Comparative analysis indicates a simple protocol for DNA extraction of the aromatic plant Lippia alba.

An efficient method of genomic DNA extraction that provides high quality and yield is a crucial pre-requisite and limiting factor in plant genetic analysis. However, pure genomic DNA can be challenging to obtain from some plant species due to their sugar and secondary metabolite contents. Lippia alba is an important aromatic and medicinal plant, chemically characterized by the presence of tannins, flavonoids, anthocyanins, and essential oils, which interfere with the extraction of pure genomic DNA. In this scenario, optimizing the extraction methods and minimizing the effects of these compounds are necessary. This study compares six plant DNA extraction protocols based on the CTAB method. The quality and quantity of DNA samples obtained were determined by physical appearance by electrophoresis in agarose gels and spectrophotometry. The results highlight the difficulty in obtaining pure and clear bands for all tested methods, except for the polyvinylpyrrolidone (PVP)-based protocol created by our team, which was the better option for obtaining high-quality genomic DNA of L. alba. We conclude that adding PVP-40 into DNA extraction buffers can optimize the DNA extraction of L. alba and indicate this protocol for DNA extraction from other aromatic plants.

Essential Oils of New Lippia alba Genotypes Analyzed by Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography (GC×GC) and Chemometric Analysis.

Lippia alba (Mill.) N. E. Br. (Verbenaceae) is an aromatic shrub whose essential oils have stood out as a promising source for application in several industrial fields. In this study, the essential oils chemical characterization of eight new L. alba genotypes was performed. The selected materials were collected from the Active Germplasm Bank of the Agronomic Institute and the essential oils were extracted by hydrodistillation. Flow-modulated comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) was employed for chemical characterization and evaluation of possible co-eluted compounds. In addition, the chemical analyses were submitted to multivariate statistical analyses. From this investigation, 73 metabolites were identified in the essential oils of the genotypes, from which α-pinene, ß-myrcene, 1,8-cineole, linalool, neral, geranial, and caryophyllene oxide were the most abundant compounds among the accessions. This is the first report disclosing α-pinene in higher amounts in L. alba (19.69%). In addition, sabinene, trans-verbenol, myrtenol, (E)-caryophyllene, α-guaiene, germacrene D, and α-bulnesene were also found in relevant quantities in some of the genotypes, and myrtenal and myrtenol could be well separated through the second dimension. Such results contributed to the understanding of the chemical composition of those new genotypes, being important to drive a future industrial applicability and studies in genetic breeding.

Genome composition and pollen viability of Jatropha (Euphorbiaceae) interspecific hybrids by Genomic In Situ Hybridization (GISH).

Interspecific hybridization is required for the development of Jatropha curcas L. improved cultivars, due to its narrow genetic basis. The present study aimed to analyze the parental genomic composition of F1 and BC1F1 generations derived from interspecific crosses (J. curcas/J. integerrima and J. curcas/J. multifida) by GISH (Genomic In Situ Hybridization), and the meiotic index and pollen viability of F1 hybrids. In F1 cells from both hybrids, 11 chromosomes of each parental was observed, as expected, but chromosome rearrangement events could be detected using rDNA chromosome markers, suggesting unbalanced cells. In the BC1F1, both hybrids had 22 chromosomes, suggesting that only n = 11 gametes were viable in the next generation. However, GISH allowed the identification of three and two alien chromosomes in J. curcas//J. integerrima and J. curcas//J. multifida BC1F1 hybrids, respectively, suggesting a preferential transmission of J. curcas chromosomes for both hybrids. Pollen viability in F1 hybrids derived from J. curcas/J. integerrima crosses were higher (82-83%) than those found for J. curcas/J. multifida (68%), showing post-meiotic problems in these last hybrids, with dyads, triads, polyads, and micronuclei as post-meiosis results. The here presented cytogenetic characterization of interspecific hybrids and their backcross progenies can contribute to the selection of the best genotypes for future assisted breeding of J. curcas.

Genetic parameter estimates and efficiency of three selection procedures in carrot breeding, variety Campinas

The potential for genetic breeding of the carrot variety "Campinas" was assessed through estimates of the genetic-statistical parameters of 16 traits of agronomic importance. The parameters were obtained from 102 half-sib progenies, harvested in a seed production field. Two experiments were carried out in Randomized Complete Blocks in the fall-winter and spring-summer planting periods. To compare the three selection methods, usually employed in population breeding genetics the expected genetic gains were estimated considering each blockor plot as strata, and mass selection between and within the half-sib progenies. Samples of 15 marketable roots per plot were evaluated at the individual level for the characters root length (RL) and root shape index (SI). A joint analysis of variance, weighted for the differences in number of replications between the experiments was performed for the six common traits. The results of the genetic parameter estimates of the single variance analysis indicated that the variety Campinas was best adapted to the fall-winter planting period. Heritabilities greater than 60 per cent were observed for the majority of traits assessed at the plot level. The selecction against the trait premature flowering (PF) may result in satisfactory genetic gain in the two environmental conditions because of the high genetic variability coefficients obtained. The percentage of marketable cylindrical roots (MCR) demonstrated an expected genetic gain per cycle of only 4.82 per cent in the fall-winter period, probably because it had already been selected, for various cycles, under these environmental conditions. On the other hand, in the spring-suminer planting period, the genetic gain was estimated to be 14.44 per cent. Total and marketable yields were high in the fall-winter period and low in the spring-summer period. For the traits RL and SI, assessed at the individual level, the stratified mass selection, considering each plot as strata, was less efficient in relation to the other proposed selection methods. Therefore it is concluded that breeding of the variety Caampinas, based on the performance of the half-sib progenies for root quality and yield is fairly promising within each planting period, but simultaneous selection for both periods is difficult.