Tiago Olivoto

REML/BLUP and sequential path analysis in estimating genotypic values and interrelationships among simple maize grain yield-related traits

Methodologies using restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) in combination with sequential path analysis in maize are still limited in the literature. Therefore, the aims of this study were: i) to use REML/BLUP-based procedures in order to estimate variance components, genetic parameters, and genotypic values of simple maize hybrids, and ii) to fit stepwise regressions considering genotypic values to form a path diagram with multi-order predictors and minimum multicollinearity that explains the relationships of cause and effect among grain yield-related traits. Fifteen commercial simple maize hybrids were evaluated in multi-environment trials in a randomized complete block design with four replications. The environmental variance (78.80%) and genotype-vs-environment variance (20.83%) accounted for more than 99% of the phenotypic variance of grain yield, which difficult the direct selection of breeders for this trait. The sequential path analysis model allowed the selection of traits with high explanatory power and minimum multicollinearity, resulting in models with elevated fit (R2 > 0.9 and ε < 0.3). The number of kernels per ear (NKE) and thousand-kernel weight (TKW) are the traits with the largest direct effects on grain yield (r = 0.66 and 0.73, respectively). The high accuracy of selection (0.86 and 0.89) associated with the high heritability of the average (0.732 and 0.794) for NKE and TKW, respectively, indicated good reliability and prospects of success in the indirect selection of hybrids with high-yield potential through these traits. The negative direct effect of NKE on TKW (r = -0.856), however, must be considered. The joint use of mixed models and sequential path analysis is effective in the evaluation of maize-breeding trials.

Parcelamento e fontes de nitrogênio na qualidade fisiológica de sementes de trigo

Diferentes fontes e manejos parcelados de nitrogenio podem aumentar a disponibilidade, a absorcao e a assimilacao deste nutriente pelas plantas, favorecendo o acumulo de N nos graos. No entanto, pouco se sabe sobre a influencia destes fatores na qualidade fisiologica de sementes de trigo (Triticum aestivum L). Dentro deste contexto, o objetivo deste trabalho foi avaliar a resposta de diferentes fontes e parcelamentos de nitrogenio aplicado em cobertura na qualidade fisiologica das sementes de trigo. O experimento foi conduzido em delineamento de blocos completos casualizados em esquema de parcelas subdivididas com tres cultivares de trigo (TBIO Mestre, TBIO Iguacu e Quartzo), tres fontes de nitrogenio (ureia, nitrato de amonio e ureia liquida) aplicadas em cinco parcelamentos (I: afilhamento; II: afilhamento e emborrachamento; III: afilhamento e florescimento; IV: emborrachamento e florescimento e V: afilhamento, emborrachamento e florescimento). O parcelamento do nitrogenio entre os estadios de emborrachamento e florescimento resulta em sementes com maior qualidade fisiologica, pois incrementa o percentual de germinacao em 4% e influencia positivamente os caracteres na primeira contagem de germinacao, comprimento de parte aerea, e massa seca de plântula. As fontes de nitrogenio, nitrato de amonia e a ureia fonte liquida, se equiparam com a ureia em relacao ao efeito na qualidade fisiologica das sementes, sendo alternativas interessantes para reduzir o custo de producao. As cultivares TBIO Mestre e Quartzo evidenciaram sementes com maior qualidade fisiologica, em funcao do maior comprimento de radicula e percentual de germinacao.

Nonlinear regression for description of strawberry (Fragaria x ananassa) production

ABSTRACT The aim of this study was to select growth models to describe strawberry (Fragaria x ananassa)fruit production. To do this, data on 16 treatments (combination of 2 cultivars [Albion and Camarosa], 2 origins [National and Imported], and 4 organic substrates mixed [70% crushed sugar cane residue + 30% organic compost, 70% crushed sugar cane residue + 30% commercial substrate, 70% burnt rice husk + 30% organic compost, and 70% burnt rice husk + 30% commercial substrate]) conducted in a Randomized Complete Block Design (RCBD) with 4 replicates were used. Different parameterizations of the Logistic, Gompertz, and von Bertalanffy models were adjusted for number and weight of fruits per plant (g) accumulated in multiple harvests. The model adjustment and parameter estimation were obtained by ordinary least squares, using a Gauss Newton algorithm. The selection of the best model was chosen by intrinsic and parametric nonlinearity. Among the adjusted nonlinear models, the best adjustment for both variables was achieved by the parameterization 2 of the Logistic model and parameterization 1 of the Gompertz model, because they had lower results with less parametric and intrinsic nonlinearity. However, care should be taken when using the Gompertz model because it tends to overestimate the production estimate and may cause misunderstandings in interpretation.

