ABSTRACT
The objectives of this study were to identify the population structure and to assess the genetic diversity of maize inbreds. We genotyped 81 microsatellite loci of 90 maize inbreds that were derived from tropical hybrids and populations. The population structure analysis was based on a Bayesian approach. Each subpopulation was characterized for the effective number of alleles, gene diversity, and number of private alleles. We also performed an analysis of molecular variance and computed a measure of population differentiation (FST). The genetic distances were computed from the similarity index of Lynch and the dissimilarity measures proposed by Smouse and Peakall. The cluster analyses were based on the unweighted pair-group method using arithmetic averages and Tocher method. The clustering efficiency was assessed by the error rate of the discriminant analysis. We also performed a principal coordinates analysis. The population structure analysis revealed three tropical heterotic pools, which have been used by worldwide and Brazilian maize seed companies. The degree of genetic differentiation and of intra- and inter-population genetic diversity for these tropical heterotic pools are comparable to that observed for temperate and subtropical heterotic pools. The higher allelic frequency variation within each tropical heterotic pool and the high genetic diversity between the inbreds were evidence of heterotic groups within the main tropical heterotic pools.
Subject(s)
Genetic Variation , Genetics, Population , Hybridization, Genetic , Inbreeding , Zea mays/genetics , Alleles , Genetic Loci , Microsatellite Repeats , Polymorphism, GeneticABSTRACT
Macaw palm, Acrocomia aculeata is an oleaginous species of the Arecaceae family; it has been identified as one of the most promising plants for sustainable production of renewable energy, especially biodiesel. We developed an efficient protocol of genomic DNA extraction for A. aculeata using leaf and stipe tissues, based on the cationic hexadecyltrimethylammonium bromide method, and we evaluated the quantity, purity, and integrity of the resultant DNA. We also determined whether these procedures interfere with PCR amplification using SSR molecular markers. The lowest concentration of DNA was obtained from stipe tissues (135 ng/µL), while fresh leaf tissues provided the highest concentration of DNA (650 ng/µL). Good quality DNA was obtained from fresh leaf, lyophilized leaf, and stipe tissues (relative purity, 1.79-1.89 nm). Differences in quantity and quality of DNA extracted from different tissues did not interfere with general patterns of PCR amplification based on SSR markers.
Subject(s)
Arecaceae/genetics , DNA, Plant/isolation & purification , Plant Leaves/genetics , Polymerase Chain Reaction/methods , DNA, Plant/genetics , Genetic Markers , Microsatellite Repeats , Nucleic Acid Amplification Techniques , Sequence Analysis, DNAABSTRACT
Avaliaram-se, em delineamento inteiramente ao acaso com quatro repetições, os efeitos da idade de corte (83, 90, 97, 104, 111 e 118 dias) do triticale (X Triticosecale Wittimack) sobre o valor nutricional da forragem e sobre os padrões de fermentação e de qualidade da sua silagem. Houve incremento de 0,26 e decréscimo de 0,12 unidades porcentuais, respectivamente, nos teores de matéria seca (MS) e de proteína bruta (PB) da silagem, para cada dia adicional na idade de corte, sendo os maiores teores de MS obtidos de plantas cortadas aos 104 e 118 dias. Foi observado decréscimo de 0,03 unidades no pH das silagens para cada dia adicional na idade de corte do triticale. Os menores valores de pH e a menor taxa de proteólise foram observados de 97 a 118 dias de crescimento das plantas. Os parâmetros de degradação ruminal in situ da MS da forragem verde variaram de 82,2 a 91,7 por cento (degradabilidade potencial), de 1,9 a 3,3 por cento/h (taxa de degradação) e de 40,5 a 52,9 por cento (degradabilidade efetiva, sob taxa de passagem ruminal de 5 por cento/h). Na faixa de idade de corte do triticale de 83 a 118 dias em cultivo de inverno com irrigação por aspersão, na Zona da Mata de Minas Gerais, as silagens obtidas de plantas cortadas aos 104 e 111 dias de crescimento apresentam melhor qualidade de fermentação. A forragem obtida aos 83 dias de crescimento das plantas apresentou bom valor nutricional para ser utilizada sob condição de pastejo ou fornecida verde picada no cocho.
The effects of cutting age of triticale (X Triticosecale Wittimack) on its nutritional value, fermentation patterns, and quality of its silage were evaluated in a completely randomized design with four replications. Cutting ages were 83, 90, 97, 104, 111, and 118 days after sowing. There was an increase of 0.26 and a decrease of 0.12 percent unit on dry matter and crude protein contents, respectively, for each additional day in the cutting age. The highest values of dry matter were observed in plants cut at 104 and 118 days. It was observed a 0.03 percent unit decrease in the silage pH for each additional day in the cutting age. The lowest pH values and the lowest ammoniacal nitrogen concentration were observed from 97 to 118 days. The in situ ruminal degradation parameters of fresh forage ranged from 82.2 to 91.7 percent (potential degradability), from 1.9 to 3.3 percent/h (degradation rate), and from 40.5 to 52.9 percent (effective degradability under 5 percent/h of passage rate). When triticale was growth under irrigation in Zona da Mata during the winter and cut for silage, the best fermentation was observed at the plant ages of 104 and 111 days. At the age of 83 days, the plants showed good nutritional value to be grazed or fed as fresh cut to the animals.
