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  • Author: E. Furlani x
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Individual, fruit, and annual variation in correlated mating in a Genipa americana population

Abstract

In this paper, we use six microsatellite loci to examine a spatially isolated population of Genipa americana in relation to mating system variation at the level of individual and among and within fruits, over two reproductive events. For our analysis, we sampled hierarchically among and within fruits open-pollinated seeds collected from 13 seed trees during the reproductive event in 2010 and 12 seed trees in 2011. The rate of mating among relatives (1-ts) was significantly greater than zero and different between the investigated reproductive events, indicating that some seeds are inbred. The estimate of fixation index (Fo) was significantly higher than zero for seeds from both reproductive events (2010: Fo = 0.258; 2011: Fo = 0.294), confirming that seeds present inbreeding, probably originated from mating among full-sibs. The multilocus paternity correlation within fruits (rp(w)) and among fruits (rp(a)) varied among seed trees and reproductive events. The rp(w) was significantly higher than rp(a) in both reproductive events, suggesting that it is more likely to find full-sibs within fruits (2010: 36.4%; 2011: 72.4%), than among fruits (2010: 18.9%; 2011: 12.8%). Due to the presence of inbreeding, mating among relatives and correlated mating, the within families coancestry coefficient (Θ) was higher and the variance effective size (Ne) lower than expected in open-pollinated families from panmictic populations (Θ = 0.125, Ne = 4). In practical terms for conservation programs, our results show the need to collect seeds from at least 60 seed trees to retain progeny arrays with a total effective size of 150.

Open access
Adaptability, stability, productivity and genetic parameters in slash pine second-generation families in early age

Abstract

The study was conducted to estimate the stability, adaptability, productivity and genetic parameters in Slash pine second-generation half-sib families, considering phenotypic traits in early age. Forty-four families from a first generation seed orchard in Colombo-PR, Brazil, were used in this study. Two progenies tests were established in a randomized complete block design. The first test was implemented in March 2009 in Ribeirão Branco, São Paulo state, containing 40 blocks, one tree per plot, 44 treatments (progenies) and 6 controls. Another test was implemented in Ponta Grossa, Paraná state, using the same experimental design and number of plants per plot, and with 24 treatments, 32 blocks. The growth traits evaluated were total height, diameter at breast height (dbh) and wood volume, within five years. The form traits evaluated were stem form, branch thickness, branch angle, number of branches, fork and fox tail five years after planting. Deviance analysis and estimates of stability, adaptability, productivity and genetic parameters were performed using the methods of best linear unbiased predictor (BLUP) and residual maximum likelihood (REML). There was significant variation among progenies for growth and form traits. Considerable genetic variation was detected mainly for wood volume. High coefficients of genetic variation and heritability showed low environmental influence on phenotypic variation, which is important for the prediction of genetic gain by selection. Crosses between different progenies individuals groups will be prioritized for obtaining heterotics genotypes and increase the probability of obtaining high specific combining ability.

Open access