Mariele Müller

Bio: Mariele Müller is an academic researcher from Universidade de Passo Fundo. The author has contributed to research in topics: Heliotropism & Canopy. The author has an hindex of 4, co-authored 10 publications receiving 53 citations.

Adaptability and Stability of Yield and Industrial Grain Quality with and without Fungicide in Brazilian Oat Cultivars

Abstract: The use of productive cultivars with adaptability and stability and less demanding to fungicide use are critical to the sustainability of production factors. The objective of this work was to determine the per se performance of white oat cultivars and parameters of adaptability and stability on yield and grain quality in the proposition of cultivars more responsive in reducing the use fungicide. The study was conducted in Augusto Pestana, RS, Brazil, between the years 2010 and 2013. The experimental design was randomized blocks with six replicates, three with and three without fungicide. The study evaluated 14 white oat cultivars for yield and industrial capability. The white oat cultivars FAEM 4 Carlasul and URS Corona indicate high grain yield with stability and general adaptability, independent of chemical control. The cultivar URS Corona shows together high yield and thousand grain weight and hectoliter with general adaptability and stability in the absence of fungicide. Although no stability has been detected in industrial yield without the use of fungicides, cultivars of URS Charrua, URS Corona and URS Taura show high means with general adaptability.

Grain Yield Differences of Soybean Cultivars Due to Solar Radiation Interception

Abstract: Soybean [Glycine max (L.) Merr.] growth rate and grain yield are modified by the interception and solar radiation use efficiency. Thus, it is desirable that the most of plant photosynthetic structures intercepting solar radiation in order to have increment in carbon fixation and reflection on growth and yield. The goal of this study was to assess if soybean cultivars differ in grain yield in relation to solar radiation interception. Four soybean cultivars were evaluated at stages V6, V9, R2, R4, R6 and R8. To determine the photosynthetically active radiation interception by the canopy, the plants were divided into two parts (upper and lower strata). For grain yield components, the plants were divided into three parts (upper, middle and lower thirds). Of the photosynthetically active radiation intercepted by the vegetative canopy at the reproductive stages, the maximum observed intercept was 5.2% in the lower stratum of the plants. The number of infertile nodes increased in the lower third of plants due to low interception of solar radiation in this plant region. Thus, the soybean cultivars more efficient in intercepting photosynthetically active radiation inside the vegetative canopy showed higher grain yields.

Soybean Root Growth in Response to Chemical, Physical, and Biological Soil Variations.

Abstract: Environmental conditions affect crop yield, and water deficit has been highlighted by the negative impact on soybean grain production. Radicial growth in greater volume and depth can be an alternative to minimize losses caused by a lack of water. Therefore, knowledge of how soybean roots behave before the chemical, physical, and biological attributes of the soil can help establish managements that benefit in-depth root growth. The objective was to evaluate the growth of soybean roots in response to chemical, physical, and biological variations in the soil, in different soil locations and depths. Six experiments were conducted in different locations. Soil samples were collected every 5 cm of soil up to 60 cm of soil depth for chemical, physical, and biological analysis. The roots were collected every 5 cm deep up to 45 cm deep from the ground. The six sites presented unsatisfactory values of pH and organic matter, and presented phosphorus, potassium, and calcium at high concentrations in the first centimeters of soil depth. The total porosity of the soil was above 0.50 m3 m-3, but the proportion of the volume of macropores, micropores, and cryptopores resulted in soils with resistance to penetration to the roots. Microbial biomass was higher on the soil surface when compared to deeper soil layers, however, the metabolic quotient was higher in soil depth, showing that microorganisms in depth have low ability to incorporate carbon into microbial biomass. Root growth occurred in a greater proportion in the first centimeters of soil-depth, possibly because the soil attributes that favor the root growth is concentrated on the soil surface.

Daily heliotropic movements assist gas exchange and productive responses in DREB1A soybean plants under drought stress in the greenhouse.

