Winter Type Research Articles

Allelopathic effects of aqueous extracts of Avena fatua on seed germination and seedling growth of Triticum aestivum (variety GW-273).

Wheat is an edible grain, one of the oldest and most important of the cereal crops. Though grown under a wide range of climates and soils, wheat is best adapted to temperate regions with rainfall between 30 and 90 cm. Winter and spring wheat varieties are the two major types of the crop, with the severity of the winter determining whether a winter or spring type is cultivated. Avena fatua is a wildly growing weed along with wheat and is a serious competitor (competition in terms of allelochemicals) of wheat. Whole plants of Avena fatua were collected and dried, crushed, mixed with distilled water and allowed to stand for 72 hours in water bath at 25 (±2) degrees followed by filtration using whatman's filter paper no.1. Four concentrations of different ratios were prepared for demonstration of the allelopathic effects on wheat (GW-273) seed germination. The extracts pose significant and varying allelopathic effects on seed germination and other seedling growth parameters.

RORA 유전자 다형성과 기분 및 행동의 계절성 변동의 연관성

목 적 : 일주기 유전자 다형성이 계절성 기분 장애의 발병 기전과 연관이 있다는 여러 연구 결과들이 보고되었다. 본 연구에서는 한국에 거주하는 건강한 성인을 대상으로 RORA (Retinoid-related orphan receptor A)유전자의 다형성과 계절성 변동의 관계를 살펴보고자 하였다. 방 법 : 신문 광고를 통해 모집한 507명의 지역사회 인구를 대상으로 하였다. 기분과 행동의 계절적 변동은 Seasonality Pattern Assessment Questionnaire(SPAQ)를 이용하여 평가하였다. RORA rs11071547 SNP는 PCR을 이용하여 유전자형 분석을 하였다. 여름형은 교란 요소로 작용할 것으로 판단되어, 29명의 여름형은 제외한 총 478명의 대상자를 분석하였다. 계절성군과 비계절성군의 유전자형 분포의 비교는 Chi-square test를 이용하였고, 전반적 계절성 점수(Global seasonality score, GSS)와 RORA rs11071547의 연관성은 ANCOVA로 분석하였다. 결 과 : 연구 참여자 507명 중 12.1%(겨울형 9.3%, 여름형 2.8%)가 SAD에 해당하였다. 계절성군과 비계절성군간의 RORA rs11071547의 유전자형 분포는 통계적으로 유의한 차이는 없었다. 전반적 계절성 점수(GSS)와 세부 항목인 수면시간, 사회활동, 기분, 에너지 수준에서 유의한 차이는 관찰되지 않았다. 그러나 세부 항목 중 체중과 식욕에서는 C 대립유전자 동형접함체군에서 유의하게 점수가 높은 양상을 관찰할 수 있었다(p=0.026, p=0.034). 결 론 : 본 연구에 참여한 대상자들에서 RORA 유전자 다형성이 체중과 식욕의 계절성 변화에 주요한 역할을 하며, 계절성 기분 장애의 감수성과도 어느 정도 연관이 있을 것으로 생각된다. Objectives: Several evidence has been suggested that the circadian gene variants contribute to the pathogenesis of seasonal affective disorder. In this study, we aimed to investigate the polymorphism in RORA (Retinoid-related orphan receptor A) gene in relation to seasonal variations among healthy young adults in Seoul, Korea. Methods: A total of 507 young healthy adult subjects were recruited by advertisement. Seasonal variations were assessed by the Seasonality Pattern Assessment Questionnaire (SPAQ). Single-nucleotide polymorphism in the RORA rs11071547 gene was genotyped by PCR in 507 individuals. Considering summer type as confounding factor, we conducted analysis 478 subjects except 29 subjects of summer type. The Chi-square test was conducted to compare differences between groups of seasonals and non-seasonals. Association between genotypes and Global Seasonality Score (GSS) were tested using ANCOVA (Analysis of covariance). Results: In this sample, the prevalence of SAD was 12.1% (winter type 9.3%, summer type 2.8%). There is no significant difference in genotyping distribution of RORA rs11071547 between groups of seasonals and non-seasonals. Global seasonality score (GSS) and scores of all subscales except body weight and appetite were not significantly different between the group with C allele homozygote and the group with T allele homozygote and heterozygote (p-value 0.138). Scores of body weight and appetite were significantly higher in group with C allele homozygotes. Conclusion: These results suggest that RORA gene polymorphism play a role in seasonal variations in appetite and body weight and is associated with susceptibility to seasonal affective disorder in some degree in the population studied.

