Variabilidade Genética Em Progênies De Meios-Irmãos De Eucaliptos Para Tolerância Ao Frio1

Abstract

RESUMO -O objetivo deste estudo foi estimar os parâmetros genéticos quantitativos das progênies sob o efeito de geada, bem como determinar a interação genótipos x ambientes das progênies de Eucalyptus dunnii em dois locais de estudo. Os testes de progênies foram implantados em 2010, utilizando 20 progênies de polinização aberta de E. dunnii. Foram avaliados: altura de planta (ALT), diâmetro à altura do peito (DAP) e volume de madeira em metros cúbicos (VOL). Foram realizadas as análises estatísticas e descritivas, correlação fenotípica/ genotípica por local e análise de variância conjunta, sendo estimados os parâmetros genéticos. Foram detectadas diferenças significativas (p<0,05) entre progênies para as características silviculturais, o que sugere a possibilidade de melhoramento pela seleção. Pela análise conjunta, a interação progênies x ambientes (G x E) não apresentou diferença significativa, confirmando que as progênies superiores identificadas nos testes podem ser indicadas para ambos os locais. Os resultados de correlações genéticas e fenotípicas variaram de baixos a altos (0,23 a 1,0) para as características estudadas, sendo as correlações, em sua grande maioria, significativas (p<0,05), em que o DAP foi altamente correlacionado com o VOL. A população, por apresentar alta variação genética e controle genético das características, permite a obtenção de ganhos com a seleção entre as progênies.Palavras-chave: Eucalyptus dunnii; Melhoramento florestal; Geada. GENETIC VARIABILITY OF HALF SIBS EUCALYPTUS PROGENIES FOR COLD TOLERANCEABSTRACT -The aim of this study was to estimate quantitative genetic parameters of progenies under frost situations and to determine the interaction of genotype x environments for Eucalyptus dunnii progenies in two different sites. The progeny trials were set up in 2010, using 20 open pollination progenies of E. dunnii.The following variables were evaluated: plant height (HGT), diameter at breast height (DBH), and wood volume (VOL) in cubic meters. Descriptive and statistical analysis were used as well as phenotypic/genotype correlation by location and joint variance analysis and the genetic parameters were estimated. Significant differences were detected (p<0,05) among progenies for silvicultural characters, suggesting the possibilities for selection gain. By the joint analysis, the interaction of progenies x environments (P x E) did not show significant differences, confirming that the superior progenies identified in the tests can be used for both studied locations. The genetic and phenotypic correlations results ranged from low to high (0.23 to 1.0) values for the studied characters, and the great majority of correlations were significant (p<0,05) in which the diameter at breast height was highly correlated with volume. Because of high genetic variability and genetic control of the characters, the population allows to obtain gains with selection between in the progenies.

Early selection in Eucalyptus camaldulensis Dehnh. progenies in Savanna, Brazil

“…The experimental variation coefficient (CV e %) demonstrates that good experimental precision and its estimates in the present work were around 20% (Table 2), values superior to those found by other authors in eucalyptus progeny tests, as in Freitas et al, (2009) at three years old and Moraes et al (2015) at 36 months old in different localities. However, the genetic variation presented a magnitude close to environmental variation, once the relative variation coefficient (CV r ) that expresses the relation between the experimental variation (CV e %) and the progeny variation coefficient (CV gi %) was close or equal to 1 (3 and 6 years old, respectively) ( Table 2), which evidenced a favourable situation for selection (Vencovsky and Barriga, 1992;Cruz et al, 2004).…”

Classification of the Initial Development of Eucaliptus Using Data Mining Techniques

“…Studies associated with a decrease in the temperature below the optimum temperature tend to reduce plant growth by limiting the production of wood and damaging the formation of homogeneous plantations (FLORIANI et al, 2013;GAVITO et al 2001;PENG;DANG 2003). In particular, young eucalyptus plants are more sensitive to low temperatures than adult plants, which can lead them to death because they are not completely established in the environment where they were planted (MORAES et al, 2015).…”

Genetic parameters estimates and visual selection for leaves production in Ilex paraguariensis

“…Another alternative would be to check through notes or other variable that represents the feature under selection. According Moraes et al (2015), positive genetic correlations and a high magnitude among the characteristics show that they can be regarded as a single case in the selection, when the direction of the selection is the same, without much injury to any of the features. No significant correlations indicate independence between them.…”