Correlação da resistência ao cisalhamento e propriedades fisicoquimicas como critério de seleção de acessos do gênero paspalum para forrageiras
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Data
2019-07-16
Autores
Barros, Juliana da Silva
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Universidade Estadual Paulista (Unesp)
Resumo
Os programas de melhoramento de gramíneas forrageiras nas fases iniciais geralmente envolvem grande número de acessos, demandando tempo, esforço e investimento financeiro, evidenciando a necessidade de análises alternativas. Neste contexto a resistência ao cisalhamento (RC) surge como alternativa aos protocolos relacionados às análises de fibra em detergente neutro (FDN). Folhas de 13 acessos de Paspalum de duas espécies (P. atratum e P. regnellii) foram submetidas à análises de RC usando o texturômetro Warne Bratzer. Também analisou-se FDN, FDA, lignina e digestibilidade “in vitro” da matéria seca (DIVMS). Medidas morfológicas (peso, largura, área foliar e índice de área foliar) foram realizadas para padronização da RC por unidade de tecido foliar. O delineamento experimental foi em blocos completos ao acaso, com quatro repetições e oito cortes realizados ao longo de dois anos agrícolas. A técnica foi avaliada quanto a sua capacidade de detectar diferenças entre acessos das mesmas espécies e as correlações dos acessos e as variáveis estudadas ao longo de dois anos. Os resultados demostraram haver correlações entre RC e FDN (r=0,49) e correlações negativas entre digestibilidade e RC (r=-0,55). Essas correlações foram mantidas quando as variáveis de força foram padronizados considerando as variáveis morfológicas, apresentando correlações positivas e fortes para densidade linear (r=0,52) e densidade por área foliar (r=0,56). A RC foi capaz de identificar diferença entre acessos da mesma espécie. Deste modo, a técnica pode ser usada nas fases iniciais de seleção de espécies do gênero Paspalum.
Forage grass breeding programs in the initial stages usually involve a large number of accesses requiring time, effort and financial investment, evidencing the need for alternative analyzes. In this context, shearing strength (SS) is an alternative to the protocols related to neutral detergent fiber analysis (NDF). Leaves of 13 accessions of Paspalum of two species (P. atratum and P. regnellii) were submitted to SS analysis using the Warne Bratzer texturometer®. Also analyzed NDF, ADF, lignin and dry matter “in vitro” digestibility (DMIV). Morphological measures (weight, width, leaf area and leaf area index) were also performed to standardize SS per unit of leaf tissue. The experimental design was in complete blocks at random, with four replications and eight cuts performed over two years agricultural. The technique was evaluated for its ability to detect differences between accesses of the same species and the correlations of accesses and variables studied over two years. The results showed correlations of SS and NDF (r =0,49) and negative correlations between digestibility and SS (r=-0,55). These correlations were maintained when the strength variables were standardized considering the morphological variables, presenting positive and strong correlations for linear density (r=0,52) and density per leaf area (r= 0,56). RC was able to identify differences between accessions of the same species. In this way, the technique can be used in the initial phases of selection of species of the genus Paspalum.
Forage grass breeding programs in the initial stages usually involve a large number of accesses requiring time, effort and financial investment, evidencing the need for alternative analyzes. In this context, shearing strength (SS) is an alternative to the protocols related to neutral detergent fiber analysis (NDF). Leaves of 13 accessions of Paspalum of two species (P. atratum and P. regnellii) were submitted to SS analysis using the Warne Bratzer texturometer®. Also analyzed NDF, ADF, lignin and dry matter “in vitro” digestibility (DMIV). Morphological measures (weight, width, leaf area and leaf area index) were also performed to standardize SS per unit of leaf tissue. The experimental design was in complete blocks at random, with four replications and eight cuts performed over two years agricultural. The technique was evaluated for its ability to detect differences between accesses of the same species and the correlations of accesses and variables studied over two years. The results showed correlations of SS and NDF (r =0,49) and negative correlations between digestibility and SS (r=-0,55). These correlations were maintained when the strength variables were standardized considering the morphological variables, presenting positive and strong correlations for linear density (r=0,52) and density per leaf area (r= 0,56). RC was able to identify differences between accessions of the same species. In this way, the technique can be used in the initial phases of selection of species of the genus Paspalum.
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Critérios de seleção, Morfologia, Planta forrageira