Development of High-throughput Molecular Markers for Blackleg (Leptosphaeria maculans) Resistance Genes in Brassica napus for Gene Stacking

Quinta' and 'Glacier' are two important winter type canola cultivars from Europe. 'Quinta' has two independent blackleg resistance gene loci, Rlm1 and Rlm4; 'Glacier' has two other genes, Rlm2 and Rlm3. This study focuses on mapping the resistance genes Rlm1 and Rlm3 using high throughput SRAP (sequence related amplified polymorphism) markers and SNPs. The F2 and F3 populations were constructed with crosses of 'Westar' × 'Quinta' and 'Westar' × 'Glacier'. The populations were screened with the corresponding isolates. The phenotype segregation in the populations supported that a single dominant resistance gene controls the resistance in 'Quinta' and Glacier separately. The closest SRAP marker was identified for the resistance gene in 'Quinta' by using 256 pairs of primers and screening 2,500 polymorphic loci. B342 is 1.5 cM to Rlm1 and 6.8 cM to Rlm3. SNP80870 developed from the N7 orthologous region in Arabidopsis was 3 cM to Rlm3. A population for stacking the three resistance genes (Rlm1, Rlm3 and LepR3) was constructed. Marker screening and disease inoculation were both used for the selection of lines with the three resistance genes.

Effect of vernalization and photoperiod on flax flowering time

Vernalization and photoperiodism are two important physiological processes related to yield of many cool-season annual crops. The flowering response of 20 flax (Linum usitatissimumL.) genotypes to two vernalization regimes (vernalized and unvernalized) and two photoperiod treatments (10 and 14 h) was evaluated in a growth chamber study in 2010 and 2011. The results suggest that photoperiod, vernalization, and genotype all had an effect on earliness as measured by days to anthesis. Unlike flax grown in the Upper US Midwest and Canada, Texas flax is grown in the fall due to high spring and summer temperatures. Genotype interaction was observed with both vernalization and photoperiod. Specifically, flax genotypes from Texas (winter type) were sensitive to both vernalization and photoperiods for flowering. Texas genotypes delayed anthesis for 7 days or more in unvernalized seedlings, whereas flowering time of most other spring grown flax genotypes was unaffected by the vernalization treatments. Texas genotypes also delayed anthesis for 12 days or more under vernalized and short day conditions, whereas most other genotypes were not influenced by photoperiodism in vernalized seedlings. The selection for vernalization and photoperiodic sensitivity in Texas genotypes and introgression of these traits into recently adapted spring grown genotypes is needed for development of high yielding flax genotypes for southern Great Plains production areas.

Nitrogen-metabolism related genes in barley - haplotype diversity, linkage mapping and associations with malting and kernel quality parameters

BackgroundSeveral studies report about intra-specific trait variation of nitrogen-metabolism related traits, such as N(itrogen)-use efficiency, protein content, N-storage and remobilization in barley and related grass species. The goal of this study was to assess the intra-specific genetic diversity present in primary N-metabolism genes of barley and to investigate the associations of the detected haplotype diversity with malting and kernel quality related traits.ResultsPartial sequences of five genes related to N-metabolism in barley (Hordeum vulgare L.) were obtained, i.e. nitrate reductase 1, glutamine synthetase 2, ferredoxin-dependent glutamate synthase, aspartate aminotransferase and asparaginase. Two to five haplotypes in each gene were discovered in a set of 190 various varieties. The development of 33 SNP markers allowed the genotyping of all these barley varieties consisting of spring and winter types. Furthermore, these markers could be mapped in several doubled haploid populations. Cluster analysis based on haplotypes revealed a more uniform pattern of the spring barleys as compared to the winter barleys. Based on linear model approaches associations to several malting and kernel quality traits including soluble N and protein were identified.ConclusionsA study was conducted to investigate the presence of sequence variation of several genes related to the primary N-metabolism in barley. The detected diversity could be related to particular phenotypic traits. Specific differences between spring and winter barleys most likely reflect different breeding aims. The developed markers can be used as tool for further genetic studies and marker-assisted selection during breeding of barley.

