The utility of NBS-profiling for characterization of yellow rust resistance in an F6 durum wheat population

Seedling and adult plant (field) resistance to yellow rust in the durum wheat (Triticum turgidum ssp. durum) cross Kunduru-1149 x Cham-1 was characterized using a functionally-targeted DNA marker system, NBS-profiling. Chi-squared analysis indicated a four gene model conferring seedling yellow rust resistance against Puccinia striiformis f. sp. tritici isolate WYR85/22 (virulent on Yr2, Yr6, Yr7 and Yr9). Interval mapping located two QTL for yellow rust resistance on the long arm of chromosome 1B, while Kruskal–Wallis single marker regression identified a number of additional marker loci associated with seedling and/or adult plant, field resistance to yellow rust. These results suggested that much of the yellow rust resistance seen in the field may be due to seedling expressed resistance (R) genes. Characterization of the DNA sequence of three NBS marker loci indicated that all showed significant homology to functionally-characterized R-genes and resistance gene analogues (RGAs), with the greatest homology being NBS-LRR-type R-genes and RGAs from cereal species.

Quality selection and genetic diversity of Tunisian durum wheat varieties using SSR markers / Seleção de qualidade e diversidade genética de vari edades de trigo duro da tunísia usando marcadores SSR

Our study focuses on the molecular analysis of the genetic diversity within 15 Tunisian durum wheat varieties and the assessment of the efficiency of some available markers to select valuable genotypes for technological proprieties of semolina (i.e. parameters related to SDS-sedimentation, mixing time and breakdown resistance of mixograph, grain protein content and yellow colour). While several markers were validated, others were not informative within the genotypes used. A high level of polymorphic information content (PIC) was detected, with an average of 5.2 polymorph alleles per locus and 0.6 average. Old varieties have high protein content however; modern varieties display strong gluten strength. Our results thus open the opportunity to choose valuable parents on the base of pedigrees, technological properties and genetic distances; and lead us to select efficient markers for the Regional Indigenous Land Strategy (Rils) selection strategy

Nosso estudo enfoca a análise molecular da diversidade genética em 15 variedades de trigo duro tunisiano e a avaliação da eficiência de alguns marcadores disponíveis para selecionar genótipos valiosos para propriedades tecnológicas de semolina (ou seja, parâmetros relacionados à sedimentação sds, tempo de mistura e resistência à degradação do mixógrafo, teor de proteína dos grãos e cor amarela). Enquanto vários marcadores foram validados, outros não foram informativos dentro dos genótipos utilizados. Foi detectado um alto nível de conteúdo de informação polimórfica (pic), com uma média de 5,2 alelos polimórficos por locus e 0,6 média. Variedades antigas têm alto teor de proteína no entanto; variedades modernas exibem forte força de glúten. Nossos resultados abrem, assim, a oportunidade de escolher pais valiosos com base em pedigrees, propriedades tecnológicas e distâncias genéticas; e nos levam a selecionar marcadores eficientes para a estratégia de seleção da estratégia regional de terras indígenas (rils).

Genetic diversity in algerian durum wheat varieties (Triticum turgidum L var. durum) using microsatellite markers / Diversidade genética em variedades de trigo duro argelino (Triticum turgidum L var. durum) usando marcadores microssatélites

Characterization of germplasm by DNA-markers provides powerful tool to precise germplasm identification. This study aimed to quantify the genetic diversity and to estimate the phylogenetic relationship among genotypes in many crop species. The results of the present study realized between Nov and Dec 2016 in biotechnologie unit (ICARDA, Morocco) which aimed to characterize a subset of 14 Algerian selected durum wheat cultivars (Triticum turgidum L. var. durum), using 13 SSR (Single Sequence Repeat) indicated the presence of a total of 39 alleles. The genetic diversity at the 13 microsatellites loci varied from 0,142 for Xgwm337 to 0.735 for Xgwm213 with a mean of 0.444. Polymorphic information content (PIC) values ranged from 0.13 to 0.70 and the genetic distance among the cultivars from 0.15 to 0.77. Clustering analysis showed that the studied varieties were grouped according to their population of origin, suggesting a provenance effect in their ordination. In fact the most similar varieties were those introduced from CIMMYT-ICARDA breeding program, which may have common parents in their pedigree. Selections from local landraces were more similar to each other and dissimilar to CIMMYT-ICARDA material, showing an agro-ecological adaptation.

A caracterização de germoplasma por marcadores de DNA fornece uma ferramenta poderosa para a identificação precisa de germoplasma, quantificar a diversidade genética e estimar a relação filogenética entre genótipos em muitas espécies de culturas. Os resultados do presente estudo foram realizados entre novembro e dezembro de 2016 na unidade de biotecnologia (ICARDA, Marrocos) que objetivou caracterizar um subconjunto de 14 cultivares de trigo duro argelinos selecionados (Triticum turgidum L. var. durum), utilizando 13 SSR (Single Sequence Repeat ) indicou a presença de um total de 39 alelos. A diversidade genética nos 13 locos de microssatélites variou de 0,142 para Xgwm337 a 0,735 para Xgwm213 com uma média de 0,444. Os valores do conteúdo de informação polimórfica (PIC) variaram de 0,13 a 0,70 e a distância genética entre as cultivares de 0,15 a 0,77. A análise de agrupamento mostrou que as variedades estudadas foram agrupadas de acordo com sua população de origem, sugerindo um efeito de proveniência em sua ordenação. De fato, as variedades mais similares foram aquelas introduzidas no programa de criação CIMMYT-ICARDA, que podem ter pais comuns em seu pedigree. Seleções de variedades locais foram mais similares entre si e diferentes do material CIMMYT-ICARDA, mostrando uma adaptação agroecológica.

