PHENOTYPIC MODELS OF COMPETITION FOR Pinus taeda L GENETIC PARAMETERS ESTIMATION

Abstract

ABSTRACT:The objective of this study was to evaluate the efficiency of the phenotypic models of competition, through spatial analysis in the genetic evaluation of Pinus taeda L progenies. For this, four competition covariates were used to adjust the phenotypic values in a P. taeda progeny test installed in four different locations in the state of Santa Catarina. The test was implemented in randomized block design, with seven repetitions, linear plots containing six plants per plot in 2.5 m x 2.0 m spacing. The test installed in sites A, B, and D present 63 families and site C 53 families. At nine years old, the diameter at the breast height was measured for all individuals. The presence or absence of competition was based on the residual autocorrelation coefficients, which had its significance tested by the Durbin-Watson test. In general, the use of covariates corrected the competition effect. The variances among and within plots, as well as the residual variation coefficient, were reduced. The classification by the genetic effect of the individuals in the progeny test was extremely altered for this data set with and without the use of covariates for sites A and D, as well as the genotype x environment interaction. The use of these two tools is of great importance in the analysis of data in P. taeda progeny tests, since the effects of competition can lead to mistakes in the selection of individuals and in the definition of improvement zones. MODELOS FENOTÍPICOS DE CONCORRÊNCIA PARA Pinus taeda L ESTIMAÇÃO DE PARÂMETROS GENÉTICOS RESUMO:O objetivo foi avaliar a eficiência dos modelos fenotípicos de competição, via análise espacial, na avaliação genética de testes de progênies de Pinus taeda L. Para isso foram utilizadas quatro covariáveis de competição para ajuste dos valores fenotípicos em um teste de progênies de P. taeda plantado em quatro diferentes locais no estado de Santa Catarina. O teste foi implantado em delineamento de blocos casualizados, com sete repetições, parcelas lineares de seis plantas e espaçamento de 2,5 m x 2,0 m. O teste instalado nos locais A, B e D possuem 63 famílias e no local C 53 famílias. Aos nove anos de idade foi efetuada a mensuração da variável diâmetro à altura do peito de todos os indivíduos. A presença ou não da competição foi baseada nos coeficientes de autocorrelação residual, que teve sua significância testada pelo teste de Durbin-Watson. No geral, o uso de covariáveis corrigiu o efeito da competição e as variâncias entre e dentro de parcela e o coeficiente de variação residual foram reduzidos. A análise espacial foi apropriada para validar a eficiência das covariáveis. A classificação pelo efeito genético dos indivíduos no teste de progênies foi extremamente alterada para o conjunto de dados com e sem o uso de covariáveis para os locais A e D, assim como a interação genótipo x ambiente. O uso dessas duas ferramentas é de suma importância na análise de dados em testes de progênies de P. taeda, pois os efeitos de competição podem conduzir a erros na seleção de indivíduos e n...

FEASIBILITY OF EARLY Pinus taeda L. SELECTION TO ASSESS GROWTH VARIABLES IN PROGENY TEST

“…Moderate individual heritability was observed at 6, 10 and 20 years; the highest value was observed at 10 years (0.40). Ishibashi et al (2017) recorded individual heritability values ranging from 0.24 to 0.43 in a 9-year-old settlement, in Rio Negrinho County (SC). Coutinho et al (2017) conducted a study aimed at investigating early selection in 8-and 15-year-old test progenies grown in Paraná State (Campo do Tenente, Sengés and Jaguariaíva counties) and found heritability values ranging from 0.08 to 0.26.…”

Variação genética em populações e progênies de Aroeira (Astronium urundeuva (M. Allemão) Engl.) no Bioma Cerrado

“…Betas shown that the covariate did not influence results as much, but that it could be important at thinning stage, by opening up more space, as spacing was already large in relation to the species initial establishment, since the individual cut no longer influences around. Still, covariates should not be completely discarded, since adequate choices for the experiment site, reduction of the experimental error variance are as important or more important than error caused by covariates (Leonardecz-Neto et al, 2003;Pavan et al, 2012;Ishibashi et al, 2017). Including HT in these measurements, along with DBH and Veq would be useful, despite the results found, since selection of growth characters must also be considered according to management and production needs.…”