Efficiency of marker-assisted selection in detection of ascochyta blight resistance in Tunisian chickpea breeding lines

Ascochyta blight (AB) resistance reactions were studied in 23 chickpea cultivars, mainly advanced lines and Tunisian varieties from the Tunisian chickpea breeding program, growing both at two locations and under controlled conditions. Two co-dominant markers both associated with AB resistance were also used in this study; the CaETR marker tightly linked to QTLAR1 in combination with the SCAR SCY17590 marker linked to QTLAR2 to explore their usefulness in discriminating between resistant and susceptible chickpea genotypes. These two markers contribute efficiently in the selection of new chickpea varieties with better combinations of alleles to ensure durable resistance to AB. The advanced line V10 presenting the resistance allele for CaETR, but being still heterozygous for the SCAR17590 was characterized as resistant to moderately resistant in field studies and under controlled conditions. This line could be very useful for developing a new variety that is fixed for both resistance alleles and expresses good levels of resistance to AB in different chickpea cropping environments. These markers are very useful in assisting chickpea breeding programs, especially thanks to their robustness, their co-dominance and their utility across different genetic backgrounds

Molecular characterization and genetic diversity of Prunus rootstocks

The definitive version is available at: http://www.sciencedirect.com/science/journal/03044238Twenty microsatellite primer pairs, previously developed in peach, were used to characterize and to explore genetic relationships among 44 clones, representing three groups of rootstocks defined as: (1) Peach-based rootstocks (Prunus dulcis x P. persica, P. persica x P. davidiana); (2) Myrobalan - Marianna plums (P. cerasifera, and interspecific hybrids having P. cerasifera as a parent); and (3) Slow growing plums (P. insititia, P. domestica, and P. domestica x P. spinosa). Eighteen SSR markers, from the 20 initially used, were able to amplify polymorphic products for the Peach-based rootstocks and 13 common markers gave also polymorphism for the Myrobalan-Marianna and Slow growing plums groups. The Dice coefficient of similarity was calculated between all pairs of accessions and their genetic similarity represented by a principal coordinate analysis. The genetic diversity detected among the 44 clones studied divided them in three groups, which are in agreement with their current taxonomic classification and their morphological characteristics. A set of three microsatellites (BPPCT001, CPPCT022 and UDP98-407) can distinguish between all the clones analyzed. The analysis within groups reveal another two sets of three SSR to distinguish between the clones from the peach based rootstocks and the myrobalan-Marianna plums respectively and only a single SSR is needed to distinguish within the clones from the Slow growing plums group. These results demonstrate the high potential of the SSR analysis for peach rootstock identification and studies of diversity in Prunus species.This research was funded by CICYT (Comisión Interministerial de Ciencia y Tecnología AGL 2005-05533), INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, RF03-014-C2 and RF2007-00026-C02-01), DGA (Diputación General de Aragón, A44). M. Bouhadida was supported by a fellowship from the AECI (Agencia Española de Cooperación Internacional) of the Spanish Ministry of Foreign Affairs and an I3P-PC2006 contract from the CSIC-FSE for M.J. Gonzalo.Peer reviewe

Análisis de la diversidad genética en melocotonero [P. persica (L.) Batsch] y en patrones del género Prunus