Variability, plot size and border effect in lettuce trials in protected environment

The variability within rows of cultivation may reduce the accuracy of experiments conducted in a complete randomized block design if the rows are considered as blocks, however, little is known about this variability in protected environments. Thus, our aim was to study the variability of the fresh mass in lettuce shoot, growing in protected environment, and to verify the border effect and size of the experimental unit in minimizing the productive variability. Data from two uniformity trials carried out in a greenhouse in autumn and spring growing seasons were used. In the statistical analyses, it was considered the existence of parallel cultivation rows the lateral openings of the greenhouse and of columns perpendicular to these openings. Different scenarios were simulated by excluding rows and columns to generate several borders arrangements and BASIC AREAS Article Variability, plot size and border effect in lettuce trials in protected environment Daniel Santos, Alessandro Dal’Col Lúcio*, Alberto Cargnelutti Filho, Sidinei José Lopes, Tiago Olivoto Universidade Federal de Santa Maria – Departamento de Fitotecnia – Santa Maria (RS), Brazil. *Corresponding author: adlucio@ufsm.br Received: Mar. 15, 2017 – Accepted: Aug. 14, 2017 also to use different sizes of the experimental unit. For each scenario, homogeneity test of variances between remaining rows and columns was performed, and it was calculated the variance and coefficient of variation. There is variability among rows in trials with lettuce in plastic greenhouses and the border use does not bring benefits in terms of reduction of the coefficient of variation or minimizing the cases of heterogeneous variances among rows. In experiments with lettuce in a plastic greenhouse, the use of an experimental unit size greater than or equal to two plants provides homogeneity of variances among rows and columns and, therefore, allows the use of a completely randomized design.

The effect of types and split of urea on yield indicators and yield components of maize

Maize is one of the most important cereals in the world. The productive potential of this crop is closely associated with nitrogen (N) fertilization, thus, studies focused on this subject are important in the development of cropping strategies. The aim of this work was to evaluate the effects of N split and different type of urea on important agronomic traits of the maize crop. A randomized complete block design in a 2×2+1 factorial treatment design with four replications was used. The factorial levels were composed of two types of urea (common and coated) and two nitrogen splits (V3 and V3+V8), plus the control treatment (without urea application). Important agronomic traits such as grain yield, biological productivity, and yield components were assessed. It was verified that there is no difference between the common or coated urea on grain yield and its components. On the other hand, the split of nitrogen into V3 and V8 stages is an efficient strategy to improve grain yield as well as important features as the number of rows per ears and harvest index. Thus, by using this management system farmers can achieve a more efficient nitrogen use.

Efeitos de enxofre e nitrogênio na qualidade industrial e no rendimento de grãos de trigo

The consumer market’s demand and requirement for wheat grains which present a satisfactory industrial quality have driven the demand for enhanced cropping systems, especially related to nutritional aspects. In this context, the purpose of this research was to evaluate how the sulfur supplementation and the usage of nitrogen (N) affect the baking quality and the yield of the wheat grain cultivar TBIO Itaipu®. A randomized block experimental design in factorial arrangement, with two sulfur managements (with and without) and four split nitrogen managements (I: 100% of N in the double ring; II: 30% of N in the tillering period + 40% of N in the double ring + 30% of N in the ear development; III: 50% of N in the tillering period + 50% of N in the double ring; IV: 50% of N in the double ring + 50% of N in the ear development period), arranged in four repetitions. Our results showed that the sulfur supplementation increased the gluten content, which has been positively correlated with the strength and extensibility of the bread dough. This had a positive influence on the technological parameters of the flour used for baking. The splitnitrogen fertilizer application (in double ring, tillering, and ear development) increased the wheat grain yield due to the greater number of tillers per plant and also of the wheat ears per square meter.

