Landrace Diversity and Production Systems of Cowpea (Vigna unguiculata L. Walp.) in Southern Chad

In Chad, cowpea (Vigna unguiculata (L.) Walp.), is increasingly becoming a cash crop. The objective of this work is to assess the varietal diversity, analyze the traditional management of landraces and the production systems of cowpea in southern part of Chad. An inventory and an ethnobotanical survey was conducted through a participatory approach in 17 villages corresponding to two agro ecological zones. Thirty-four vernacular names and 45 landraces are inventoried. On average, 2 names are assigned per village. The number of landraces varies from 4 to 13 with an average of 9.00 per region and 2.70 per village. The highest diversity is observed in Mayo Kebbi. Sixteen morphotypes have been identified and their distribution varies according to the agro ecological zones. Productivity (31.10 %), taste (25.92 %) and grain size (18.34 %) are the farmer main preferred criteria. Farmers use leaves (47 %), pods (29.50 %) and seeds (14.75 %) to identify landraces. Cowpea cultivation is practiced on small areas and in intercropping system (78.60 %). Conservation of seeds (36.07 %), low fertility of the soils (27.85 %) and drought (17.77 %) were the main production constraints. Cowpea is stored mainly in traditional granaries (34.96 %) and on racks (22.93 %). For seeds treatment, farmers use mainly traditional means (32.37 %) and chemical products (6.67 %). Several cowpea-based dishes are identified. Cowpea has also therapeutic virtues. To improve cowpea production, appropriate actions must be considered against the constraints inventoried. The interesting landraces should also be used in a breeding program. Int. J. Appl. Sci. Biotechnol. Vol 9(3): 176-186.

Landrace added value and accessibility in Europe: what a collection of case studies tells us

In the actual climate change scenario, in situ conservation of plant genetic resources for food and agriculture can significantly contribute broadening the diversity of our food system as well as increasing its resilience; nevertheless, landrace cultivation has been dramatically reduced in the last decades all over Europe. One of the most effective approaches to counteract the loss of landrace diversity in situ is facilitating its use. Aims of this study were to (i) describe how in situ maintenance of landraces occurs in different agro-environmental conditions in Europe and (ii) identify the main factors influencing landrace added values and accessibility as means to increase their adoption by new farmers. To the purpose, a collection of 95 case studies of both garden and open field landraces maintained in situ was analysed. A first description was obtained by classifying the information into 18 purposely defined categories. Data on landraces added values and accessibility were further transformed into weighted variables; the derived quantitative scores were then used as dependent variables in univariate and multivariate analyses. Results showed that farmers alone are still the main actors maintaining landraces in situ across different European biogeographical regions, mainly carrying out their activity under organic or low-input conditions, often in marginal areas. Results of the multivariate analysis showed that (i) type of actor involved in the multiplication, (ii) the main use of the product and (iii) presence of promotion actions significantly affect garden landraces added value and accessibility; presence of promotion actions was the only factor affecting added value of open field entries. Evidence arising from this work can contribute to the establishment of a fruitful ground of discussion for future European policies and strategies to protect and increase landrace use.

Genome-wide association mapping reveals potential novel loci controlling stripe rust resistance in a Chinese wheat landrace diversity panel from the southern autumn-sown spring wheat zone

