921 resultados para norms
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The aim of this study was to estimate genetic parameters for milk yield (MY) in buffaloes using reaction norms. Model included the additive direct effect as random and contemporary group (herd and year of birth) were included as fixed effects and cow age classes (linear) as covariables. The animal additive direct random effect was modeled through linear Legendre polynomials on environment gradient (EG) standardized means. Mean trends were taken into account by a linear regression on Legendre polynomials of environmental group means. Residual variance was modeled trough 6 heterogeneity classes (EG). These classes of residual variance was formed : EG1: mean = 866,93 kg (621,68 kg-1011,76 kg); EG2: mean = 1193,00 kg (1011,76 kg-1251,49 kg); EG3: mean = 1309,37 kg (1251,49 kg -1393,20 kg); EG4: mean = 1497,59 kg (1393,20 kg-1593,53 kg); EG5: mean = 1664,78 kg (1593,53 kg -1727,32kg) e EG6: mean = 1973,85 kg (1727,32 kg -2422,19 kg).(Co) variance functions were estimated by restricted maximum likelihood (REML) using the GIBBS3F90 package. The heritability estimates for MY raised as the environmental gradient increased, varying from 0.20 to 0.40. However, in intermediate to favorable environments, the heritability estimates obtained with Considerable genotype-environment interaction was found for MY using reaction norms. For genetic evaluation of MY is necessary to consider heterogeneity of variances to model the residual variance.
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Chemical analysis of leaves is an effective tool for detecting nutritional imbalances and providing data for fertilizer recommendations. Therefore, it is extremely important to establish criteria for interpreting these results. The DRIS (Diagnosis and Recommendation Integrated System) method is an alternative to the interpretation of results of leaf analysis as it allows the calculation of indexes for each nutrient, using its relations with others and comparing them with a reference population. Thus, we aimed to establish preliminary DRIS norms, by both Beaufils's and Jones's methods, and to derive critical levels and nutrient sufficiency ranges in the leaf tissue for Pera orange, by studying a commercial crop in the growing conditions of the Sao Paulo state. The methods (Beaufils and Jones) differed in the limiting nutrients in the Pera orange orchard. The use of regional norms must be prioritized because of differences between the management methods applied. In the methods used, the nutrients that had a greater number of concordant cases in decreasing order: Mn > Mg > B > N > Cu > Fe > Zn > K > P > Ca. Amplitudes related to the DRIS methods used were narrower than the conventional literature.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)