Variabilidade de plantas e progênies de populações naturais de Hancornia speciosa Gomes do Cerrado
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Data
2008-07-30
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Universidade Federal de Goiás
Resumo
The mangaba tree (Hancornia speciosa Gomes) is a fruit tree native from Brazil
with potential for domestication, due to its excellent smell, flavor and texture. However,
genetic conservation and breeding programs of these species are in an initial
developmental phase. This way, this research aimed to characterize trees and fruits of
natural populations of H. speciosa, as well as evaluate the distribution of phenotypic
variability among them; evaluate progenies of mangaba trees that compose the Escola de
Agronomia e Engenharia de Alimentos of Universidade Federal de Goiás (EA/UFG)
germplasm collection and estimate genetic parameters for the initial development of plants
in the field. Mangaba trees populations have been sampled in different locations of the
Brazilian Cerrado, including the states of Goiás, Tocantins, Mato Grosso, Mato Grosso do
Sul, and Bahia, totaling 109 mother plants of 35 populations of the botanic varieties
pubescens, gardneri, speciosa and cuyabensis. In relation to the trees, plant height, stem
perimeter, and number of fruits per plant were taken. From a sample of five fruits per
plant, individual measures have been taken, such as: length, diameter, weight, total weight
of seeds, average seed weight, pulp plus peel weight, seed number per fruit, pulp plus peel
yield, fruit shape and color and estimated production. Seeds from these mother plants were
used to install the EA/UFG mangaba germplasm collection in December 2005, in a
randomized complete block design with 57 treatments, four replications and one plant per
plot in a 5 m x 6 m spacing. The treatments were open pollination progenies, originated
from 28 natural populations. The characteristics plant height and stem basal diameter
were evaluated in all plants from January 2006 to August 2007, which resulted in 20 data
readings. Data from each plant has been transformed into growth rate. The analyses of
variance and the genetic parameter estimates were obtained to the growth rate and to the
data of latest reading of stem diameter and plant height. The progress was estimated by
simulating genetic selection in both sexes and maternal selection. In Cerrado conditions,
the results showed that H. speciosa mother plants show high levels of phenotypic variation
in fruit characters and most of this variation is among populations. There is a large
phenotypic variability in the varieties too. H. speciosa var. gardneri and H. speciosa var.
pubescens fruits are larger and heavier. The botanic variety gardneri shows gait more high
than the others varieties. In the varieties gardneri and pubescens predominate round shape
and light green color, while in speciosa and cuyabensis predominate oblong shape and dark
yellow and dark green colors, respectively. The varieties gardneri and pubescens stand out
as the most promising for selection based on fruit size and fruit weight. The mangaba tree
progenies of the germplasm collection of EA/UFG present high levels of genetic variation
in stem diameter and plant height and to their growth rates. Most of the genetic variation in
stem diameter is within populations and to plant height is among populations. H. speciosa
var. cuyabensis and H. speciosa var. gardneri show greater growth in stem diameter and
plant height. On account of the expected progress of selection, the collection can be used as seed orchard or clonal garden, without plant thinning, collecting seeds or buds of
superior plants. The maternal selection is recommended to maintain greater variability in
future breeding cycles, permitting progress from selection and maintaining the germoplasm
collection intact.
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Citação
GANGA, Rita Maria Devós. Plants and progenies variability of Hancornia speciosa natural
populations from Brazilian Cerrado. 2008. 126 f. Tese (Doutorado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2008.