similar results to the cluster analysis. Analysis of molecular variance result based on four geographic groups indicated that genetic variation was 8.24% among populations of geographic regions and 91.76% within geographic regions. Rapeseed accessions from the United Stated have the greatest genetic distance from accessions of other geographic origins, especially those from China. United States rapeseed could be important germplasm resources for enriching the genetic background of Chinese rapeseed and vice versa.

Genetic diversity among melon accessions (Cucumis melo) from Turkey based on SSR markers

Melon (Cucumis melo) is an important vegetable crop in Turkey, where it is grown in many regions; the most widely planted lines are local winter types belonging to the var. inodorous. We examined 81 melon genotypes collected from different provinces of Turkey, compared with 15 reference melon genotypes obtained from INRA/France, to determine genetic diversity among Turkish melons. Twenty polymorphic primers were used to generate the SSR markers. PCR amplification was performed and electrophoresis was conducted. SSR data were used to generate a binary matrix. For cluster analysis, UPGMA was employed to construct a clustering dendrogram based on the genetic distance matrix. The cophenetic correlation was compared with the similarity matrix using the Mantel matrix correspondence test to evaluate the representativeness of the dendrogram. A total of 123 alleles were amplified using the 20 SSR primer sets. The number of alleles detected by a single primer set ranged from 2 to 12, with an average of 6.15. The similarity ranged from 0.22 to 1.00 in the dendrogram developed from microsatellite analysis. Based on this molecular data, we concluded that genetic diversity among these Turkish accessions is relatively high.

A mutation screening platform for rapeseed (Brassica napus L.) and the detection of sinapine biosynthesis mutants

We developed two mutant populations of oilseed rape (Brassica napus L.) using EMS (ethylmethanesulfonate) as a mutagen. The populations were derived from the spring type line YN01-429 and the winter type cultivar Express 617 encompassing 5,361 and 3,488 M(2) plants, respectively. A high-throughput screening protocol was established based on a two-dimensional 8× pooling strategy. Genes of the sinapine biosynthesis pathway were chosen for determining the mutation frequencies and for creating novel genetic variation for rapeseed breeding. The extraction meal of oilseed rape is a rich protein source containing about 40% protein. Its use as an animal feed or human food, however, is limited by antinutritive compounds like sinapine. The targeting-induced local lesions in genomes (TILLING) strategy was applied to identify mutations of major genes of the sinapine biosynthesis pathway. We constructed locus-specific primers for several TILLING amplicons of two sinapine synthesis genes, BnaX.SGT and BnaX.REF1, covering 80-90% of the coding sequences. Screening of both populations revealed 229 and 341 mutations within the BnaX.SGT sequences (135 missense and 13 nonsense mutations) and the BnaX.REF1 sequences (162 missense, 3 nonsense, 8 splice site mutations), respectively. These mutants provide a new resource for breeding low-sinapine oilseed rape. The frequencies of missense and nonsense mutations corresponded to the frequencies of the target codons. Mutation frequencies ranged from 1/12 to 1/22kb for the Express 617 population and from 1/27 to 1/60kb for the YN01-429 population. Our TILLING resource is publicly available. Due to the high mutation frequencies in combination with an 8× pooling strategy, mutants can be routinely identified in a cost-efficient manner. However, primers have to be carefully designed to amplify single sequences from the polyploid rapeseed genome.

Population structure revealed by different marker types (SSR or DArT) has an impact on the results of genome-wide association mapping in European barley cultivars

Diversity arrays technology (DArT) and simple sequence repeat (SSR) markers were applied to investigate population structure, extent of linkage disequilibrium and genetic diversity (kinship) on a genome-wide level in European barley (Hordeum vulgare L.) cultivars. A set of 183 varieties could be clearly distinguished into spring and winter types and was classified into five subgroups based on 253 DArT or 22 SSR markers. Despite the fact, that the same number of groups was revealed by both marker types, it could be shown that this grouping was more distinct for the SSRs than the DArTs, when assigned to a Q-matrix by STRUCTURE. This was supported by the findings from principal coordinate analysis, where the SSRs showed a better resolution according to seasonal habit and row number than the DArTs. A considerable influence on the rate of significant associations with malting and kernel quality parameters was revealed by different marker types in this genome-wide association study using general and mixed linear models considering population structure. Fewer spurious associations were observed when population structure was based on SSR rather than on DArT markers. We therefore conclude that it is advisable to use independent marker datasets for calculating population structure and for performing the association analysis.

