ABSTRACT
Açaí (Euterpe oleraceaMart.) -a common tropical palm has high social, economic, and environmental importance in the Amazon region. In the light of increasing exploration to obtain the fruit and heart of this palms, comprehensive studies are warranted for conservation and genetic improvement. Here, we characterized açaí accessions using phenological, morphological, and agronomic descriptors and random amplified polymorphic DNA (RAPD)molecular markers for joint selection of accessions with greater productivity. Hundred accessions were analyzed using 18 morphoagronomic descriptors and 13 RAPD markers. The spathe and inflorescence emission phases during flowering and fruiting showed seasonality. Based on the coefficient of variation and mean squared error, the accessions exhibited high variability in the tested morphoagronomic descriptors and were distributed into seven groups. Fruit, seed, and pulp weights were important descriptors for the distinction of accessions and identification of those with greater productivity. The accessions presented >85% similarity, and 85 accessions, distributed in nine subgroups, could not be differentiated using RAPD markers. There was no correlation between grouping based on morphometric descriptors and RAPD markers. Panicle weight was 3.9-9.0 kg in 15 accessions and 100-fruit pulp weight was 35-50 g in six accessions. Therefore, accessions with high productivity could be selected.
Subject(s)
Anthocyanins , Biomarkers , Euterpe/genetics , Euterpe/chemistryABSTRACT
To determine the appropriate replication numbers for selection and estimation of genetic parameters economically and with appropriate precision, 21 four-year-old half-sib progenies of taxi-branco (Sclerolobium paniculatum Vogel) were studied in a randomized block design plantai in savanna belonging to the Agroforestry Research Center of Amapá-Embrapa Amapá, Amapá, Brazil. Estimates of genetic and phenotypic parameters were made for the growth characteristics height, diameter at breast height (DAP) and biomass, with the number of replications varying from two to ten. The efficiency of selection with different numbers of replications was compared to the experiment with ten replications. There was no advantage in using more than three replications, because the experimental precision did not change with more replications; the same occurred with the estimates of the genetic parameters and their associated standard deviations. The selection efficiency was high, showing almost full agreement between progenies selected using smaller replication numbers and with ten replications. This suggests that a smaller replication number (three) can be used, permiting the evaluation of larger numbers of progenies. This is a promising strategy to increase the chances of success in the selection process of Sclerolobium paniculatum.
Visando determinar o número adequado de repetições para seleção e estimar parâmetros genéticos com economicidade e precisão adequada, 21 progênies de meios-irmãos de Taxi-branco (Selerolobium paniculatum Vogel), com quatro anos de idade, foram analisadas em um experimento de blocos casualisados implantado no Campo Experimental do Cerrado, pertencente ao Centro de Pesquisa Agroflorestal do Amapá - Embrapa Amapá, no Estado do Amapá, Brasil. Foram obtidas estimativas dos parâmetros genéticos e fenotípicos para os caracteres de crescimento em altura, diâmetro à altura do peito (DAP) e biomassa, considerando os números de repetições variando de duas até dez. Foi estimada a eficiência da seleção com diferentes números de repetições relativamente ao experimento com dez repetições. Constatou-se não haver vantagem em empregar número de repetições superiores a três, visto que a precisão experimental praticamente não se alterou nos demais tratamentos, o mesmo ocorrendo com as estimativas dos parâmetros genéticos e seus desvios padrões associados. A eficiência de seleção foi alta, evidenciando uma concordância quase plena entre as progênies selecionadas com menor número de repetições comparativamente ao experimento com dez repetições, sugerindo que o emprego de menor número de repetições (três) e avaliação de maior número de progênies é uma estratégia promissora para aumentar as chances de sucesso no processo seletivo de Sclerolobium paniculatum
ABSTRACT
The efficiency of combined family/within family selection was evaluated in half-sib progenies of taxi-branco (Sclerolobium paniculatum Vogel) at the Cerrado Experiment Station, Embrapa Amapá, Amapá, Brazil, in a four-year-old 21 half-sib progeny trial in a randomized block design. Highly significant differences (p 1%) were found for three traits likely to show high genetic gain due to selection: diameter (DBH), biomass and height. Combined selection provided estimates of 30%, 42% and 51% gains, respectively, confirming that combined selection is a promising strategy in forest tree improvement. Effective population size must be estimated to assure genetic gain and preserve genetic variability.
São apresentados resultados da eficiência da seleção combinada em progênies de meios-irmãos de taxi-branco, com quatro anos de idade, relativamente ao esquema de seleção entre e dentro de famílias de meios-irmãos, As 21 progênies foram estudadas em um delineamento de blocos casualisados no Campo Experimental do Cerrado pertencente ao Centro de Pesquisa Agroflorcstal do Amapá - Embrapa Amapá, no Estado do Amapá, Brasil. As análises de variâncias apontaram diferenças significativas ao nível de 1% de probabilidade para os três caracteres avaliados, indicando serem grandes as chances de obtenção de sucesso com o processo seletivo. Ficou evidenciada a superioridade da seleção combinada sobre a seleção entre e dentro, visto que apresentou ganhos relativos superiores de 30%, 42% e 51% para DAP, biomassa e altura, respectivamente, indicando ser uma estratégia promissora no melhoramento genético de espécies florestais.