183 Pag.[ES] En este trabajo, se han caracterizado 30 cultivares de melocotonero procedentes de un mismo área de cultivo en Aragón (19 de los 30 cultivares son supuestos clones de una misma variedad: ‘Miraflores’), utilizando 20 marcadores microsatélites (SSRs) desarrollados en melocotonero. Todos los marcadores amplificaron un valor medio de 2,3 alelos por locus, y permitieron la identificación de 16 genotipos de los 30 estudiados, mientras que 14 clones de ‘Miraflores’ mostraron el mismo perfil genético para todos los loci. Por otra parte, se ha caracterizado un conjunto de 94 cultivares de melocotonero pertenecientes al banco de germoplasma español, de referencia nacional de melocotonero, que incluye 64 cultivares locales españoles y 30 cultivares procedentes de programas de mejora internacionales. Se eligieron 15 marcadores SSRs, seleccionados por su alto nivel de polimorfismo en melocotonero. Se obtuvo un valor medio de 6,7 alelos por locus con todos los marcadores, mostrando así una alta diversidad genética entre los 94 cultivares estudiados. Se ha observado una mayor distancia genética entre los melocotones de carne dura y los melocotones de carne blanda, y principalmente entre los melocotones españoles de carne dura y el resto de los cultivares. Con sólo 8 de los 15 SSRs utilizados en este trabajo, se pueden distinguir correctamente todos los cultivares estudiados. En este estudio, se han caracterizado mediante los marcadores SSRs y la PCR-RFLP, especies y patrones (híbridos ínterespecíficos) de Prunus, basándose en el análisis del ADN nuclear y cloroplástico, respectivamente.[EN] In this study, we characterised 30 peach cultivars originated from a local area in Aragón (Spain) (19 are described as clones of the ‘Miraflores’ peach variety) using 20 SSR primer pairs developed in peach. All markers amplified an average of 2.3 alleles per locus, and identified 16 genotypes from the 30 studied, while 14 (clones of ‘Miraflores) showed the same genetic profile. Moreover, we characterised a sample of 94 peach cultivars from the national collection composed of 64 local Spanish peach and 30 cultivars from modern breeding programs. For this aim, we used a set of 15 microsatellite markers selected for their high polymorphism from published sequences. An average of 6.7 alleles per locus was amplified with all SSRs, expressing a high genetic diversity within the 94 cultivars studied. High genetic distances were observed when comparing non-melting peach cultivars with melting ones, and especially between Spanish non-melting peaches and the rest of cultivars. Only eight SSRs from the 15 used in this study, were able to distinguish unambiguously all the cultivars studied. In this study, a characterisation of Prunus species and rootstocks (interspecific hybrids) was also carried out, on the basis of nuclear and chloroplast DNA analyses using SSRs and the PCR-RFLP, respectively. A set of 20 SSRs was used to characterize 44 Prunus rootstocks belonging to three groups: Peach-based rootstocks; Myrobalan-Marianna plums; and Slow growing plums. SSRs in this case showed a high level of polymorphism and amplified an average of 16 alleles per locus, allowing the total identification of all rootstocks.Peer reviewe

Evaluation of the Antagonistic Effect of <i>Pseudomonas</i> Rhizobacteria on Fusarium Wilt of Chickpea

This study aimed to isolate rhizobacteria belonging to the genus Pseudomonas with plant-growth-promoting properties that can be used in the control of chickpea wilt disease caused by Fusarium oxysporum f. sp. ciceris (Foc). The production of antifungal compounds by the isolated rhizobacteria was assessed against two Foc isolates, coded Foc-S1 and Foc-S2. Strains E1FP13, E1FP4, and E1PP7 were the most effective against Foc-S1, with percentages of 52.77%, 48.37%, and 47.97%, respectively, while E1PP6, E1FP13, and E1PP15 were the most effective against Foc-S2 with percentages of 52.20%, 52.09%, and 45.38%, respectively. All five isolates were identified as Pseudomonas species using 16S rRNA sequencing. The microscopic examination of the impact of the Pseudomonas strains on Foc revealed that all five strains caused morphological changes in Foc, such as granulation and condensation of the cytoplasm, fragmentation, and deformation of the hyphae. The strains produced several plant-growth-promoting compounds, such as cellulase, hydrogen cyanide, indole acetic acid, ammonia, siderophores, lipase, protease, and solubilized phosphate. They were also able to significantly increase chickpea growth and reduce wilt disease, with E1FP13 resulting in the highest disease reductions of 55.77% (Foc-S1) and 53.33% (Foc-S2). The results revealed that our isolates can make promising biocontrol agents for controlling chickpea wilt disease