Genome-wide association mapping of frost tolerance in barley (Hordeum vulgare L.)

BackgroundFrost tolerance is a key trait with economic and agronomic importance in barley because it is a major component of winter hardiness, and therefore limits the geographical distribution of the crop and the effective transfer of quality traits between spring and winter crop types. Three main frost tolerance QTL (Fr-H1, Fr-H2 and Fr-H3) have been identified from bi-parental genetic mapping but it can be argued that those mapping populations only capture a portion of the genetic diversity of the species. A genetically broad dataset consisting of 184 genotypes, representative of the barley gene pool cultivated in the Mediterranean basin over an extended time period, was genotyped with 1536 SNP markers. Frost tolerance phenotype scores were collected from two trial sites, Foradada (Spain) and Fiorenzuola (Italy) and combined with the genotypic data in genome wide association analyses (GWAS) using Eigenstrat and kinship approaches to account for population structure.ResultsGWAS analyses identified twelve and seven positive SNP associations at Foradada and Fiorenzuola, respectively, using Eigenstrat and six and four, respectively, using kinship. Linkage disequilibrium analyses of the significant SNP associations showed they are genetically independent. In the kinship analysis, two of the significant SNP associations were tightly linked to the Fr-H2 and HvBmy loci on chromosomes 5H and 4HL, respectively. The other significant kinship associations were located in genomic regions that have not previously been associated with cold stress.ConclusionsHaplotype analysis revealed that most of the significant SNP loci are fixed in the winter or facultative types, while they are freely segregating within the un-adapted spring barley genepool. Although there is a major interest in detecting new variation to improve frost tolerance of available winter and facultative types, from a GWAS perspective, working within the un-adapted spring germplasm pool is an attractive alternative strategy which would minimize statistical issues, simplify the interpretation of the data and identify phenology independent genetic determinants of frost tolerance.

УСТОЙЧИВОСТЬ ТРИТИКАЛЕ К ОСНОВНЫМ ВОЗБУДИТЕЛЯМ БОЛЕЗНЕЙ, РАСПРОСТРАНЕННЫМ В СЕВЕРО-ЗАПАДНОМ РЕГИОНЕ РОССИЙСКОЙ ФЕДЕРАЦИИ

The modern triticale varieties have high feed advantages, they have a good tolerance to difficult environments and they are resistant to majority of phytopathogens. For the period of 2005-2006 phytosanitary monitoring for the triticale samples of different ecologo-geographic origin with spring (327 samples) and winter (37 samples) type of development from N.I. Vavilov All-Russian Scientific Research Institute of Plant Growing on the resistance to the basic wheat pathogens of Northwest region of the Russian Federation (brown and yellow rust, wheat leaf blotch, powdery mildew) was carried out. In addition, the authors determine the duration of interphase periods, the height of plants, the mass of 1000 grains. The pathogen of powdery mildew does not develop on samples of triticale. The maximal number of triticale samples, introduced from the European part of the former Soviet Union (Ukraine, Belarus) was characterized by absence of defeat symptoms by brown rust and wheat leaf blotch agents. Pathogenesis of the yellow rust agent was not found on the triticale samples, received from Central Asia, Northern Europe, Australia, South America, Asia and Africa. As was revealed, the greatest degree the attribute of triticale origin influenced on wheat leaf blotch pathogenesis, in the least – on brown and yellow rusts pathogenesis. As was revealed, the criterion of a triticale origin influenced on wheat leaf blotch pathogenesis in the greatest degree, and in the least – on brown and yellow rusts. In the greater degree the plants development type affect the wheat leaf blotch pathogenesis on triticale samples of the Russian selection and in smaller on triticale samples, received from European part of Former USSR, Northern Europe, East Europe, Central Europe.

