Produção de milho em razão da aplicação de fertilizantes organominerais e minerais.

Projeto/Plano de Ação: 01.09.10.103-04

Efeito de sistemas de cultivo sobre a porosidade e retenção de água em um solo Laterítico Bruno-Avermelhado distrófico (Paleudult)

The effect of tillage systems on soil-air-water relationships was studied through the determination of some physical properties in a Lateritic Reddish-Brown Dystrophic soil (Paleudult), which received for five years the following treatments: 1) native pasture; 2) rotation clover-wheat/ soybeans in conventional tillage; 3) wheat/soybeans in no-tillage; 4) wheat/soybeans in conventional tillage; 5) wheat/maize in conventional tillage; 6) wheat/soybeans in minimum tillage; 7) wheat/maize in no-tillage. The results did not show marked and lasting effects of tillage systems on the pore size distribution and soil water retention, thus giving indication that physical deterioration of this soil is basically concerned with water erosion.Com o objetivo de avaliar o efeito de sistemas de cultivo sobre as relações solo-ar-água, foram feitas determinações de algumas propriedades físicas em um solo Laterítico Bruno-Avermelhado Distrófico (Paleudult) submetido durante cinco anos aos seguintes tratamentos: 1) pastagem nativa; 2) rotação trevo-trigo-soja em preparo convencional; 3) trigo/soja em plantio direto; 4) trigo/soja em preparo convencional; 5) trigo/milho em preparo convencional; 6) trigo/soja em cultivo mínimo; 7) trigo/milho em plantio direto. Os resultados obtidos não permitiram detectar efeitos sensíveis e duradouros dos sistemas de cultivo sobre a distribuição do tamanho de poros e a retenção de água, indicando que a degradação física desse solo se dá basicamente pela erosão hídrica

Genetic Diversity within a Collection of Italian Maize Inbred Lines: A Resource for Maize Genomics and Breeding

Genetic diversity is fundamental for studying the complex architecture of the traits of agronomic importance, controlled by major and minor loci. Moreover, well-characterized germplasm collections are essential tools for dissecting and analyzing genetic and phenotypic diversity in crops. A panel of 360 entries, a subset of a larger collection maintained within the GenBank at CREA Bergamo, which includes the inbreds derived from traditional Italian maize open-pollinated (OP) varieties and advanced breeding ones (Elite Inbreds), was analyzed to identify SNP markers using the tGBS® genotyping-by-sequencing technology. A total of 797,368 SNPs were found during the initial analysis. Imputation and filtering processes were carried out based on the percentage of missing data, redundant markers, and rarest allele frequencies, resulting in a final dataset of 15,872 SNP markers for which a physical map position was identified. Using this dataset, the inbred panel was characterized for linkage disequilibrium (LD), genetic diversity, population structure, and genetic relationships. LD decay at a genome-wide level indicates that the collection is a suitable resource for association mapping. Population structure analyses, which were carried out with different clustering methods, showed stable grouping statistics for four groups, broadly corresponding to ‘Insubria’, ‘Microsperma’, and ‘Scagliolino’ genotypes, with a fourth group composed prevalently of elite accessions derived from Italian and US breeding programs. Based on these results, the CREA Italian maize collection, genetically characterized in this study, can be considered an important tool for the mapping and characterization of useful traits and associated loci/alleles, to be used in maize breeding programs