Papers by Leonardo Ormoli
Scientific Reports, 2015
in agricoltura e l'analisi dell'economia agraria -Unita `di ricerca per la selezione dei cereali ... more in agricoltura e l'analisi dell'economia agraria -Unita `di ricerca per la selezione dei cereali e la valorizzazione delle varieta `vegetali (CRA-SCV) via R. Forlani 3, 26866 Sant'Angelo Lodigiano (LO) -Italy, 2 Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria -Unita `di ricerca per l'ingegneria agraria (CRA-ING) via della Pascolare, 16, 00015 Monterotondo Scalo (RM) -Italy. A collection of 157 Triticum aestivum accessions, representative of wheat breeding in Italy during the 20 th century, was assembled to describe the evolutionary trends of cultivated varieties throughout this period. The lines were cultivated in Italy, in two locations, over two growing seasons, and evaluated for several agronomical, morphological and qualitative traits. Analyses were conducted using the most common univariate approach on individual plant traits coupled with a correspondance multivariate approach. ANOVA showed a clear trend from old to new varieties, leading towards earliness, plant height reduction and denser spikes with smaller seeds. The average protein content gradually decreased over time; however this trend did not affect bread-making quality, because it was counterbalanced by a gradual increase of SDS sedimentation volume, achieved by the incorporation of favourable alleles into recent cultivars. Correspondence analysis allowed an overall view of the breeding activity. A clear-cut separation was observed between ancient lines and all the others, matched with a two-step gradient, the first, corresponding roughly to the period 1920-1940, which can be ascribed mostly to genetics, the second, from the 40s onward, which can be ascribed also to the farming practice innovations, such as improvement of mechanical devices and optimised use of fertilizers. ermplasm collections represent valuable genetic resources for breeding programmes aimed at delivering new superior cultivars that are better suited to the technological and nutritional needs of the market. Traditionally, germplasm collections are screened for phenotypic traits and the lines presenting the desired phenotype are then crossed with an elite cultivar, to incorporate the desired trait into the elite genetic background. In contrast to such a ''top-down'' approach, an alternative ''bottom-up'' strategy was recently developed, which starts with the analysis at the genomic sequence level, and then works backwards up to the phenotype by means of linkage disequilibrium through genome wide association scan (GWAS) 1 . When this type of analysis is performed across a highly diverse set of accessions, which contain many more historical recombination events compared to the bi-parental populations commonly used in linkage analysis, a much higher mapping resolution is achieved. Recently, GWAS has been carried out successfully in wheat for the identification of Quantitative Trait Loci (QTLs) linked to yield and agronomic traits 2-4 and resistance to pathogens . The huge size of many germplasm collections, however, often hinders their exploitation; hence, the need to focus on core collections, i.e. representative manageable samples better suited to perform the initial assessments, before reexploring broader ranging materials 8 . Given all the previous assumptions, within the Triticum aestivum collection available at CRA-SCV, including more than 4000 accessions, a sub-collection was identified and a GWAS project was started to identify possible linkages between molecular markers and relevant breeding traits. The accessions, selected following a temporal principle (year of constitution or diffusion) integrated with agronomic and qualitative information, summarize the process of wheat breeding in Italy during the last hundred years. Historical series of genotypes have been used in different countries to assess the genetic gains achieved after the onset of modern wheat breeding . The prevailing factor in all the environments was the breeding success in increasing grain yield potential, largely attributed to changes in biomass partitioning, i. e. harvest index. The increase of harvest index was in turn the consequence of the decrease of plant height and of higher grain number per square meters of modern cultivars, while changes in total biomass production and grain weight did not show a
Association mapping, a high-resolution method for mapping quantitative trait loci based on linkag... more Association mapping, a high-resolution method for mapping quantitative trait loci based on linkage disequilibrium, holds great promise for the dissection of complex genetic traits, like most of those of agricultural importance. A genome-wide association study (GWAS) is in progress on a Triticum aestivum germplasm collection consisting of 184 lines (landraces, old and modern varieties), summarizing the process of wheat breeding in Italy during the last hundred years. The collection has been genotyped with the Infinium iSelectHD 90K (Illumina). SNP data were filtered using the R-Studio software (http://www.rstudio.com/). Genotypes with more than 10% of missing data, monomorphic and rare SNPs (Minor allele frequency < 1%) as well as markers with more than 5% of missing data were not considered for the population structure analyses performed on PAST (PAlaeontological STatistics) software (http://folk.uio.no/ohammer/past/). Out of 81,587 available SNPs, 23,329 were used for phylogenet...
Association mapping, a high-resolution method for mapping quantitative trait loci based on linkag... more Association mapping, a high-resolution method for mapping quantitative trait loci based on linkage disequilibrium, holds great promise for the dissection of complex genetic traits, like most of those of agricultural importance. A genome-wide association study (GWAS) is in progress on a Triticum aestivum germplasm collection consisting of 184 lines (landraces, old and modern varieties), summarizing the process of wheat breeding in Italy during the last hundred years. The collection has been genotyped with the Infinium iSelectHD 90K (Illumina). SNP data were filtered using the R-Studio software (http://www.rstudio.com/). Genotypes with more than 10% of missing data, monomorphic and rare SNPs (Minor allele frequency < 1%) as well as markers with more than 5% of missing data were not considered for the population structure analyses performed on PAST (PAlaeontological STatistics) software (http://folk.uio.no/ohammer/past/). Out of 81,587 available SNPs, 23,329 were used for phylogenet...
Scientific Reports, 2015
1 Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria -Unità di ricerca per... more 1 Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria -Unità di ricerca per la selezione dei cereali e la valorizzazione delle varietà vegetali (CRA-SCV) via R. Forlani 3, 26866 Sant'Angelo Lodigiano (LO) -Italy, 2 Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria -Unità di ricerca per l'ingegneria agraria (CRA-ING) via della Pascolare, 16, 00015 Monterotondo Scalo (RM) -Italy.
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Papers by Leonardo Ormoli