TRITICALE RESISTANCE TO THE MAIN PHYTOPATHOGENIC ORGANISMS OF NORTHWEST REGION OF THE RUSSIAN FEDERATION

The modern triticale varieties have high feed advantages, they have a good tolerance to difficult environments and they are resistant to majority of phy-topathogens. For the period of 2005-2006 phytosanitary monitoring for the triticale samples of different ecologo-geographic origin with spring (327 samples) and winter (37 samples) type of development from N.I. Vavilov All-Russian Scientific Research Institute of Plant Growing on the resistance to the basic wheat patho-gens of Northwest region of the Russian Federation (brown and yellow rust, wheat leaf blotch, powdery mildew) was carried out. In addition, the authors deter-mine the duration of interphase periods, the height of plants, the mass of 1000 grains. The pathogen of powdery mildew does not develop on samples of triticale. The maximal number of triticale samples, introduced from the European part of the former Soviet Union (Ukraine, Belarus) was characterized by absence of de-feat symptoms by brown rust and wheat leaf blotch agents. Pathogenesis of the yellow rust agent was not found on the triticale samples, received from Central Asia, Northern Europe, Australia, South America, Asia and Africa. As was revealed, the greatest degree the attribute of triticale origin influenced on wheat leaf blotch pathogenesis, in the least – on brown and yellow rusts pathogenesis. As was revealed, the criterion of a triticale origin influenced on wheat leaf blotch pathogenesis in the greatest degree, and in the least – on brown and yellow rusts. In the greater degree the plants development type affect the wheat leaf blotch pathogenesis on triticale samples of the Russian selection and in smaller - on triticale samples, received from European part of Former USSR, Northern Europe, East Europe, Central Europe. Keywords: triticale, cereal crop diseases, leaf rust, yellow rust, wheat leaf blotch, powdery mildew.

Global genetic diversity in oilseed Brassica rapa

Three major simple sequence repeat (SSR) groups were identified in a global collection of 164 oilseed Brassica rapa based on allelic diversity at loci: SSR group 1 (south Asia, predominantly from India, Pakistan, and Nepal); SSR group 2 (predominantly southern and eastern Europe with mostly winter and semi-winter types); and SSR group 3 (northern Europe, mostly from Germany, and many of unknown origin). Nine outliers from several regions were placed in a fourth SSR group, which had the highest allelic diversity per accession of all SSR groups. Analysis of molecular variance of SSR data supported four groups but indicated that genetic variance within populations was high (84%) compared with variance between populations. Flowering habit was classified as winter, spring or semi-winter type, and pollination control as self-incompatible or self-compatible. These phenotypes were distributed across each of the three SSR groups and outliers, although most SSR group 1 accessions were self-compatible spring types, and winter types were mainly from SSR groups 2 and 3. Two SSR sub-groups were present among Indian accessions, both of which contained brown-seeded types, but only one sub-group contained yellow-seeded types (most likely yellow sarson). Eleven B. rapa accessions were misclassified in genebanks as oilseed types but were re-classified as leafy or root vegetable types, and 12 accessions were misclassified as B. rapa and were shown to be allotetraploid or other Brassica species.

Genetic Analysis on Flowering Time and Root System in Brassica napus L

Rapeseed or canola (Brassica napus L.) exhibits both winter and spring growth habit. Vernalization is required to induce flower in the winter type whereas the spring type does not require vernalization to flower. The winter type has a vigorous root system whereas the spring type has a weakly developed root system. The inheritance of flowering time and root system were studied using seven winter parents and three spring parents. Crosses (F1) and reciprocal crosses (F′1) were made between the winter‐ and spring‐type parents. The F1, F′1, and F2 progenies were grown in the greenhouse. The vernalization requirement for flowering was observed as a recessive trait. Significant flowering delays (3–5 d) in F1's of the spring × winter crosses were observed compared with winter × spring crosses. Segregation of flowering time indicated that one major gene is responsible for flower initiation in the population. The F1 and F′1 of winter and spring crosses showed a vigorous root system, indicating the dominant nature of vigorous root system in B. napus. The vigorous root system phenotype was found to be controlled by three genes. Positive and significant correlations were observed between several yield contributing characteristics. Root length showed a positive significant correlation with seed yield per plant for both cross and reciprocal cross whereas dry root weight was not significantly correlated with seed yield. A significant positive correlation was also observed between late flowering vs. root length and late flowering vs. dry root weight. This is the first report on genetics of root system and its contribution to seed yield in B. napus.