Background Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a serious foliar disease of wheat. Identification of novel stripe rust resistance genes and cultivation of resistant cultivars are considered to be the most effective approaches to control this disease. In this study, we evaluated the infection type (IT), disease severity (DS) and area under the disease progress curve (AUDPC) of 143 Chinese wheat landrace accessions for stripe rust resistance. Assessments were undertaken in five environments at the adult-plant stage with Pst mixture races under field conditions. In addition, IT was assessed at the seedling stage with two prevalent Pst races (CYR32 and CYR34) under a controlled greenhouse environment. Results Seventeen accessions showed stable high-level resistance to stripe rust across all environments in the field tests. Four accessions showed resistance to the Pst races CYR32 and CYR34 at the seedling stage. Combining phenotypic data from the field and greenhouse trials with 6404 markers that covered the entire genome, we detected 17 quantitative trait loci (QTL) on 11 chromosomes for IT associated with seedling resistance and 15 QTL on seven chromosomes for IT, final disease severity (FDS) or AUDPC associated with adult-plant resistance. Four stable QTL detected on four chromosomes, which explained 9.99–23.30% of the phenotypic variation, were simultaneously associated with seedling and adult-plant resistance. Integrating a linkage map of stripe rust resistance in wheat, 27 QTL overlapped with previously reported genes or QTL, whereas four and one QTL conferring seedling and adult-plant resistance, respectively, were mapped distantly from previously reported stripe rust resistance genes or QTL and thus may be novel resistance loci. Conclusions Our results provided an integrated overview of stripe rust resistance resources in a wheat landrace diversity panel from the southern autumn-sown spring wheat zone of China. The identified resistant accessions and resistance loci will be useful in the ongoing effort to develop new wheat cultivars with strong resistance to stripe rust.

Genome-wide association mapping reveals potential novel loci controlling stripe rust resistance in a Chinese wheat landrace diversity panel from the southern autumn-sown spring wheat zone

Background: Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a serious foliar disease of wheat. Identification of novel stripe rust resistance genes and cultivation of resistant cultivars are considered to be the most effective approaches to control this disease. In this study, we evaluated the infection type (IT), disease severity (DS) and area under the disease progress curve (AUDPC) of 143 Chinese wheat landrace accessions for stripe rust resistance. Assessments were undertaken in five environments at the adult-plant stage with Pst mixture races under field conditions. In addition, IT was assessed at the seedling stage with two prevalent Pst races (CYR32 and CYR34) under a controlled greenhouse environment.Results: Seventeen accessions showed stable high-level resistance to stripe rust across all environments in the field tests. Four accessions showed resistance to the Pst races CYR32 and CYR34 at the seedling stage. Combining phenotypic data from the field and greenhouse trials with 6404 markers that covered the entire genome, we detected 17 quantitative trait loci (QTL) on 11 chromosomes for IT associated with seedling resistance and 15 QTL on seven chromosomes for IT, final disease severity (FDS) or AUDPC associated with adult-plant resistance. Four stable QTL detected on four chromosomes, which explained 9.99%–23.30% of the phenotypic variation, were simultaneously associated with seedling and adult-plant resistance. Integrating a linkage map of stripe rust resistance in wheat, 27 QTL overlapped with previously reported genes or QTL, whereas four and one QTL conferring seedling and adult-plant resistance, respectively, were mapped distantly from previously reported stripe rust resistance genes or QTL and thus may be novel resistance loci.Conclusions: Our results provided an integrated overview of stripe rust resistance resources in a wheat landrace diversity panel from the southern autumn-sown spring wheat zone of China. The identified resistant accessions and resistance loci will be useful in the ongoing effort to develop new wheat cultivars with strong resistance to stripe rust.

Assessment of Four Portuguese Wheat Landrace Diversity to Cope With Global Warming

Wheat is a dietary staple consumed worldwide strongly responsible for proteins and carbohydrate population intake. However, wheat production and quality will scarcely fulfill forward demands, which are compounded by high-temperature (HT) events as heatwaves, increasingly common in Portugal. Thus, landraces assume crucial importance as potential reservoirs of useful traits for wheat breeding and may be pre-adapted to extreme environmental conditions. This work evaluates four Portuguese landrace yield and grain composition through attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, particularly protein content, and their responses to HT treatment mimicking a heatwave. Landraces showed distinct yield traits, especially plant height and first spike grain number, and a similar pattern in FTIR spectra, although revealing differences in grain components’ proportions. Comparison between spectra band intensity indicates that Ardito has the highest protein-related peaks, contrary to Magueija, which appears to be the landrace with higher lipid content. In plants submitted to 1 week of HT treatment 10 days after anthesis, the first spike grain size and weight were markedly reduced in all landraces. Additionally, it was observed that a general increase in grain protein content in the four landraces, being the increment observed in Ardito and Grécia, is statistically significant. The comparative assessment of control and HT average FTIR spectra denoted also the occurrence of alterations in grain polysaccharide composition. An integrated assessment of the evaluations performed revealed that Ardito and Magueija landraces presented diverse yield-related characteristics and distinct responses to cope with HT. In fact, the former landrace revealed considerable grain yield diminution along with an increase in grain protein proportion after HT, while the latter showed a significant increase in spikes and grain number, with grain quality detriment. These results reinforce the relevance of scrutinizing old genotype diversity seeking for useful characteristics, particularly considering HT impact on grain production and quality.

