Escurecimento de grãos em feijão: parâmetros genéticos e fenotípicos, associação com tempo de cocção, seleção assistida por marcadores e obtenção de linhagens elite
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2015-03-31
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Universidade Federal de Goiás
Resumo
The breeding of common bean cultivars with Carioca grain, slow grain darken-ing,
upright plant architecture, and high yield has become a growing challenge. Slow grain
darkening will increase the storage time, providing flexibility for producers for the
time of sale, and consequently increasing profitability. Studies have demonstrated the
existence of genetic variability for this trait, allowing the selection of lines with slow
grain darkening. The objectives of this study were i) to estimate genetic and
phenotypic parameters of lines of four segregating common bean populations; ii)
select those with slow grain darkening, upright plant architecture and high yield; iii)
seek an association between slow darkening and cooking time of grains after storage;
iv) evaluate two induction methods of grain dark-ening and v) validate the markers
Pvsd-1158 and PVM02TC116, associated with grain darkening. The tested lines were
derived from four segregating populations resulting from crosses between the cultivar
BRSMG Madrepérola with slow grain darkening and the par-ents BRS Estilo, BRS
Cometa, BRS Notável, and CNFC 10429. Three trials were installed with 220 lines (55
per population), and 5 parents in a 5x15 triple lattice design, with plots of two 3-m
rows, at three locations. The experiments were conducted in the winter grow-ing
season 2012, one in Santo Antônio de Goiás and two in Brasilia. The traits grain yield,
plant architecture, grain darkening, 100-grain weight, and cooking time were
evaluated. The variance components and genetic and phenotypic parameters were
estimated, and the phenotypic, genetic and environmental correlation coefficients
between grain darkening and cooking time, 90 and 180 days after harvest. Induction
methods of accelerated and slow darkening were compared. From the markers Pvsd-
1158 and PVM02TC116, identi-fied as previously linked to the gene that controls grain
darkening, the frequency of recom-bination and selection efficiency of the markers
was estimated for each population and environment and in the mean of the
environments. For slow grain darkening, the estimates of heritability, genetic variance
and expected gain with selection were high, indicating good chances of successful
selection. For yield, plant architecture and commercial grain size, the estimates of
heritability and genetic variance were high, but indicated no high gains with
simultaneous selection. Lines with slow grain darkening were obtained from the four
populations; the highest number of lines that combined slow darkening with upright
plant architecture, high yield, and commercial grain size were derived from the
crosses BRSMG Madrepérola x BRS Estilo and BRSMG Madrepérola x BRS Cometa. No
im-portant genetic correlation between grain darkening and cooking time was
identified, there-fore, light-colored grains do not indicate a short cooking time. The
induction methods of slow and accelerated darkening, provide similar information in
the discrimination of lines with slow and regular darkening. The estimates of the
recombination frequency for marker Pvsd-1158 were always low, indicating the close
linkage of this marker to the gene that controls slow darkening, and were stable in
the different environments and populations. Marker PVM02TC116 however was not
polymorphic in three of the four populations. The recombination frequency of this
marker in the polymorphic population was high, showing that it is unsuitable for
marker-assisted selection for grain darkening.
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ALVARES, R. C. Escurecimento de grãos em feijão: parâmetros genéticos e fenotípicos, associação com tempo de cocção, seleção assistida por marcadores e obtenção de linhagens elite. 2015. 134 f. Tese (Doutorado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2015.