Association of Fhb1 and Qfhs.ifa-5A in Spring versus Winter Growth Habits in Bread Wheat (Triticum aestivum L.)

Fusarium head blight (FHB) is a major disease that reduces grain yield and quality of winter and spring wheat in eastern South Dakota. This study was conducted to determine the association of FHB resistance QTLs (Fhb1 and Qfhs.ifa-5A) to spring and winter growth habits of bread wheat. Four genotypes consisting of susceptible winter wheats ‘Nekota’ and ‘2137’ and moderately resistant spring wheats ‘ND2710’ and ‘BacUp’ were crossed and populations derived from the crosses were separated into spring and winter types following cold treatment of seedlings at -70C for 1 h. A total of six SSR markers (Fhb1 markers: Xgwm389, Xgwm493 and STS256; Qfhs.ifa-5A markers: Xgwm293, Xgwm304 and Barc186) were used to genotype the populations. A chi-square analysis deviating from a 1:1 ratio showed that there were significant differences in the percentage of genotypes containing homozygous marker alleles for Fhb1 and Qfhs.ifa-5A between spring and winter types in the population ND2710/2137, ND2710/Nekota and BacUp/2137. The percentage of genotypes with homozygous marker alleles for Fhb1 was lower in the spring types in the populations ND2710/2137 and ND2710/BacUp. In contrast, the spring types in the population ND2710/Nekota had a higher percentage of genotypes containing homozygous marker alleles for Qfhs.ifa-5A compared with the winter types. The results indicated that Fhb1 was not necessarily associated with the spring growth habit; whereas, Qfhs.ifa-5A was not necessarily associated with the winter growth habit.

Response of spring type wheat (Triticum aestivum L.) cultivars to different chilling treatments

Late sowing of wheat in autumn due to environmental conditions or late harvesting of cotton crop results in substantial yield loss. It may be attributed to non-fulfillment of chilling requirements. The present study was conducted to identify the chilling requirement of autumn sown cultivars of wheat. Effect of chilling treatment (measured in vernalization days (VDs)) on seven wheat cultivars (five Pakistani and two American) was observed by exposing the seedlings to 6°C for 7, 14, 21, 28 and 35 days that is 6.72, 13.44, 20.16, 26.86 and 33.60 VDs. Seedlings which acted as control were not subjected to chilling treatment. All spring type wheat cultivars headed irrespective of their chilling treatment but increase in VDs, enhanced days to heading. Winter type wheat “Caldwell” did not show heading which indicated its high VDs requirement. Chilling treatment also affected grain yield of all cultivars. Sehar-06 and Marquillo demonstrated highest yields at 6.72 VDs while GA-02, Inqilab-91, Chakwal-50 and Freed-06 manifested highest yields at 13.44 VDs. The results of the experiment revealed that heading time and grain yield of all spring type wheat cultivars is affected by chilling treatments. Depending upon the response of the cultivars and available VDs calculated from temperature data of last 20 years. It is suggested that GA-02, Inqilab-91, Chakwal-50 and Fareed-06 must be sown in mid December while Sehar-06 can be sown in the start of January to meet their chilling requirement under field conditions without substantial yield reduction.

Breeding effects on the genotype × environment interaction for yield of bread wheat grown in Spain during the 20th century

This study evaluates the changes caused by breeding in the genotype × environment interaction of the bread wheat varieties most widely cultivated in Spain during the 20th century. A set of 27 varieties was tested in 8 environments representative of the bread wheat growing areas in the country. Minimum temperature and thermal time from sowing to heading were the main environmental traits determining genotype × environment (GE) interactions for yield. Landraces were the least productive and showed specific adaptation to environments with low minimum temperatures before heading and high relative air humidity after heading. Yield consistency was low in landraces due to large environmental effects on the number of spikes and grain weight. Old-bred varieties (released between 1945 and 1955) were the first step towards breeding for wide adaptation due to the lower dependence of their final spike number and grain weight on water availability during grain filling. Differences in the adaptation pattern of the varieties introduced since the 1960s were caused by their growth habit. Winter types were more widely adapted than spring ones, mostly because they had a more consistent number of grains per spike. Grain weight of winter varieties was enhanced in environments with high relative humidity during grain filling. Spring varieties had more grains per spike in environments with high minimum temperatures and thermal time before heading. The number of grains per spike was the yield component that most closely followed the pattern of adaptation observed for grain yield.