Recent Trends of Fire Occurrence in Sumatra (Analysis Using MODIS Hotspot Data): A Comparison with Fire Occurrence in Kalimantan

MODIS (Moderate Resolution Imaging Spectroradiometer) hotspot and precipitation data for the most recent 11-year period (2002 to 2012) were analyzed to elucidate recent trends in the seasonal and spatial fire occurrence in Sumatra and the relationship with precipitation. Using a latitude line of S 0.5°, Sumatra was divided into two regions, N. (north) and S. (south) Sumatra. Different trends in seasonal fire occurrence were discussed and further defined by considering two different precipitation patterns. Analysis of hotspot (fire) data was carried out using 0.5° × 0.5° grid cells to evaluate recent trends of spatial fire occurrence. Analysis results of hotspot and precipitation data were also tallied every 10-day to find the relationship between seasonal fire occurrence and the dry season. Standard deviation (SD) and variance (V) were then used to evaluate fire occurrences in Sumatra and Kalimantan objectively. The relatively mild fire occurrence tendency in Sumatra compared to Kalimantan could be the result of different stages of forest development or the high deforestation rate in Sumatra compared with Kalimantan. This paper also shows that the two different seasonal fire activities in N. and S. Sumatra were closely related to the two different dry season types: a winter and summer dry season type (WD & SD) in N. Sumatra, and a summer dry season type (SD) in S. Sumatra. Extreme fire occurrences in the Dumai region in 2005 and Palembang region in 2006 could be partially explained by a severe drought occurrence enhanced by two different kinds of El Nino events.

Using APSIM to explore wheat yield response to climate change in the North China Plain: the predicted adaptation of wheat cultivar types to vernalization

SUMMARYCultivar selection is a dominant factor in crop production to obtain high yield. While previous studies have evaluated a range of impacts and adaptation of climate change (CC) on crop yield, few studies have focused on evaluating the effectiveness of changing cultivars with different vernalization requirements as an adaptation. In the present study, mean and inter-annual variability of yield were quantified for three winter wheat cultivar types at three ecological sites (Shangzhuang in Beijing, Quzhou in Hebei and Huangfanqu in Henan) in the North China Plain, by linking a crop model and the outputs of Providing Regional Climates for Impacts Studies (PRECIS) for both the baseline (1961–90) and future SRES scenarios A2 and B2 (2070–2100). The results showed that a warming trend prolonged the length of the vegetative growth period of local cultivars through reduced vernalization, generally leading to a negative impact on yield. However, the introduction of cultivars with relatively lower vernalization demands from warmer southern to cooler northern regions could be an effective adaptation strategy to offset the negative impact of climatic change. Adjustment in cultivars increased yield at Shangzhuang and maintained it at Quzhou and Huangfanqu. Elevated CO2 would significantly increase yield in the future with or without considering the sensitivities of the selected cultivars. The inter-annual variability of yield generally increased in the A2 scenario, but decreased in the B2 scenario. Overall, winter wheat with semi-winter types or weak-winter types would grow preferentially, while cultivars with winter types would probably be reduced in future.

Promoter Variation and Transcript Divergence in Brassicaceae Lineages of FLOWERING LOCUS T

