Crescimento de clones de eucalipto em diferentes arranjos experimentais
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Data
2021-07-23
Autores
Silva, Ygor Antonio Lima da
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Universidade Estadual Paulista (Unesp)
Resumo
O Brasil é referência mundial em produção de madeira a partir de florestas comerciais de eucalipto. Os programas de melhoramento genético desse grupo de espécies demandam grandes áreas experimentais. Dessa forma, estudos sobre tamanho de parcelas experimentais são importantes para a correta identificação e seleção de genótipos superiores. Assim, o objetivo deste trabalho foi avaliar a influência de arranjos experimentais (forma de parcelas) no crescimento e classificação de clones de eucalipto. Foram instalados três experimentos em delineamento de blocos ao acaso, com 10 clones de eucalipto, sendo um experimento para cada forma de parcela: parcela de planta única, com 20 repetições de uma planta; parcela linear, com seis repetições de cinco plantas e parcela retangular, com três repetições de 21 plantas (3 linhas de 7 plantas). Aos 32, 36, 42 e 48 meses de idade foram avaliados o diâmetro à altura do perímetro (DAP), volume de madeira e a sobrevivência. Os dados foram analisados por modelos mistos, inicialmente para cada forma de parcela e, posteriormente, considerando-se conjuntamente as três formas de parcela. Foram estimados parâmetros genéticos e na análise conjunta procedeu-se ao estudo da adaptabilidade e estabilidade pelo método da Média Harmônica da Performance Relativa dos Valores Genotípicos (MHPRVG). Os principais resultados indicam que os clones diferem entre si denotando a existência de variabilidade genética e a possibilidade de seleção; os caracteres analisados encontram-se sob baixa influência ambiental; a interação clone x forma de parcela foi não significativa para os três caracteres analisados, indicando comportamento semelhante dos clones independentemente da forma de parcelas; os métodos de análise, Blup individual na análise conjunta ou a MHPRVG proporcionaram resultados semelhantes na classificação dos clones.
Brazil is a world reference in the wood production from commercial eucalypt forests. The genetic improvement programs of this group of species demand large experimental areas. Thus, studies on the size of experimental plots are important for the correct identification and selection of superior genotypes. Thus, the objective of this work was to evaluate the influence of experimental arrangements (plot shape) on the growth and classification of eucalyptus clones. Three experiments were installed in a randomized block design, with 10 eucalyptus clones, with one experiment for each shape of plot: single treet plot, with 20 replicates of one plant; linear plot, with six replicates of five plants and rectangular plot, with three replicates of 21 plants (3 rows of 7 plants). At 32, 36, 42 and 48 months of age, the diameter at breast height (DBH), wood volume and survival were evaluated. The data were analyzed by mixed models, initially for each shape of plot and then considering the three shape of plot together. Genetic parameters were estimated and the joint analysis proceeded to the study of adaptability and stability by the Harmonic Mean of Relative Performance of Genotypic Values (HMRPGV) method. The main results indicate that the clones differ from each other, denoting the existence of genetic variability and the possibility of selection; the characters analyzed are under low environmental influence; the interaction clone x plot shape was not significant for the three characters analyzed, indicating similar behavior of the clones regardless of the shape of plots; analysis methods, individual Blup in joint analysis or HMRPVG provided similar results in the classification of clones.
Brazil is a world reference in the wood production from commercial eucalypt forests. The genetic improvement programs of this group of species demand large experimental areas. Thus, studies on the size of experimental plots are important for the correct identification and selection of superior genotypes. Thus, the objective of this work was to evaluate the influence of experimental arrangements (plot shape) on the growth and classification of eucalyptus clones. Three experiments were installed in a randomized block design, with 10 eucalyptus clones, with one experiment for each shape of plot: single treet plot, with 20 replicates of one plant; linear plot, with six replicates of five plants and rectangular plot, with three replicates of 21 plants (3 rows of 7 plants). At 32, 36, 42 and 48 months of age, the diameter at breast height (DBH), wood volume and survival were evaluated. The data were analyzed by mixed models, initially for each shape of plot and then considering the three shape of plot together. Genetic parameters were estimated and the joint analysis proceeded to the study of adaptability and stability by the Harmonic Mean of Relative Performance of Genotypic Values (HMRPGV) method. The main results indicate that the clones differ from each other, denoting the existence of genetic variability and the possibility of selection; the characters analyzed are under low environmental influence; the interaction clone x plot shape was not significant for the three characters analyzed, indicating similar behavior of the clones regardless of the shape of plots; analysis methods, individual Blup in joint analysis or HMRPVG provided similar results in the classification of clones.
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Plantas Melhoramento genético, Eucalipto, Interação genótipo-ambiente