Diversity in the Response to Low Temperature in Representative Barley Genotypes Cultivated in Europe

ABSTRACTBarley (Hordeum vulgare L.) production in many regions is constrained by low temperatures. Numerous screening methods have been proposed for studies of freezing tolerance (FT) and winter hardiness (WH). Here, we compared the response to low temperature of 54 barley genotypes released in Europe. Major components of WH were analyzed in field and growth chamber experiments under different hardening and freezing conditions. Phenotype screening of freezing injury (lethal temperature for 50% of the plants [LT50], plant survival, and chlorophyll fluorescence) and indirect evaluations (molecular‐marker‐based analysis of vernalization requirement) were used. The maximum quantum yield of the photosystem II photochemistry measured as the variable (Fv) to maximal (Fm) fluorescence ratio (Fv:Fm) analysis was confirmed as a reliable method of screening genetic diversity for FT in plants at early growth stages. Variability for FT was also found after shorter acclimation at optimal (3/1°C day/night) or suboptimal (12/7°C day/night) hardening temperatures. High levels of FT and WH were found in both winter and facultative growth habits. Facultative genotypes were more responsive to early hardening than spring or winter types. Some of them coped best with frost in both laboratory and field experiments. The most tolerant winter genotypes coped best with prolonged exposure to low temperature in the field experiments. A conservative estimation of the role of FT in WH implies that at least 50% of WH was associated with the level of FT. A combined analysis using physiological and molecular tools is proposed for phenotyping WH in large populations.

Two Major Resistance Quantitative Trait Loci are Required to Counteract the Increased Susceptibility to Fusarium Head Blight of the Rht‐D1b Dwarfing Gene in Wheat

ABSTRACTFusarium head blight (FHB) is a destructive wheat (Triticum aestivum L.) disease of global importance. The widely used dwarfing allele Rht‐D1b has recently been shown to compromise FHB resistance. The objectives of this study were to investigate the impact of this dwarfing allele in a segregating population with major resistance quantitative trait loci (QTL) derived from ‘Sumai‐3’ and Nobeokabozu, and to determine how many resistance QTL are needed to counteract its negative effect. Fusarium head blight resistance was evaluated in four field trials with spray inoculation and two field trials with point inoculation in a double‐haploid (DH) population from a cross between the Swedish cv. Avle (susceptible spring type; wild‐type allele Rht‐D1a) and Line 685 (resistant winter type; semi‐dwarf allele Rht‐D1b). The Rht‐D1 locus explained up to 38% of the phenotypic variation and was the most important QTL for FHB severity under spray inoculation but did not show any effect after point inoculation. Fhb1 on 3BS was detected with both inoculation methods but was relatively more important after point inoculation. Another two QTL on 5A and 2BL were detected after spray inoculation and a QTL on 2D after point inoculation. Comparison of phenotypic effects of different allele combinations revealed that a combination of both Fhb1 and the 5A QTL was required to counteract the increased susceptibility of Rht‐D1b. Although breeding of FHB resistant cultivars with this dwarfing allele is possible, it requires the pyramiding of several resistant QTL to achieve adequate levels of resistance.

Line tester analysis for seed yield and yield components in spring and winter type varieties of oil seed rape

Line × tester analysis of two testers of spring type and six lines of winter type oil seed rape varieties were used to estimate combining ability and heterosis of yield components and seed yield. Significant mean squares of treatments for yield components and seed yield, indicating significant genetic variations among the genotypes including parents and their crosses. Parents vs crosses mean square which indicate average heterosis was significant for all the traits except pods per plant. Line × tester mean square was significant for all the traits except pods per plant. High narrow sense heritability estimate for 1000-seed weight indicating the prime importance of additive genetic effects for this trait. Significant positive general combining ability (GCA) effects of seed yield were observed for parents which had positive GCA effects of pods per plant. Most of the crosses with significant positive specific combining ability (SCA) effects for pods per plant had significant positive SCA effects of seed yield. Most of the crosses had significant positive over spring parent heterosis of seed yield, indicating winter type of oil seed rape varieties are suitable candidates for improving this trait using combination method. Key words: Heterosis, narrow sense heritability, seed yield, oil seed rape.