Brassica napus (AACC, 2n = 38), an oil crop of world-wide importance, originated from interspecific hybridization of B. rapa (AA, 2n = 20) and B. oleracea (CC, 2n = 18), and has six FLOWERING LOCUS T (FT) paralogues. Two located on the homeologous chromosomes A2 and C2 arose from a lineage distinct from four located on A7 and C6. A set of three conserved blocks A, B and C, which were found to be essential for FT activation by CONSTANS (CO) in Arabidopsis, was identified within the FT upstream region in B. napus and its progenitor diploids. However, on chromosome C2, insertion of a DNA transposable element (TE) and a retro-element in FT upstream blocks A and B contributed to significant structural divergence between the A and C genome orthologues. Phylogenetic analysis of upstream block A indicated the conserved evolutionary relationships of distinct FT genes within Brassicaceae. We conclude that the ancient At-α whole genome duplication contributed to distinct ancestral lineages for this key adaptive gene, which co-exist within the same genus. FT-A2 was found to be transcribed in all leaf samples from different developmental stages in both B. rapa and B. napus, whereas FT-C2 was not transcribed in either B. napus or B. oleracea. Silencing of FT-C2 appeared to result from TE insertion and consequent high levels of cytosine methylation in TE sequences within upstream block A. Interestingly, FT-A7/C6 paralogues were specifically silenced in winter type B. napus but abundantly expressed in spring type cultivars under vernalization-free conditions. Motif prediction indicated the presence of two CO protein binding sites within all Brassica block A and additional sites for FT activation in block C. We propose that the ancestral whole genome duplications have contributed to more complex mechanisms of floral regulation and niche adaptation in Brassica compared to Arabidopsis.

생태형이 다른 귀리품종의 파종기별 조사료 생산성 및 사료가치

Most oats are used for livestock feed in the world. This experiment was conducted at Iksan city of Korea from 2007 to 2008. The objective of this study was to select eminent oat (Avena sativa L.) cultivars with high-yielding and a quality for forage adaptable in each planting seasons. Experimental design was split-plot design with three replications. A split plot design was used with seeding date on the main plots and other treatments fully randomized in sub-plots. A factorial arrangement of treatments included three different ecotypes cultivars, winter type (Sanmhan, Donghan and Chohan), summer type (High-speed, Darkhorse, and Swan), and naked oats near to spring type (Daeyang, Choyang, and Sunyang) and twelve seeding dates (twice a month from March to November). Plant height, dry matter yield, and percent TDN was significantly affected by seeding dates, cultivars, and the interaction of cultivars seeding dates. There was a decrease in plant height, dry matter yield, and percent total digestible nutrients (TDN) as seeding was delayed from early March to late June and it also from early September to early November. The winter type oat cultivars such as Samhan, Donghan, and Chohan adapted to fall seeding and early summer harvest, while summer type cultivars such as High-speed, Darkhorse, and Swan showed high productivity either to summer seeding and mid-fall harvest or to spring seeding and early summer harvest. Naked type cultivars, Choyang and Daeyang, showed high forage yield by spring and summer seeding except for fall seeding because of cold damage. Summer type oat cultivars such as High-speed, Darkhorse, and Swan can supplement high forage production in spring. TDN yield showd the most at seeding in October 10 (780 kg ), followed at seeding in March 23 (627 kg ).

Assessment of Drought Tolerance Indices and their Relation with ISSR Markers in Bread Wheat (Triticum aestivum L.)

Water stress is one of the most important environmental abiotic stress that reduced crop yield especially in arid and semi arid regions of the world. In order to identifying drought tolerance, 39 cultivars of spring, facultative and winter type wheat varieties were planted as subplots within the irrigation plots (main plots) in a randomized complete block design with three replications in a research filed of Faculty of Agriculture, University of Mohaghegh Ardabili, Iran. In 2/3 continuous irrigation stress level, based on stress susceptibility, geometric mean productivity and harmonic indices, ‘Sepahan’, ‘Karaj 3’, ‘Bahar’ and ‘Yavaroos’ were known as the best varieties; and in 1/3 continuous irrigation stress level, based on the mentioned indices, ‘Hirmand’, ‘Bahar’, ‘Yavaroos’ and ‘Marvdasht’ were the best one. According to biplot resulted from principle coordinate analysis, in 2/3 continuous irrigation ‘Moghan 1’, ‘Golestan’, ‘Kavir’, ‘Maroon’, ‘Karkheh’, ‘Chanaab’, ‘10’, ‘6’, ‘Bahar’ and ‘Sepahan’; and in 1/3 continuous irrigation ‘Golestan’, ‘10’, ‘Niknejad’, ‘Maroon’, ‘Darab’, ‘Falat’, ‘Arta’, ‘Marvdasht’, ‘Bahar’ and ‘Hirmand’ were identified as the most tolerant cultivars. According to multiple regression analysis in subject of agronomic traits, 43, 33 and 25 informative ISSR markers identified in control, 2/3 and 1/3 continuous irrigation conditions, respectively. Also among these markers, there were significant relationship between P 12 L 3 and P 21 L 3 markers with plant height and spike length; P 4 L 1 and P 22 L 1 markers with flag leaf length; P 19 L 4 markers and number of node; P 30 L 4 markers and awn length; P 10 L 1 and P 22 L 1 with peduncle to plant height ratio in all of stress and non-stress conditions.

