Unveiling oxygen vacancy impact on lizardite thermo and mechanical properties

Here, we performed a systematic DFT study assisted by the workflow framework SimStack for the mechanical and thermodynamic properties of the clay mineral lizardite in pristine and six different types of O vacancies configurations. In most cases, the defect caused a structural phase transition in the lizardite from the trigonal (pristine) to the triclinic phase. The results show that oxygen vacancies in lizardite significantly reduce the lattice thermal conductivity, accompanied by an elastic moduli reduction and an anisotropy index increase. Through the P–V relation, an increase in compressibility was evidenced for vacancy configurations. Except for the vacancy with the same crystalline structure as pristine lizardite, the sound velocities of the other vacancy configurations produce a decrease in these velocities, and it is essential to highlight high values for the Grüneisen parameter. We emphasize the great relevance of the punctual-defects introduction, such as O vacancies, in lizardite, since this microstructural design is responsible for the decrease of the lattice thermal conductivity in comparison with the pristine system by decreasing the heat transfer ability, turning lizardite into a promising candidate for thermoelectric materials

Efficiency of indirect selection for green biomass production of Urochloa ruziziensis.

We aimed to measure the efficiency of visual selection of plant vigor for green biomass production of U. ruziziensis using single- and multitrait approaches to maximize the predictive accuracy of the genetic value. The green biomass production and plant vigor of 254 U. ruziziensis clones were measured over nine evaluation cuttings to determine the efficiency of these approaches for production improvement. Individual and multicutting analyses were performed under single-trait and multitrait approaches using mixed models. The efficiency of visual selection was assessed by measuring plant vigor based on direct and indirect genetic gains. Plant vigor showed a high genetic association with green biomass and could be selected for production, especially in the initial phases of breeding programs. The multitrait approach was superior to the single-trait approach in predicting the genetic value of the clones, and it can be used in U. ruziziensis breeding programs

Reação de genótipos de feijão-caupi a Macrophomina phaseolina [(Tassi) Goid.], agente causal da podridão cinzenta do caule.

O objetivo deste trabalho foi avaliar a existência de variabilidade genética em genótipos de feijão-caupi, inoculados artificialmente com M. phaseolina, visando à obtenção de fontes de resistência à podridão cinzenta do caule, e disponibilizar ao Programa de Melhoramento do Feijão-Caupi genitores que possam ser usados no melhoramento genético, visando à resistência genética ao fungo. Vale destacar que os resultados obtidos neste trabalho estão alinhados aos Objetivos de Desenvolvimento Sustentáveis (ODS) 2 (Fome Zero), especialmente às metas de acesso a alimentos seguros e nutritivos, às relacionadas a garantir sistemas sustentáveis de produção de alimentos e àquelas alinhadas em manter a diversidade genética de sementes

Controle de Sclerotium rolfsii Sacc com óleo essencial de Aloysia lycioides Cham.

O feijão-caupi (Vigna unguiculata (L.) Walp) é considerado uma das fontes alimentares mais importantes e estratégicas para as regiões tropicais e subtropicais do planeta, em cujo cultivo ocorre significativa geração de emprego e renda. Entretanto, a cultura tem apresentado produtividade de grãos aquém do esperado. Um dos fatores é a murcha-de-esclerócio causada pelo fungo Sclerotium rolfsii Sacc

Visual selection of Urochloa ruziziensis genotypes for green biomass yield.

The breeding program of Urochloa ruziziensis evaluates many genotypes in initial phases. Evaluations through grades might make the selection less costly. The aim of this study was to verify the efficiency of visual selection for green biomass yield in relation to different selection strategies, such as mass selection by phenotypic mean, BLUP (Best Linear Unbiased Prediction) and at random. For this purpose, 2,309 regular genotypes were evaluated in an augmented block design in two cuts. The evaluators gave grades for plant vigor, and later, the plots were measured for green biomass yield. The coincidences of the selected genotypes were estimated by different selection strategies. Then, 254 clones of the genotypes selected in different strategies were evaluated in a clonal test in a triple lattice design in four cuts. The statistical analyses were performed in SAS using the Mixed procedure. The regular genotype level and clone-mean basis heritabilities were 31.16 and 62.91%, respectively, for green mass yield. The expected selection gains were 21.09% (visual), 25.43% (phenotypic mean), and 27.5% (BLUP). Moreover, the realized heritabilities for these strategies were 15.58, 11.87, and 15.86%, respectively, which might be associated with genotype by environment interaction. Therefore, the visual selection could be a useful strategy in initial phases of a U. ruziziensis breeding program because the efficiency was moderate to high in relation to phenotypic mean and BLUP