Flowering time variation in oilseed rape (Brassica napus L.) is associated with allelic variation in the FRIGIDA homologue BnaA.FRI.a

Oilseed rape (Brassica napus L.) is a major oil crop which is grown worldwide. Adaptation to different environments and regional climatic conditions involves variation in the regulation of flowering time. Winter types have a strong vernalization requirement whereas semi-winter and spring types have a low vernalization requirement or flower without exposure to cold, respectively. In Arabidopsis thaliana, FRIGIDA (FRI) is a key regulator which inhibits floral transition through activation of FLOWERING LOCUS C (FLC), a central repressor of flowering which controls vernalization requirement and response. Here, four FRI homologues in B. napus were identified by BAC library screening and PCR-based cloning. While all homologues are expressed, two genes were found to be differentially expressed in aerial plant organs. One of these, BnaA.FRI.a, was mapped to a region on chromosome A03 which co-localizes with a major flowering time quantitative trait locus in multiple environments in a doubled-haploid mapping population. Association analysis of BnaA.FRI.a revealed that six SNPs, including at least one at a putative functional site, and one haplotype block, respectively, are associated with flowering time variation in 248 accessions, with flowering times differing by 13–19 d between extreme haplotypes. The results from both linkage analysis and association mapping indicate that BnaA.FRI.a is a major determinant of flowering time in oilseed rape, and suggest further that this gene also contributes to the differentiation between growth types. The putative functional polymorphisms identified here may facilitate adaptation of this crop to specific environments through marker-assisted breeding.

Patterns of molecular variation in a species-wide germplasm set of Brassica napus

Rapeseed (Brassica napus L.) is the leading European oilseed crop serving as source for edible oil and renewable energy. The objectives of our study were to (i) examine the population structure of a large and diverse set of B. napus inbred lines, (ii) investigate patterns of genetic diversity within and among different germplasm types, (iii) compare the two genomes of B. napus with regard to genetic diversity, and (iv) assess the extent of linkage disequilibrium (LD) between simple sequence repeat (SSR) markers. Our study was based on 509 B. napus inbred lines genotyped with 89 genome-specific SSR primer combinations. Both a principal coordinate analysis and software STRUCTURE revealed that winter types, spring types, and swedes were assigned to three major clusters. The genetic diversity of winter oilseed rape was lower than the diversity found in other germplasm types. Within winter oilseed rape types, a decay of genetic diversity with more recent release dates and reduced levels of erucic acid and glucosinolates was observed. The percentage of linked SSR loci pairs in significant (r (2)>Q (95 unlinked loci pairs)) LD was 6.29% for the entire germplasm set. Furthermore, LD decayed rapidly with distance, which will allow a relatively high mapping resolution in genome-wide association studies using our germplasm set, but, on the other hand, will require a high number of markers.

Genetic basis of control of Rhynchosporium secalis infection and symptom expression in barley

The genetic basis of several different components of resistance to Rhynchosporium secalis in barley was investigated in a mapping population derived from a cross between winter and spring barley types. Both the severity of visual disease symptoms and amount of R. secalis DNA in leaf tissues were assessed in field trials in Scotland in the 2007/2008 and 2008/2009 growing seasons. Relative expression of symptoms was defined as the residual values from a linear regression of amount of R. secalis DNA against visual plot disease score at GS 50. Amount of R. secalis DNA and visual disease score were highly correlated traits and identified nearly identical QTL. The genetic control of relative expression of symptoms was less clear. However, a QTL on chromosome 7H was identified as having a significant effect on the expression of visual disease symptoms relative to overall amount of R. secalis colonisation.

Low temperature and oxidative stress in cereals

Low temperature stress results in significant yield losses in cereals. Cereals of subtropical origin like maize and rice are severely damaged at temperatures below 10°C and are killed at subzero temperatures. This stress effect is called chilling. In contrast, cereals originating from the temperate zone (wheat, barley, rye and oat) may survive short periods even between −10 and −20°C, depending on the species and varieties, so they are freezing-tolerant to various extents. For the winter type of these cereals a gradual decrease in temperature up to −4°C results in cold acclimation, which increases their freezing tolerance. In addition, it fulfils their vernalization requirement, which is necessary for the correct timing of the vegetative to generative transition. During both chilling and freezing, oxidative stress is induced. Although the accumulation of high concentrations of reactive oxygen species may be lethal, a moderate increase in their level may activate various defence mechanisms. In this review the role of reactive oxygen species, antioxidants, carbohydrates, free amino acids, polyamines and hormones in the response to low temperature stress in cereals will be described. The effect of light and the use of the model plantBrachypodium distachyonL. to reveal the biochemical and molecular biological background of this response will also be discussed.