Genome-wide evaluation of genetic diversity and linkage disequilibrium in winter and spring triticale (x Triticosecale Wittmack)

BackgroundRecent advances in genotyping with high-density markers nowadays enable genome-wide genomic analyses in crops. A detailed characterisation of the population structure and linkage disequilibrium (LD) is essential for the application of genomic approaches and consequently for knowledge-based breeding. In this study we used the triticale-specific DArT array to analyze population structure, genetic diversity, and LD in a worldwide set of 161 winter and spring triticale lines.ResultsThe principal coordinate analysis revealed that the first principal coordinate divides the triticale population into two clusters according to their growth habit. The density distributions of the first ten principal coordinates revealed that several show a distribution indicative of population structure. In addition, we observed relatedness within growth habits which was higher among the spring types than among the winter types. The genome-wide analysis of polymorphic information content (PIC) showed that the PIC is variable among and along chromosomes and that especially the R genome of spring types possesses a reduced genetic diversity. We also found that several chromosomes showed regions of high genetic distance between the two growth habits, indicative of divergent selection. Regarding linkage disequilibrium, the A and B genomes showed a similar LD of 0.24 for closely linked markers and a decay within approximately 12 cM. LD in the R genome was lower with 0.19 and decayed within a shorter map distance of approximately 5 cM. The extent of LD was generally higher for the spring types compared to the winter types. In addition, we observed strong variability of LD along the chromosomes.ConclusionsOur results confirm winter and spring growth habit are the major contributors to population structure in triticale, and a family structure exists in both growth types. The specific patterns of genetic diversity observed within these types, such as the low diversity on some rye chromosomes of spring habits, provide a basis for targeted broadening of the available breeding germplasm. In addition, the genome-wide analysis of the extent and the pattern of LD will assist scientists and breeders alike in the implementation and the interpretation of association mapping in triticale.

The use of models at field and farm levels for the ex ante assessment of new pea genotypes

The use of models for genotype assessment has increased greatly in the last 10–15 years, either to assist the choice of the best cultivar for growing conditions, or to identify virtual genotypes as targets for breeding. Most studies are at the plant and field scales. However, restrictions due to work organisation at the farm level can affect genotype performance. The objective of our study was to propose a method to analyse the effects of farm constraints on crop production in the context of genotype×management×environment (G×M×E) interactions. Three types of pea genotypes, with their optimal sowing times, were compared: classic winter types sown at the end of autumn, spring sown types, and newly developed Hr types sown at the beginning of autumn. Their grain yields were simulated combining three models: a pea crop model sensitive to the main stresses affecting pea yield, a model simulating the change in soil structure according to the operations performed on the field, and a work organisation model simulating the dates of the main operations (soil tillage, sowing, harvest) at the farm scale. Simulations considering the constraints of farm work organisation showed that soil compaction was more frequent and sowing date more variable in the case of winter and spring peas than in the case of the new Hr pea genotype. This increased the risk of yield loss and the year-to-year variability of grain yield. Variety performances were thus modified taking into account farm constraints. The consideration of farm work organisation in combination with soil modelling allowed a wider variety of growing conditions to be explored than is usually the case for breeding trials on experimental stations. Generalizing the proposed method based on coupling models at farm level could thus help to define the traits favourable for innovative genotypes adapted to farmers’ conditions at no extra experimental cost.

