Utilization of morphological and AFLP molecular markers in the identification of native and cultivated germplasm of Elymus scabrifolius (Poaceae)

Elymus scabrifolius es una gramínea perenne nativa de Sudamérica con gran potencial como recurso forrajero para ambientes con limitantes edáficas. En el presente trabajo se analizó la utilización de caracteres morfológicos y marcadores moleculares AFLP para la identificación genotípica de seis accesiones, un cultivar comercial y siete híbridos artificiales de esta especie. Ambos tipos de marcadores permitieron diferenciar a los materiales analizados en los respectivos dendrogramas, aunque las relaciones entre materiales variaron según el tipo de marcador. El Análisis de Componentes Principales permitió identificar las variables más relevantes para la diferenciación morfológica. Los híbridos se diferenciaron morfológicamente de ambos parentales, excepto un híbrido que se agrupó con su material paterno. Aunque en el análisis de los marcadores AFLP los híbridos se agruparon con uno de sus parentales, se pudo corroborar su origen híbrido mediante el registro de bandas paternas y polimórficas entre parentales. Se concluye que las metodologías empleadas para caracterizar los materiales analizados de E. scabrifolius serían de gran utilidad para el manejo eficiente de colecciones de germoplasma como así también para su utilización en programas de mejoramiento genético.Elymus scabrifolius is a South American perennial grass exhibiting great potential as a forage resource, especially for environments with edaphic limitations. In the present work we use morphological traits and AFLP molecular markers to genotypically identify six E. scabrifolius accessions, one commercial cultivar and seven artificial hybrids of this species. Both types of marker systems resulted in an accurate differentiation of the interrogated E. scabrifolius germplasm in the dendrograms. Moreover, relationships between the tested germplasm tend to vary according to the type of marker system used. Principal Component Analysis was used to identify the traits that best described the morphological variation. The morphological study revealed that almost all hybrids were different from their parents, with exception of one hybrid that was clustered with their own male parent. In the AFLP marker analysis, all the hybrids were clustered with one of their own parents. However, hybrid origin of those individuals was verified by the presence of paternal bands and polymorphic bands. In conclusion, the use of different methodologies to characterize and analyze E. scabrifolius materials has the potential to become of great benefit for the efficient management of germplasm collections and also for their utilization in breeding programs.Fil: Tomas, Pablo A.. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Cátedra de Mejoramiento Vegetal y Animal.Fil: Gottlieb, Alexandra M.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución.Fil: Schrauf, Gustavo E.. Universidad de Buenos Aires. Facultad de AgronomíaFil: Poggio, Lidia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución

Utilización de marcadores morfológicos y moleculares AFLP en la identificación de germoplasma nativo y cultivado de Elymus scabrifolius (Poaceae)

Elymus scabrifolius is a South American perennial grass exhibiting great potential as a forage resource, especially for environments with edaphic limitations. In the present work we use morphological traits and AFLP molecular markers to genotypically identify six E. scabrifolius accessions, one commercial cultivar and seven artificial hybrids of this species. Both types of marker systems resulted in an accurate differentiation of the interrogated E. scabrifolius germplasm in the dendrograms. Moreover, relationships between the tested germplasm tend to vary according to the type of marker system used. Principal Component Analysis was used to identify the traits that best described the morphological variation. The morphological study revealed that almost all hybrids were different from their parents, with exception of one hybrid that was clustered with their own male parent. In the AFLP marker analysis, all the hybrids were clustered with one of their own parents. However, hybrid origin of those individuals was verified by the presence of paternal bands and polymorphic bands. In conclusion, the use of different methodologies to characterize and analyze E. scabrifolius materials has the potential to become of great benefit for the efficient management of germplasm collections and also for their utilization in breeding programs.Elymus scabrifolius es una gramínea perenne nativa de Sudamérica con gran potencial como recurso forrajero para ambientes con limitantes edáficas. En el presente trabajo se analizó la utilización de caracteres morfológicos y marcadores moleculares AFLP para la identificación genotípica de seis accesiones, un cultivar comercial y siete híbridos artificiales de esta especie. Ambos tipos de marcadores permitieron diferenciar a los materiales analizados en los respectivos dendrogramas, aunque las relaciones entre materiales variaron según el tipo de marcador. El Análisis de Componentes Principales permitió identificar las variables más relevantes para la diferenciación morfológica. Los híbridos se diferenciaron morfológicamente de ambos parentales, excepto un híbrido que se agrupó con su material paterno. Aunque en el análisis de los marcadores AFLP los híbridos se agruparon con uno de sus parentales, se pudo corroborar su origen híbrido mediante el registro de bandas paternas y polimórficas entre parentales. Se concluye que las metodologías empleadas para caracterizar los materiales analizados de E. scabrifolius serían de gran utilidad para el manejo eficiente de colecciones de germoplasma como así también para su utilización en programas de mejoramiento genético

Use of AFLP and RAPD molecular genetic markers and cytogenetic analysis to explore relationships among taxa of the Patagonian Bromus setifolius complex

