SISTEMA DE REPRODUÇÃO E DIVERSIDADE GENÉTICA EM PLANTIO DE Chorisia speciosa St. Hil
DOI:
https://doi.org/10.24278/2178-5031.2002142410Keywords:
recupcration planting, regeneration, effective population size, isozymes, electrophorcsisAbstract
Environmental reforestation programs require the knowledge of the species genetic potential since this allows their adaptation and evolutionary course. This paper aims to evaluate the regenerative genetic potential of a species, Chorisia speciosa, established in Iracenópolis, São Paulo State. The plantation was composed by 120 fourteen-years-old trees occupying an arca of 20ha, being C. speciosa represented by 52 trees of an unknown provenance. ln order to characterize the outcrossing rate and genetic diversity, samples of open-pollinated progenies were sampled in 10 trees, by collecting 10 seeds per tree. The mean multilocus outcrossing rate (0.975 ± 0.033) was high, characterizing thc species as alogamus. Test of homogeneity in ovules anel pollen allele frequencies anel correlation of outcrossed paternity (r = 0.334 ± 0.102) have shown that outcrossing we not carried out at random, jeing the families composed by mixture of half-sibs and full-sibs. The differences among multilocus outcrossing rate and single locus outcrossing rate has suggested that there was mating among relatives, (5.5%). The fixation index within population (F) was smaller in adults (0.002 ± 0.001) in relation to the families (0.129 ± 0.198), showing the possibility of selection occurrence against homozigotes. An F of 0.129 suggests that the parents of the present generation were rei ateei on average as hal fisibs. The effective population size (N.) estima teci f rom heterozigosity reduction between families anel parental generation showed the plantation was established for seed collected from only a tree, where the outcrossing have not taken place randomly, being the families mixture of hall-sibs and full-sibs.
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