Japanese hybrid cucumber growth subjected to variation of temperature and luminosity

O objetivo foi avaliar o crescimento de mudas de pepineiro hibrido japones submetidas a variacao de temperatura e radiacao. O experimento foi conduzido no Laboratorio de Melhoramento Genetico e Producao de Plantas da Universidade Federal de Santa Maria, Campus de Frederico Westphalen – RS. O delineamento utilizado foi o de blocos ao acaso, organizados em esquema fatorial, sendo dois (ambientes) x 30 (dias de avaliacao), dispostos em cinco repeticoes. Os ambientes caracterizaram-se por uma câmara de crescimento com fotoperiodo e temperatura controlada (controlado), e ambiente com condicoes de temperatura e luminosidade natural (natural). As avaliacoes foram realizadas diariamente pelo periodo de 30 dias em cinco plantas de cada ambiente, avaliando-se o numero de folhas, altura de planta, comprimento da raiz, diâmetro do colo, massa verde da parte aerea, massa verde da raiz, massa seca da parte aerea, massa seca da raiz e a area foliar. Os resultados evidenciaram que temperaturas abaixo de 15 oC limitam o crescimento das mudas, principalmente quando ainda sao dependentes das reservas energeticas mantidas nos cotiledones. Indices de radiacao abaixo de 100 W m 2 s -1 reduzem a area foliar e a taxa de emissao de novas folhas. Abstract The objective was to evaluate the growth of Japanese hybrid cucumber seedlings submitted to the variation of temperature and radiation. The experiment was conducted at the Genetic Improvement and Plant Production Laboratory of the Federal University of Santa Maria , Campus of Frederico Westphalen , Rio Grande do Sul. It was used a randomized block design, arranged in a factorial arrangement, made up of two (environments) x 30 (days of evaluation), arranged in five replications. The environments were characterized by a growth chamber with photoperiod and controlled temperature, and environment with temperature and natural light conditions. The evaluations were performed daily for the period of 30 days in five plants of each environment, with respect to the: number of leaves, plant height, root length, stem diameter, green shoot biomass, green root biomass, dry shoot biomass, dry root biomass and leaf area. The results showed that temperatures below 15 °C limited the growth of seedlings, especially when they are still dependent upon energy stocks located in the cotyledons. Radiation levels below 100 W m 2 s -1 reduce the leaf area and the emission rate of new leaves.

AMBIENTE DE CULTIVO E SEUS EFEITOS AOS CARACTERES MORFOLÓGICOS E BROMATOLÓGICOS DA SOJA

O objetivo deste trabalho foi avaliar o desempenho agronomico de dois genotipos de soja com habito de crescimento indeterminado em dois ambientes de cultivo e verificar as relacoes lineares dos caracteres morfologicos e bromatologicos, buscando ganhos via melhoramento genetico. Os experimentos foram conduzidos na safra agricola 2013/2014. O delineamento experimental utilizado foi de blocos casualizados em esquema fatorial 2 x 2 sendo, dois ambientes de cultivo (Tenente Portela e Independencia – RS) e dois genotipos de soja com habito de crescimento indeterminado (FPS Solimoes RR e FPS Paranapanema RR), alocados de tres repeticoes. A analise de variância revelou significância para a interacao ambiente de cultivo x genotipo para os caracteres insercao do primeiro legume, altura de planta, e comprimento de internodio. Ausencia de interacao foi revelada pelo numero de legumes na haste principal, numero de legumes na ramificacao, numero de ramificacoes, comprimento das ramificacoes, numero de legumes com um grao, numero de legumes com dois graos, numero de legume com tres graos, massa de mil graos, rendimento de graos, percentuais de fibra bruta, material mineral, proteina bruta, carboidratos totais, carboidratos nao fibrosos e lipidios. O ambiente de cultivo Tenente Portela influencia positivamente o rendimento de graos de ambos os genotipos, e apresenta inter-relacoes significativas entre os caracteres morfologicos que influenciam o mesmo, sendo FPS Paranapanema RR superior para rendimento de graos. Os caracteres bromatologicos nao revelam diferenca significativa entre ambientes de cultivo e genotipos de soja com habito de crescimento indeterminado.