Molecular characterization of Miraflores peach variety and relatives using SSRs

The definitive version is published in: http://www.sciencedirect.com/science/journal/03044238Some traditional peach varieties, originated from the region of Aragón (Spain), were analysed by SSRs (Simple Sequence Repeats). The aim of this research was to characterize 19 clones related to ‘Miraflores’ variety, with unknown pedigrees, to assess their genetic diversity and to elucidate their possible relationships with 10 traditional peach varieties. Twenty SSR primer pairs with high levels of polymorphism, which have been previously developed for peach, were used in this study. A total of 46 alleles were obtained for all the microsatellites studied, ranging from one to six alleles per locus, with a mean value of 2.3 alleles per locus. Fourteen SSRs were polymorphic in the set of varieties studied and permitted to distinguish 16 different genotypes out of the 30 initially studied, although fourteen ‘Miraflores’ clones showed identical gel profiles. The genetic distance matrix was used to construct Neighbor joining cluster and to perform principal coordinate analysis which allowed the arrangement of all the genotypes according to their genetic relationships. The genetic relationships among these traditional peach varieties, and in particular among ‘Miraflores’ clones are discussed. The obtained results confirm that microsatellite markers are very useful for these purposes.We are thankful to T.N. Zhebentyayeva and G.L. Reighard for helpful comments on the manuscript. This research was funded by CICYT (Comisión Interministerial de Ciencia y Tecnología, AGL2002-04219 and AGL 2005-05533), INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentación, RF03-014-C2), Bilateral Spain-France (HF03-273) and DGA (A28, A44) projects and co-funded by the European Regional Development Fund. M. Bouhadida was supported by a fellowship from the AECI (Agencia Española de Cooperación Internacional) of the Spanish Ministry of Foreign Affairs.Peer reviewe

Efficiency of marker-assisted selection in detection of ascochyta blight resistance in Tunisian chickpea breeding lines

Ascochyta blight (AB) resistance reactions were studied in 23 chickpea cultivars, mainly advanced lines and Tunisian varieties from the Tunisian chickpea breeding program, growing both at two locations and under controlled conditions. Two co-dominant markers both associated with AB resistance were also used in this study; the CaETR marker tightly linkedto QTLAR1 in combination with the SCAR SCY17590 marker linked to QTLAR2 to explore their usefulness in discriminating between resistant and susceptible chickpea genotypes. These two markers contribute efficiently in the selection of new chickpea varieties with better combinations of alleles to ensure durable resistance to AB. The advanced line V10 presentingthe resistance allele for CaETR, but being still heterozygous for the SCAR17590 was characterized as resistant to moderately resistant in field studies and under controlled conditions. This line could be very useful for developing a new variety that is fixed for both resistance alleles and expresses good levels of resistance to AB in different chickpea cropping environments. These markers are very useful in assisting chickpea breeding programs, especially thanks to their robustness, their co-dominance and their utility across different genetic backgrounds. © Firenze University Press.This research was funded by MESRT (Ministère de l’Enseignement Supérieur et de la Recherche Scientifique- Tunisie) and Co-funded by the bilateral Spain Tunisian project (AECI: Agencia Española de Cooperación Internacional).Peer Reviewe

Efficiency of marker-assisted selection in detection of ascochyta blight resistance in Tunisian chickpea breeding lines

Ascochyta blight (AB) resistance reactions were studied in 23 chickpea cultivars, mainly advanced lines and Tunisian varieties from the Tunisian chickpea breeding program, growing both at two locations and under controlled conditions. Two co-dominant markers both associated with AB resistance were also used in this study; the CaETR marker tightly linked to QT_LAR1 in combination with the SCAR SCY17₅₉₀ marker linked to QTL_AR2 to explore their usefulness in discriminating between resistant and susceptible chickpea genotypes. These two markers contribute efficiently in the selection of new chickpea varieties with better combinations of alleles to ensure durable resistance to AB. The advanced line V10 presenting the resistance allele for CaETR, but being still heterozygous for the SCAR17₅₉₀ was characterized as resistant to moderately resistant in field studies and under controlled conditions. This line could be very useful for developing a new variety that is fixed for both resistance alleles and expresses good levels of resistance to AB in different chickpea cropping environments. These markers are very useful in assisting chickpea breeding programs, especially thanks to their robustness, their co-dominance and their utility across different genetic backgrounds

Efficiency of marker-assisted selection in detection of ascochyta blight resistance in Tunisian chickpea breeding lines