Genome-wide association mapping reveals potential novel loci controlling stripe rust resistance in a Chinese wheat landrace diversity panel from the southern autumn-sown spring wheat zone

Background: Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a serious foliar disease of wheat. Identification of novel stripe rust resistance genes and cultivation of resistant varieties are considered to be the most effective approaches to control this disease. In this study, we evaluated the infection type (IT), disease severity (DS) and area under the disease progress curve (AUDPC) of 143 Chinese wheat landrace accessions for stripe rust resistance. Assessments were undertaken in five environments at the adult-plant stage with Pst mixture races under field conditions, in addition, IT was assessed at the seedling stage with two prevalent Pst races (CYR32 and CYR34) under controlled greenhouse conditions.Results: Seventeen accessions showed stable high-level resistance to stripe rust across all environments under field tests, while four accessions showed resistance to the Pst races CYR32 and CYR34 at the seedling stage. Combining phenotypic data from the field and greenhouse trials with 6404 markers covering the whole genome, we detected 17 quantitative trait loci (QTL) on 11 chromosomes for IT associated with seedling resistance and 15 QTL on seven chromosomes for IT, final disease severity (FDS) or AUDPC associated with adult-plant resistance. Four stable QTL detected on four chromosomes, which explained 9.99%–23.30% of the phenotypic variation, were simultaneously associated with seedling and adult-plant resistance. Integrating a linkage map of stripe rust resistance in wheat, 27 QTL overlapped with previously reported genes or QTL, while four and one QTL conferring seedling and adult-plant resistance respectively were mapped distantly from previously reported stripe rust resistance genes or QTL and may be novel resistance loci.Conclusions: Our results provided an integrated view of stripe rust resistance resources in a Chinese wheat landrace diversity panel from the southern autumn-sown spring wheat zone. The identified resistant accessions and resistance loci will be useful in the ongoing effort to develop new wheat cultivars with strong resistance to stripe rust.

Göte Turesson’s research legacy to Hereditas: from the ecotype concept in plants to the analysis of landraces’ diversity in crops

Hereditas began with articles on plants since its first issue in May 1920 (six out of eight) and continued with more original articles (43% of the total of this journal) on plants (of which 72% of those in plants were on crops) until today. In December 1922, the 140-page article The Genotypical Response of the Plant Species to the Habitat by evolutionary botanist Göte Turesson (Institute of Genetics, Lund University, Åkarp, Sweden) became available. This publication shows that plant phenology has a genetic basis and may ensue from local adaptation. As a result of this research involving various plant species, Turesson elaborated further in this article his term ecotype “as an ecological sub-unit to cover the product arising as a result of the genotypical response of an ecospecies to a particular habitat.” Although plant articles included in Hereditas involved from its beginning, trait inheritance, mutants, linkage analysis, cytology or cytogenetics, and more recently gene mapping and analysis of quantitative trait loci with the aid of DNA markers, among others, since the mid-1980s several publications refer to the population biology of plant landraces, which are locally grown cultivars that evolved over time by adapting to their natural and cultural environment (i.e., agriculture), and that may become isolated from other populations of the same crop. This article provides a briefing about research on plant science in the journal with emphasis on crops, summarizes the legacy to genetics of Göte Turesson, and highlights some landrace diversity research results and their potential for plant breeding.