Medición del índice glucémico de 2 variedades de pastas y 2 variedades de arroz / Glycemic index of two varieties of pasta and two varieties of rice

El IG ha sido ampliamente estudiado como un indicador de los efectos fisiológicos de una comida con carbohidratos y es de interés en el manejo y la prevención de la diabetes, las dislipemias y la obesidad. Para medir el índice glucémico (IG) de dos importantes alimentos fuente de carbohidratos se realizó un ensayo con voluntarios siguiendo la metodología recomendada por la Organización Mundial de la Salud (OMS), consistente en realizar mediciones de glucemia capilar al comenzar y a los 15, 30, 45, 60, 90 y 120 minutos de ingerir el alimento en un panel de 9 individuos y calcular el área incremental bajo la curva respecto del mismo ensayo con el alimento control en este caso solución de glucosa al 20% . Se obtuvieron los siguientes resultados: Pasta de sémola de trigo candeal (Triticum durum): 38; Pasta de harina de trigo común (Triticum aestivum): 73; Arroz parboil: 59 y Arroz blanco grano largo: 71. Este ensayo confirma el bajo índice glucémico de las pastas de harina de trigo candeal, es la primera medición para una pasta de harina de trigo común adecuadamente caracterizada y señala los valores de las presentaciones predominantes de arroz en numerosos países, añadiendo una referencia para profesionales y autoridades.

The IG has been extensively studied as an indicator of the physiological effects of a carbohydrate meal with applications in the management and prevention of diabetes, dyslipidemia and obesity. A standard assay was performed to measure the glycemic index ( GI) of two significant sources of carbohydrates following the World Health Organization (WHO) recommended methodology, determining the incremental area under the blood glucose response curve of a 50g carbohydrate portion of the test food compared to the same amount of carbohydrate from a glucose solution by the same subject measured in capillary whole blood before and 15, 30, 45, 60, 90 and 120 minutes after ingestion in a total of 9 subjects. The following results were obtained: Parboil rice: 73, Long Grain White Rice: 59; Pasta of durum wheat (Triticum durum): 71, Pasta of regular flour (Triticum aestivium): 38. This test confirms the low glycemic index of pasta made from durum wheat, and is the first measurement for pasta of common wheat flour properly characterized. It also indicates the values of the prevailing presentations of rice in the region, adding a reference for professionals and authorities.

SSR- Based Genetic Diversity Assessment in Tetraploid and Hexaploid Wheat Populations.

Molecular analysis for a set of hexaploid (Triticum aestvium) and tetraploid (Triticum durum) wheat cultivars was investigated by applying 11 SSR primers set. The plant materials consisted of 45 genotypes 15 of which were Triticum aestivum and 30 of T. durum obtained from four different regions Egypt, Greece, Cyprus and Italy. PCR products were separated on a 6% denaturing polyacrylamide gel electrophoresis and produced a total of 3840 DNA fragments which were used for the molecular analysis. The estimated parameters computed by POPGENE (Version 1.32) within the two population indicated that the Nei’s genetic diversity (H) was 0.2827, and the Shannon's Information index (I) was 0.4533 with standard deviation ± 0.0699 and ± 0.0852 respectively. The analysis of population structure revealed that genetic diversity within populations (Hs=0.2761) represented 97.7% of the total genetic diversity (HT=0.2827). The proportion of the total genetic diversity that was attributed to the population differentiation was low (Gst=0.0233) within population. ANOSIM (ANalysis Of Similarities), results showed that R was equal to 0.9048 (P<0.0001) indicated that all the most similar samples of genotypes are within the same population. The wheat varieties from the four distinct regions were clustered according to SSR data into two main clusters, durum wheat varieties and bread wheat varieties, the principal coordinate analysis (PCOORDA) validated the results of the dendrogram. This study showed that the two populations still had moderate considerable level of genetic diversity and show little genetic differentiation among them. Understanding genetic variation within and between populations is essential for the establishment of an effective breeding program concerning the intraspecific and interspecific hybridization.

Genetic variation and interrelationships of agronomic characteristics in durum wheat under two constructing water regimes

This work aimed to study the grain yield components and plant characteristics related to grain yield. Twenty-four durum wheat genotypes from the ICARDA durum wheat breeding program were grown during 2006-2007 under rainfed and irrigated conditions using a complete randomized block design with three replicate in west of Iran. Correlation and path analysis were carried out. Results showed that there was strong positive association of grain yield with the number of seed/spike, biomass and harvest index. Grain yield was negatively associated with spike length and plant height in different moisture conditions. Comparatively, high genetic variation was found in grain yield and other characteristics. Hierarchical cluster analysis was used as a tool to classify the genotypes according to their grain yield ability under optimum and drought stress conditions. Among the genotypes, one of three groups of genotypes were characterized by high grain yield in optimum and drought stress conditions. These genotypes could be used as source of germplasm for breeding for drought tolerance.