Ascochyta blight (AB) resistance reactions were studied in 23 chickpea cultivars, mainly advanced lines and Tunisian varieties from the Tunisian chickpea breeding program, growing both at two locations and under controlled conditions. Two co-dominant markers both associated with AB resistance were also used in this study; the CaETR marker tightly linkedto QTLAR1 in combination with the SCAR SCY17590 marker linked to QTLAR2 to explore their usefulness in discriminating between resistant and susceptible chickpea genotypes. These two markers contribute efficiently in the selection of new chickpea varieties with better combinations of alleles to ensure durable resistance to AB. The advanced line V10 presentingthe resistance allele for CaETR, but being still heterozygous for the SCAR17590 was characterized as resistant to moderately resistant in field studies and under controlled conditions. This line could be very useful for developing a new variety that is fixed for both resistance alleles and expresses good levels of resistance to AB in different chickpea cropping environments. These markers are very useful in assisting chickpea breeding programs, especially thanks to their robustness, their co-dominance and their utility across different genetic backgrounds. © Firenze University Press.This research was funded by MESRT (Ministère de l’Enseignement Supérieur et de la Recherche Scientifique- Tunisie) and Co-funded by the bilateral Spain Tunisian project (AECI: Agencia Española de Cooperación Internacional).Peer Reviewe

Fusarium Wilt Affecting Chickpea Crop

Chickpea (Cicer arietinum L.) contributes 18% of the global production of grain legume and serves as an important source of dietary protein. An important decrease in cropping area and production has been recorded during the last two decades. Several biotic and abiotic constraints underlie this decrease. Despite the efforts deployed in breeding and selection of several chickpea varieties with high yield potential that are tolerant to diseases, the situation has remained the same for the last decade. Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris (Foc) is the major soilborne fungus affecting chickpeas globally. Fusarium wilt epidemics can devastate crops and cause up to 100% loss in highly infested fields and under favorable conditions. To date, eight pathogenic races of Foc (races 0, 1A, 1B/C, 2, 3, 4, 5 and 6) have been reported worldwide. The development of resistant cultivars is the most effective method to manage this disease and to contribute to stabilizing chickpea yields. Development of resistant varieties to fusarium wilt in different breeding programs is mainly based on conventional selection. This method is time‐consuming and depends on inoculum load and specific environmental factors that influence disease development. The use of molecular tools offers great potential for chickpea improvement, specifically by identifying molecular markers closely linked to genes/QTLs controlling fusarium wilt

Genetic variability of introduced and local Spanish peach cultivars determined by SSR markers

38 Pag., 5 Tabl., 4 Fig. The definitive version is available at: at www.springerlink.comA set of 94 peach cultivars including Spanish native peach and foreign commercial cultivars were analyzed using 15 SSR markers, selected for their high level of polymorphism. The number of alleles obtained varied from two to 11 with an average of 6.73 giving 185 different genotypes. All the cultivars showed a unique genetic profile, each one using different genotypic combination of all loci. BPPCT001 was the most informative locus showing also the highest discrimination power. Only six loci allowed the unambiguous separation of all the Spanish native cultivars studied, and the genotypic combination of only eight loci permitted the total differentiation of the 94 peach cultivars analyzed. The six selected loci (BPPCT001, BPPCT006, BPPCT008, PS9f8, UDP98-022, and UDP98-412) seem to be very useful for future Spanish peach identification works, and they will help to establish a molecular data base for native peach cultivars. UPGMA analysis was performed from the genetic distance matrix, and allowed the arrangement of all genotypes according to their genetic diversity. The genetic diversity among cultivars, observed in this work, led to their separation according to their regional origin, their morphological characteristics, and especially according to their fruit traits. Analysis of molecular variance was performed for seven populations from different regions of Spain and USA to examine the distribution of genetic variation of the studied accessions, showing that the major variation occurred within populations in each geographic site. The results reveal the existence of two diversity regions in Spain for peach germplasm.This study was supported by the Spanish MICINN (Ministry of Science and Innovation) projects AGL2005-05533 and AGL-2008-00283, cofunded by FEDER, INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, project RF2007-00026-C02-00) and the Regional Government of Aragon (A44). M. Bouhadida was supported by a fellowship from the AECI (Agencia Española de Cooperación Internacional) of the Spanish Ministry of Foreign Affairs, and M.J. Gonzalo was the beneficiary of an I3P-PC2006 contract from the CSIC-FSE.Peer reviewe