Genome-wide association mapping reveals potential novel loci controlling stripe rust resistance in a Chinese wheat landrace diversity panel from the southern autumn-sown spring wheat zone

Background: Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a serious foliar disease of wheat. Identification of novel stripe rust resistance genes and cultivation of resistant varieties are considered to be the most effective approaches to control this disease. In this study, we evaluated the infection type (IT), disease severity (DS) and area under the disease progress curve (AUDPC) of 143 Chinese wheat landrace accessions for stripe rust resistance. Assessments were undertaken in five environments at the adult-plant stage with Pst mixture races under field conditions, in addition, IT was assessed at the seedling stage with two prevalent Pst races (CYR32 and CYR34) under controlled greenhouse conditions. Results: Seventeen accessions showed stable high-level resistance to stripe rust across all environments under field tests, while four accessions showed resistance to the Pst races CYR32 and CYR34 at the seedling stage. Combining phenotypic data from the field and greenhouse trials with 6404 markers covering the whole genome, we detected 17 quantitative trait loci (QTL) on 11 chromosomes for IT associated with seedling resistance and 15 QTL on seven chromosomes for IT, final disease severity (FDS) or AUDPC associated with adult-plant resistance. Four stable QTL detected on four chromosomes, which explained 9.99%–23.30% of the phenotypic variation, were simultaneously associated with seedling and adult-plant resistance. Integrating a linkage map of stripe rust resistance in wheat, 27 QTL overlapped with previously reported genes or QTL, while four and one QTL conferring seedling and adult-plant resistance respectively were mapped distantly from previously reported stripe rust resistance genes or QTL and may be novel resistance loci. Conclusions: Our results provided an integrated view of stripe rust resistance resources in a Chinese wheat landrace diversity panel from the southern autumn-sown spring wheat zone. The identified resistant accessions and resistance loci will be useful in the ongoing effort to develop new wheat cultivars with strong resistance to stripe rust.

Genome-wide Association Mapping Reveals Potential Novel Loci Controlling Stripe-rust Resistance in a Chinese Wheat Landrace Diversity Panel From the Southern Autumn-sown Spring Wheat Zone

Background:Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a serious foliar disease of wheat. Identification of novel stripe-rust resistance genes and cultivation of resistant varieties are considered to be the most effective approaches to control this disease. In this study, we evaluated the infection type (IT), disease severity (DS) and area under the disease progress curve (AUDPC) of 143 Chinese wheat landrace accessions for stripe-rust resistance. Assessments were undertaken in five environments at the adult-plant stage with Pst mixture races under field conditions, in addition, IT was assessed at the seedling stage with two prevalent Pst races (CYR32 and CYR34) under controlled greenhouse conditions. Results:Seventeen accessions showed stable high-level resistance to stripe rust across all environments under field tests,while four accessions showed resistance to the Pst races CYR32 and CYR34 at the all-stage.Combining phenotypic data from the field and greenhouse trials with 6404 markers covering the whole genome, we detected 17quantitative trait locus(QTLs) on 11 chromosomes for IT associated with seedling resistance and 15 QTLs on seven chromosomes for IT, final disease severityor AUDPC associated with adult-plant resistance. Four stable QTLs detected on four chromosomes, which explained 9.99%–23.30% of the phenotypic variation, were simultaneously associated with seedling and adult-plant resistance. Integrating a linkage map of stripe-rust resistance in wheat, 29 QTLs overlapped with previously reported genes or QTLs, while two and oneQTLs conferring seedling and adult-plant resistancerespectively were mapped distantly from previously reported stripe rust resistance genes or QTLs and may be novel resistantloci. Conclusions:Our results provided an integrated view of stripe rust resistance resources in a Chinese wheat landrace diversity panel from the southern autumn-sown spring wheat zone.The identified resistant accessions and resistance loci will be useful in the ongoing effort to develop new wheat cultivars with strong resistance to stripe rust.