Residues of glyphosate and aminomethylphosphonic acid (AMPA) in genetically modified glyphosate tolerant soybean, corn and cotton crops / Resíduos de glifosato e ácido aminometilfosfônico (AMPA) em culturas de soja, milho e algodão geneticamente modificados tolerantes ao glifosato

Glyphosate is a broad-spectrum herbicide capable of controlling a wide range of weed. It uses could cause the occurrence of residues in conventional or genetically modified crops. For this purpose, grains (soybean and corn) and cotton seeds were sampled from commercial areas in 2012/2013 to 2017/2018 seasons in different Brazilian agricultural regions to monitor glyphosate residues levels and its metabolite (aminomethylphosphonic acid - AMPA) after different managements. The glyphosate residues levels in genetically modified corn (GM) ranged from no detected (ND) to 0.15 mg kg-1, in GM soybean values ranged from ND to 2.81 mg kg-1 and in GM cotton ranged from ND to 1.78 mg kg-1. AMPA residues levels indicated a correlation with the glyphosate residues. Glyphosate residues levels in soybean and corn grains and cotton seeds were within the Maximum Residue Limits (MRLs) established by ANVISA and Codex Alimentarius.(AU)

O glifosato é um herbicida de amplo espectro capaz de controlar uma grande diversidade de ervas daninhas e seu uso pode acarretar na ocorrência de resíduos, seja em culturas convencionais ou geneticamente modificadas. Sendo assim, amostragens de grãos de soja e milho e de sementes de algodão foram realizadas em áreas comerciais nas safras de 2012/2013 a 2017/2018 em diferentes regiões agrícolas brasileiras com o objetivo de monitorar os níveis de resíduos de glifosato e seu metabólito (ácido aminometilfosfônico - AMPA) após diferentes manejos. Os níveis de resíduos de glifosato em milho geneticamente modificados (GM) tolerante ao glifosato variaram desde não detectados (ND) a até 0,15 mg kg-1, em soja GM tolerante ao glifosato os valores variaram de ND a 2,81 mg kg-1 e em algodão GM tolerante ao glifosato os resultados se estabeleceram entre ND a 1,78 mg kg-1. Os valores de resíduos de AMPA indicaram correlação com os resíduos de glifosato. Os níveis de resíduos de glifosato em grãos de soja e milho e sementes de algodão ficaram dentro dos Limites Máximos de Resíduos (LMRs) preconizados pela ANVISA e Codex Alimentarius.(AU)

Accuracy and simultaneous selection gains for N-stress tolerance and N-use efficiency in maize tropical lines

Maize plants can be N-use efficient or N-stress tolerant. The first have high yields in favorable environments but is drastically affected under stress conditions; whereas the second show satisfactory yields in stressful environments but only moderate ones under optimal conditions. In this context, our aim was to assess the possibility of selecting tropical maize lines that are simultaneously N-stress tolerant and N-use efficient and check for differences between simultaneous selection statistical methods. Sixty-four tropical maize lines were evaluated for Nitrogen Agronomic Efficiency (NAE) and Low Nitrogen Tolerance (LNTI) response indices and two per se selection indices, Low Nitrogen Agronomic Efficiency (LNAE) and Harmonic Mean of Relative Performance (HMRP). We performed eight selection scenarios: LNAE; HMRP; Additive index; Mulamba-Mock index; and Independent culling levels. The last three was predicted by REML/BLUP single-trait and multi-trait using genotypic values of NAE and LNTI. The REML/BLUP multi-trait analysis was superior to the single-trait analysis due to high unfavorable correlation between NAE and LNTI. However, the accuracy and genotypic determination coefficient of NAE and LNTI were too low. Thus, neither single- nor multi-trait analysis achieved a good result for simultaneous selection nor N-use efficiency nor N-stress tolerance. LNAE obtained satisfactorily accurate values and genotypic determination coefficient, but its performance in selection gain was worse than HMRP, particularly in terms of N-use efficiency. Therefore, because of the superior performance in accuracy, genotypic determination coefficient and selection, HMRP was considered the best simultaneous selection methodology of the scenarios tested for N-use efficiency and N-stress tolerance.