Screening ofBrassicagermplasm for resistance toPlasmodiophora brassicaepathotypes prevalent in Canada for broadening diversity in clubroot resistance

Hasan, M. J., Strelkov, S. E., Howard, R. J. and Rahman, H. 2012. Screening of Brassica germplasm for resistance to Plasmodiophora brassicae pathotypes prevalent in Canada for broadening diversity in clubroot resistance. Can. J. Plant Sci. 92: 501–515. Clubroot disease of crucifers, caused by Plasmodiophora brassicae, poses a threat to the Canadian canola industry, and the development of resistant cultivars is urgently needed. Germplasm resistant to local pathotype(s) is the prime requirement for breeding clubroot-resistant cultivars. The objective of this study was to identify Brassica germplasm possessing resistance to P. brassicae pathotypes prevalent in Alberta. Pathotype-specific resistance was identified in the diploid species Brassica rapa (AA) and B. oleracea (CC), and in the amphidiploid B. napus (AACC). Among B. rapa genotypes, turnip was the most resistant, followed by winter type and spring type oilseed rape. The rutabaga group of B. napus, on the other hand, was homogeneous for resistance to Canadian P. brassicae pathotypes. The diploid species B. nigra (BB) also showed pathotype-specific resistance. However, the two amphidiploids carrying the B. nigra genome, B. juncea (AABB) and B. carinata (BBCC) were completely susceptible to clubroot.

Screening of Brassica germplasm for resistance to Plasmodiophora brassicae pathotypes prevalent in Canada for broadening diversity in clubroot resistance

Hasan, M. J., Strelkov, S. E., Howard, R. J. and Rahman, H. 2012. Screening ofBrassicagermplasm for resistance toPlasmodiophora brassicae pathotypes prevalent in Canada for broadening diversity in clubroot resistance. Can. J. Plant Sci. 92: 501–515. Clubroot disease of crucifers, caused by Plasmodiophora brassicae, poses a threat to the Canadian canola industry, and the development of resistant cultivars is urgently needed. Germplasm resistant to local pathotype(s) is the prime requirement for breeding clubroot-resistant cultivars. The objective of this study was to identify Brassica germplasm possessing resistance to P. brassicae pathotypes prevalent in Alberta. Pathotype-specific resistance was identified in the diploid species Brassica rapa (AA) and B. oleracea (CC), and in the amphidiploid B. napus (AACC). Among B. rapa genotypes, turnip was the most resistant, followed by winter type and spring type oilseed rape. The rutabaga group of B. napus, on the other hand, was homogeneous for resistance to Can...

Faba bean adaptation to autumn sowing under European climates

Faba bean (Vicia faba L.) is an important grain legume widely grown as a spring crop to avoid frost damage. However, there is interest in winter types for the expected benefits in grain yield as compared to spring ones. In the current experiments, we compared field performance in autumn sowings of 15 faba bean winter-type cultivars that were sown in two consecutive autumns in 12 climatically contrasting sites in Austria, France, Germany, Spain, and the UK. GGE biplot analyses (genotype plus genotype-by-environment interaction) were conducted to evaluate yield performance of faba bean genotypes and identification of mega-environments. Crossover genotype × environment was large and mainly due to the geoclimatic area. GGE biplot allowed identification of three mega-environments, namely continental, oceanic, and Mediterranean. Due to the climatic diversity of the environments, no cultivar performed well in all environments. Cultivars Clipper, Castel, Target, Wizard, and Gabl-107 performed well in oceanic mega-environment, whereas cultivars Castel, HIX, and Target performed well in continental mega-environment. None of the studied cultivars were suited to Mediterranean environments, and only Irena was able to give some modest yield at Cordoba. The average tester coordinate (defined by the average of first and second principal components of all environments) allowed to evaluate cultivars for their yielding ability and stability and to evaluate environments for their discriminating ability and to be more representative of the mega-environment. Thus, Wizard and Gabl-107 were the highest yielding cultivars being relatively stable over oceanic and continental environments. In contrast, the cultivars Irena and Divine yielded poorly at all environments. The results support the specific breeding for each major geoclimatic zone based on distinct genetic bases and selection environments.