Spatial variability in large-scale and regional atmospheric drivers of Pinus halepensis growth in eastern Spain

In this study we analyzed the influence of general atmospheric circulation patterns and the frequency of weather types on the spatio-temporal variability of tree-ring growth in Pinus halepensis forests in eastern Spain. Three atmospheric circulation patterns affecting the western Mediterranean region were included in the study: the North Atlantic Oscillation (NAO), the Western Mediterranean Oscillation (WeMO) and the Mediterranean Oscillation (MO). In addition, the particular circulation pattern affecting eastern Spain was quantified using the frequency of weather types. The variability of radial growth (width) of earlywood and latewood in P. halepensis was quantified at 19 sites using dendrochronological methods. Two distinct patterns, reflecting growth variability in the northern and southern areas involved in the study, were identified for both earlywood and latewood tree-ring series. The influence of atmospheric circulation modes on tree growth resembled the spatial patterns identified, as earlywood and latewood formation in northern sites was determined by the NAO variability, whereas the WeMO dominated growth at the southern sites. Winter, summer and autumn weather types also exerted a control over tree radial growth. We conclude that both atmospheric circulation indices and weather types exert significant control on the formation of earlywood and latewood, because of their influence on precipitation patterns. The findings also suggest that wet and mild conditions during winter and the following autumn enhance P. halepensis earlywood and latewood formation, respectively. Thus, winter atmospheric patterns may indirectly influence latewood growth through direct effects on previous earlywood development driven by precipitation variability.

Seasonal symptoms in bipolar and primary care patients

There is evidence of seasonality in bipolar affective disorder (BAD) and the preponderance of atypical symptoms in bipolar depressive episodes is also seen in winter type Seasonal Affective Disorder. Differences in seasonal symptoms between BAD and appropriate comparison populations have been scrutinised only in small studies. Symptoms described on the Seasonal Pattern Assessment Questionnaire (SPAQ) were compared between 183 patients with BAD and 468 patients consulting their general practitioners. Statistical analyses were adjusted for differing age and gender distributions between the two groups. Compared with the general practice patients, subjects with BAD reported greater seasonal fluctuations in mood (p=0.003). On one measure BAD subjects reported increased seasonal changes in social activity (p<0.001) and greater weight fluctuation over the year (p=0.001). The most striking differences were in sleep patterns; BAD subjects slept significantly more throughout the year, and slept for a mean of 1.8h more in winter than in summer (versus a 1.0h difference in the general practice group, p<0.001). Against 20% of the general practice group, 46% of BAD patients rated seasonal changes in well-being to be at least a moderate problem. The SPAQ was designed as a screening instrument for Seasonal Affective Disorder, not for studies of this nature. Some of the reported differences, notably in social activity and weight changes, may reflect secondary psychosocial effects of BAD. Seasonal changes, most notably winter hypersomnia, should be identified in patients with BAD. These symptoms may respond to treatments such as light therapy that are used in recurrent winter depression.

Effectively widening the gene pool of oilseed rape (Brassica napus L.) by using Chinese B. rapa in a ‘virtual allopolyploid’ approach

With 2 figures and 2 tables Abstract Brassica rapa (AA), which has a high level of genetic diversity, has been used to widen the genetic base of oilseed rape (B. napus L., AACC). However, the differences in the degree to which the genetic base of oilseed rape can be widened using different forms of B. rapa have not been well characterized. We used a strategy of virtual allopolyploid to investigate the genetic differences between the A subgenome of natural oilseed rape and different ecotypes of B. rapa. In this strategy, the genetic characteristics of the virtual allopolyploid lines are deduced from the genotypes of the parental lines which are established using molecular markers, without the need for interspecific hybridization. Three genotypes of B. oleracea and 56 accessions of B. rapa which originated from Europe, China and India were genotyped using simple sequence repeat markers, together with nine oilseed rape lines representing spring, semi‐winter and winter types. The genotypes of 168 virtual allopolyploid lines were derived from those of the parental lines and compared with those of the natural oilseed rape lines. Our data revealed that the virtual allopolyploid lines that were derived from Chinese semi‐winter B. rapa showed substantial genetic variation from natural oilseed rape. This indicates that Chinese semi‐winter B. rapa can be used effectively to broaden the germplasm of oilseed rape.