Bromus setifolius var. pictus (Hook) Skottsb., B. setifolius var. setifolius Presl. and B.setifolius var. brevifolius Ness are three native Patagonian taxa in the section Pnigma Dumort of the genus Bromus L. AFLP and RAPD analysis, in conjunction with genetic distance measurements and statistical techniques, revealed variation within this group and indicated that B. setifolius var. brevifolius was closely related to B. setifolius var. pictus, with both taxa being more distantly related to B. setifolius var. setifolius. Cytogenetic analysis confirmed the chromosomal number of B. setifolius var. pictus (2n = 70) and B. setifolius var. setifolius (2n = 28) and showed for the first time that B. setifolius var. brevifolius had 2n = 70. The combination of molecular genetic and cytogenetic evidence supported a species status for two of the three taxa and suggested hypotheses for the evolutionary origin of these complex taxa. Species status was also indicated for B. setifolius var. setifolius. Based on these findings, we suggest that B. setifolius var. pictus be referred to as B. pictus Hook var. pictus, and B. setifolius var brevifolius as B. pictus Hook var brevifolius. The correlation between AFLP diversity and variation in ecological parameters suggested that this marker system could be used to assess breeding progress and to monitor the domestication of Patagonian Bromus species for agronomic use

Emergence of Dallisgrass as Affected by Soil Water Availability

Water supply affects seed germination and seedling establishment of shallow-rooted warm-season grasses. This may explain the difficulty of incorporating Dallisgrass (Paspalum dilatatum Poir.) into humid temperate grasslands through interseeding. We studied the effects of water availability on seed germination and seedling growth under controlled conditions to determine which step of the establishment process was most affected. In a laboratory experiment, seeds were germinated at 0, -0.25, -0.5, -0.75, and -1 MPa water availability generated with solutions of polyethylene glycol. Although both maximum rate and total germination (P < 0.05) significantly decreased with increased water stress, the speed of germination was even more sensitive. In a greenhouse experiment, variations in seedling emergence and morphological characteristics were measured in relation to water availability. Pregerminated and dry seeds were sown in pots that were irrigated at 1-, 2- , 4-, or 7-day intervals. This species showed high sensitivity to water stress during germination and early emergence. High emergence was obtained from the daily irrigation treatment. In all other treatments, where watering frequency was extended, emergence was decreased. Results suggest that rapid germination and early adventitious root growth can be obtained only with reliable availability of water. These conditions, combined with the high temperatures required for breaking seed dormancy, occur infrequently, explaining the difficulty of achieving successful establishment of Dallisgrass. Water availability during seed germination and seedling emergence is a critical factor for survival of this species.  The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 2020Legacy DOIs that must be preserved: 10.2458/azu_rangelands_v58i1_schrau

Un sistema di trasporto del foraggio da insilare in zone montane

<div><p>Background</p><p><i>Paspalum dilatatum</i> Poir. (common name dallisgrass) is a native grass species of South America, with special relevance to dairy and red meat production. <i>P. dilatatum</i> exhibits higher forage quality than other C4 forage grasses and is tolerant to frost and water stress. This species is predominantly cultivated in an apomictic monoculture, with an inherent high risk that biotic and abiotic stresses could potentially devastate productivity. Therefore, advanced breeding strategies that characterise and use available genetic diversity, or assess germplasm collections effectively are required to deliver advanced cultivars for production systems. However, there are limited genomic resources available for this forage grass species.</p><p>Results</p><p>Transcriptome sequencing using second-generation sequencing platforms has been employed using pooled RNA from different tissues (stems, roots, leaves and inflorescences) at the final reproductive stage of <i>P. dilatatum</i> cultivar Primo. A total of 324,695 sequence reads were obtained, corresponding to c. 102 Mbp. The sequences were assembled, generating 20,169 contigs of a combined length of 9,336,138 nucleotides. The contigs were BLAST analysed against the fully sequenced grass species of <i>Oryza sativa</i> subsp. <i>japonica</i>, <i>Brachypodium distachyon</i>, the closely related <i>Sorghum bicolor</i> and foxtail millet (<i>Setaria italica</i>) genomes as well as against the UniRef 90 protein database allowing a comprehensive gene ontology analysis to be performed. The contigs generated from the transcript sequencing were also analysed for the presence of simple sequence repeats (SSRs). A total of 2,339 SSR motifs were identified within 1,989 contigs and corresponding primer pairs were designed. Empirical validation of a cohort of 96 SSRs was performed, with 34% being polymorphic between sexual and apomictic biotypes.</p><p>Conclusions</p><p>The development of genetic and genomic resources for <i>P. dilatatum</i> will contribute to gene discovery and expression studies. Association of gene function with agronomic traits will significantly enable molecular breeding and advance germplasm enhancement.</p></div

Frequency histograms showing the distribution of contigs compared to sequence read length (A), the distribution of the number of reads per contig (B), and distribution of singletons compared to read length (bp) (C).

<p>Frequency histograms showing the distribution of contigs compared to sequence read length (A), the distribution of the number of reads per contig (B), and distribution of singletons compared to read length (bp) (C).</p

Assignment of putative function and gene ontology (GO) annotations to <i>P. dilatatum</i> sequence contigs based on Biological process classification (A), Molecular function (B) and Cellular components (C).

<p>Assignment of putative function and gene ontology (GO) annotations to <i>P. dilatatum</i> sequence contigs based on Biological process classification (A), Molecular function (B) and Cellular components (C).</p

Sequence analysis of the generated <i>P. dilatatum</i> contigs compared to the reference grass genomes.

<p>The <i>P. dilatatum</i> contigs were compared using BLASTn with an e value threshold of 10⁻¹⁰ and significant matches were identified and totaled and presented as a Venn diagram.</p

Details of SSR molecular markers from <i>P. dilatatum</i> validated as polymorphic within the current study.

<p>Details of SSR molecular markers from <i>P. dilatatum</i> validated as polymorphic within the current study.</p