Accuracy and simultaneous selection gains for N-stress tolerance and N-use efficiency in maize tropical lines

Maize plants can be N-use efficient or N-stress tolerant. The first have high yields in favorable environments but is drastically affected under stress conditions; whereas the second show satisfactory yields in stressful environments but only moderate ones under optimal conditions. In this context, our aim was to assess the possibility of selecting tropical maize lines that are simultaneously N-stress tolerant and N-use efficient and check for differences between simultaneous selection statistical methods. Sixty-four tropical maize lines were evaluated for Nitrogen Agronomic Efficiency (NAE) and Low Nitrogen Tolerance (LNTI) response indices and two per se selection indices, Low Nitrogen Agronomic Efficiency (LNAE) and Harmonic Mean of Relative Performance (HMRP). We performed eight selection scenarios: LNAE; HMRP; Additive index; Mulamba-Mock index; and Independent culling levels. The last three was predicted by REML/BLUP single-trait and multi-trait using genotypic values of NAE and LNTI. The REML/BLUP multi-trait analysis was superior to the single-trait analysis due to high unfavorable correlation between NAE and LNTI. However, the accuracy and genotypic determination coefficient of NAE and LNTI were too low. Thus, neither single- nor multi-trait analysis achieved a good result for simultaneous selection nor N-use efficiency nor N-stress tolerance. LNAE obtained satisfactorily accurate values and genotypic determination coefficient, but its performance in selection gain was worse than HMRP, particularly in terms of N-use efficiency. Therefore, because of the superior performance in accuracy, genotypic determination coefficient and selection, HMRP was considered the best simultaneous selection methodology of the scenarios tested for N-use efficiency and N-stress tolerance.(AU)

Correlação fenotípica entre componentes do rendimento de grãos de feijão comum (Phaseolus vulgaris L. ) / Phenotypic correlation between yield components of common bean (Phaseolus vulgaris L. )

O objetivo deste trabalho foi identificar qual é o componente principal do rendimento de grãos de feijão comum que apresenta menor sensibilidade ao efeito do ambiente, e que propicia maior consistência na expressão dos resultados, quando avaliados em diferentes locais. Os dados experimentais utilizados nas análises são provenientes de Ensaio de Valor cultivo e Uso (VCU) conduzidos nos municípios de Lages e de Chapecó. Os caracteres observados foram estande final de plantas; número de legumes por planta; número de grãos por legume; massa de 1.000 grãos e rendimento total de grãos em kg ha-1. O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições. As estimativas das correlações fenotípicas foram obtidas pelo método proposto por STEEL e TORRIE e particionadas em efeitos diretos e indiretos mediante a análise de trilha. Correlação inversa foi obtida para os caracteres massa de 1.000 grãos e número de grão por legume, revelando que os mesmos devem ser selecionados conjuntamente para obter ganho no caráter rendimento de grãos. Quando a seleção tem por objetivo aumentar o rendimento de grãos, para as condições ambientais de Chapecó a característica massa de 1.000 grãos pode ser utilizada, enquanto que em Lages o mais apropriado é utilizar o caractere número de legume por planta, pois apresentam consistência e estabilidade no desdobramento dos coeficientes de trilha.

This study aimed to identify which is the main component of grain yield of bean that that shows less sensitivity effect of the environment, and provides greater consistency in the expression of results when evaluated in different environments. Experimental data used in the analysis are derived from test of Cultivate and Use Value (VCU) conducted in Lages SC and Chapecó SC, South of Brazil. The characters observed were the final stand of plants, number of pods per plant; number of grains per pod, seed mass (g 1000 seed-1) and grain yield (kg ha-1). The experiment was conducted in a randomized block design, with four replications. Estimates of phenotypic correlations were obtained by the method proposed by STEEL and TORRIE and partitioned into direct and indirect effects through path analysis.The inverse correlation was obtained for the characters of seed mass and grain number per pod, revealing that they should be selected together to obtain gains in the yield character. When the selection is aimed at grain production, for Chapecó-SC the characteristic of seed mass can be used, where as in Lages-SC the character number of grains per pod is more appropriate. Characters seed mass and number of vegetable per pod showed high stability during the unfolding of the path coefficients, showing that they can be used in selecting genotypes with higher grain yield in different environments.