Abstract: Drought stress is one of the most severe environmental constraints on plant production. Under environmental pressures, complex daily heliotropic adjustments of leaflet angles in soybean can help to reduce transpiration losses by diminishing light interception (paraheliotropism), increase diurnal carbon gain in sparse canopies and reduce carbon gain in dense canopies by solar tracking (diaheliotropism). The plant materials studied were cultivar BR 16 and its genetically engineered isoline P58, ectopically overexpressing AtDREB1A, which is involved in abiotic stress responses. We aimed to follow the movements of central and lateral leaflets in vegetative stages V7-V10 and reproductive stages R4-R5, integrating the reversible morphogenetic changes into an estimate of daily plant photosynthesis using three-dimensional modeling, and to analyze the production parameters of BR 16 and P58. The patterns of daily movements of central leaflets of BR 16 in V7-V10 and R4-R5 were similar, expressing fewer diaheliotropic movements under drought stress than under non-limiting water conditions. Daily heliotropic patterns of lateral leaflets in V7-V10 and R4-R5 showed more diaheliotropic movements in drought-stressed P58 plants than in those grown under non-limiting water conditions. Leaf area in R4-R5 was generally higher in P58 than in BR 16. Drought significantly affected gas exchange and vegetative and reproductive architectural features. DREB1A could be involved in various responses to drought stress. Compared with the parental BR 16, P58 copes with drought through better compensation between diaheliotropic and paraheliotropic movements, finer tuning of water-use efficiency, a lower transpiration rate, higher leaf area and higher pod abortion to accomplish the maximum possible grain production under continued drought conditions.

Progress in soybean functional genomics over the past decade.

Abstract: Soybean is one of the most important oilseed and fodder crops. Benefiting from the efforts of soybean breeders and the development of breeding technology, large number of germplasm has been generated over the last 100 years. Nevertheless, soybean breeding needs to be accelerated to meet the needs of a growing world population, to promote sustainable agriculture and to address future environmental changes. The acceleration is highly reliant on the discoveries in gene functional studies. The release of the reference soybean genome in 2010 has significantly facilitated the advance in soybean functional genomics. Here, we review the research progress in soybean omics (genomics, transcriptomics, epigenomics and proteomics), germplasm development (germplasm resources and databases), gene discovery (genes that are responsible for important soybean traits including yield, flowering and maturity, seed quality, stress resistance, nodulation and domestication) and transformation technology during the past decade. At the end, we also briefly discuss current challenges and future directions.

Soybean Seed Vigor: Uniformity and Growth as Key Factors to Improve Yield

Abstract: Emergence uniformity and the time required for emergence are essential factors for obtaining highly productive potential in plants. Factors such as sowing depth and soil moisture affect uniformity and emergence, but little is known about the impacts of seed vigor. Thus, we determined the impacts of seed vigor on uniformity and growth as well as development and yield in soybean (Glycine max [L.] Merrill) plants. The treatments consisted of four vigor levels (89%, 57%, 47%, and 43%) obtained by accelerated aging, in a randomized block design, with five replicates at three sites. Seeds with the highest vigor level showed higher uniformity and faster emergence. Dominated plants through their phenotypic plasticity modify stem diameter and internode length. The plants that emerged earlier had a larger leaf area in the three stages (V1, V4, and R2), allowing them to accumulate more photoassimilates in the initial stages. Consequently, these plants exhibited an increase in yield components, especially in the number of fertile nodes and the number of pods per plant, making them more productive.

Coordinated mechanisms of leaves and roots in response to drought stress underlying full-length transcriptome profiling in Vicia sativa L

Abstract: Common vetch (Vicia sativa L.) is an important self-pollinating annual forage legume and is of interest for drought prone regions as a protein source to feed livestock and human consumption. However, the development and production of common vetch are negatively affected by drought stress. Plants have evolved common or distinct metabolic pathways between the aboveground and underground in response to drought stress. Little is known regarding the coordinated response of aboveground and underground tissues of common vetch to drought stress. Our results showed that a total of 30,427 full-length transcripts were identified in 12 samples, with an average length of 2278.89 bp. Global transcriptional profiles of the above 12 samples were then analysed via Illumina-Seq. A total of 3464 and 3062 differentially expressed genes (DEGs) were identified in the leaves and roots, respectively. Gene Ontology (GO) enrichment analyses identified that the dehydrin genes and Δ1-pyrroline-5-carboxylate synthase were induced for the biosynthesis of proline and water conservation. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis results indicated that the DEGs were significantly enriched in hormone signal transduction, starch and sucrose metabolism, and arginine and proline metabolism, and various drought response candidate genes were also identified. Abscisic acid (ABA; the AREB/ABF-SnRK2 pathway) regulates the activity of AMY3 and BAM1 to induce starch degradation in leaves and increase carbon export to roots, which may be associated with the drought stress responses in common vetch. Among the co-induced transcription factors (TFs), AREB/ABF, bHLH, MYB, WRKY, and AP2/ERF had divergent expression patterns and may be key in the crosstalk between leaves and roots during adaption to drought stress. In transgenic yeast, the overexpression of four TFs increased yeast tolerance to osmotic stresses. The multipronged approach identified in the leaves and roots broadens our understanding of the coordinated mechanisms of drought response in common vetch, and further provides targets to improve drought resistance through genetic engineering.