Antônio Marcos Rosado

Enraizamento de miniestacas de clones híbridos de Eucalyptus globulus

The objective of this study was to evaluate the effect of the growth regulator indol butiric acid (IBA) on the rooting of apical and intermediate mini-cuttings of Eucalyptus urophylla x E. globulus and Eucalyptus grandis x E. globulus clones. The mini-cutting rooting was carried out for 30 days in acclimatized greenhouse and after the cuttings were transferred to shade house, where they remained for 10 days. The experimental design was in random blocks with a triple factorial arrangement constituted by two types of mini-cuttings (apical and intermediate), three IBA concentrations (0, 2000 and 4000 mg L -1 ) and eleven clones, in three repetitions, composed of 12 mini-cuttings per repetition. The IBA did not affect the characteristics evaluated. The survival and rooting of apical mini-cuttings were significantly higher. There was significant difference among clones regarding the evaluated variables, except for survival after 30 days in greenhouse.

Seleção simultânea de clones de eucalipto de acordo com produtividade, estabilidade e adaptabilidade

The objective of this work was to estimate genetic parameters and to determine the efficiency of the simultaneous selection of eucalyptus clones based on yield, stability, and adaptability. Twenty-one clones, with 36 months of age, from the genetic breeding program of the company Cenibra were used. The experiment was done in a randomized complete block design, in four environments, with 21 replicates of one plant per plot. The clones were evaluated as to the variables: diameter at breast height, plant height, and total volume with bark. The genetic parameters were estimated using the mixed model procedure (REML/BLUP), and selection was based on the harmonic mean of the relative performance of the genetic values (HMRPGV), with three strategies: selection based on the predicted genetic gain, considering the average performance of genotypes in all environments (without interaction effect) or the performance on each environment (with interaction effect); and simultaneous selection based on productivity, stability, and adaptability. Environment particularities influenced the phenotypic expression of the clones. The heritability estimates indicated good perspectives for selecting clones with high yield, stability, and adaptability. Simultaneous selection optimizes clone selection and can be used in the construction of breeding populations and in the recommendation of genetic materials for commercial plantations.

Ganhos genéticos preditos por diferentes métodos de seleção em progênies de Eucalyptus urophylla

The objective of this work was to evaluate genetic parameters and to compare predicted gains using different selection methods in half-sib families of Eucalyptus urophylla. Within and between selection, combined selection and selection based on mixed model equations (REML/BLUP) were used for the traits diameter at breast height, total height and total volume with bark. The progeny test used consisted of 100 55-month-old half-sib families distributed in a 3x2-m spacing, in randomized complete block design with five replicates. The progenies showed significant genetic variability and high heritability for the studied traits, which indicates high genetic control and favorable conditions for selection. All the methods tested were efficient in eucalyptus breeding. However, the combined selection and the selection based on mixed models (BLUP) provided gains significantly larger than those obtained with within and between selections, and were more efficient in the selection of the best individuals in the population.

Detection of QTL associated with rust resistance using IBD-based methodologies in exogamic Eucalyptus spp. populations

In Brazil the rust caused by Puccinia psidii Winter stands out as the most important disease of eucalyptus. The use of resistant genotypes is the main control method, which makes the detection of markers linked to rust resistance essential to the selection of resistant genotypes. In this study, an F1 progeny of 131 plants from interspecific crossings of Eucalyptus was used to identify markers linked to resistance genes for this pathogen. An integrated map was constructed for linkage group three based on microsatellite markers. For QTL mapping two methodologies based on alleles identical-by-descent (IBD) were used: single marker analysis of Haseman and Elston and the interval mapping procedure of Fulker and Cardon. Both methods showed significant association for the Embra 125 marker.The QTL that explained 42 % of the phenotypic variation was mapped to 0.02 cM of this marker by the Fulker and Cardon. Marker Embra 125 has potential use in assisted selection, thus increasing the efficiency of the selection of resistant genotypes.

Mapping of QTLs related with wood quality and developmental characteristics in hybrids (Eucalyptus grandis x Eucalyptus urophylla)

n The present work aimed to characterize and identify QTLs for wood quality and growth traits in E. grandis x E. urophylla hybrids. For this purpose a RAPD linkage map was developed for the hybrids (LOD=3 and r=0.40) containing 52 markers and 12 linkage groups. Traits related to wood quality and growth were evaluated in the QTL analyses. QTL analyses were performed using chi-square tests, single-marker, interval mapping and composite interval mapping analyses. All approaches led to the identification of similar QTLs associated with wood density, cellulose pulp yield and percentage of extractives, which were detected and confirmed by both the interval mapping and composite interval mapping methodologies. Some QTLs regions were confirmed only by the composite interval mapping methodology: percentage of soluble lignin, percentage of insoluble lignin, CBH and total height. Overlapping QTLs regions were detected, and these, can be the result of major genes involved in the regulation and control of the growth traits by epistatic interactions. In order to evaluate the effect of early selection using RAPD molecular data, molecular markers adjacent to QTLs were used genotype selection. The analysis of selection differential values suggests that for all the traits the phenotypic selection at seven years should generate larger genetic gains than early selection assisted by molecular markers and the combination of the strategies should elevate the selection efficiency.

Predição de ganhos genéticos em progênies de polinização aberta de Eucalyptus urograndis cultivadas em diferentes ambientes e submetidas a diferentes procedimentos de seleção

The objective of this study was to compare the genetic gain estimates obtained by different selection strategies for identification of Eucalyptus grandis x Eucalyptus urophylla genotypes with specific environmental adaptation. The genetic progress obtained by mass selection, stratified mass selection, selection among and within families and combined selection was evaluated in thr ee contrasting environments. Variance analysis showed a significant difference at 1% of probability according to the F test among the different genotypes evaluated in these three environments. This genetic divergence was observed in all the evaluated traits: diameter at breast height, plant height and wood volume, allowing inferring the existence of genetic variability among families. The hybrid population studied presents good yield potential and genetic variability to be explored by selection. The selection methods showed similar estimates of genetic progress, supporting the decision to use the most practical strategies.

Seleção de progênies de eucalipto pelo índice Z por MQM e Blup

Abstract – The objective of this work was to evaluate the efficiencyof the Z index (sum of standardized variables index), in the selection of full‑sib progenies between Eucalyptus grandis and Eucalyptus urophylla via least square method (LSM) and best linear unbiased prediction (Blup) procedures. The experiments were carried out in two soil types and environments, in a randomized complete block design, with fivereplicates, eight plants per plot and 3x2 m spacing. Wood average annual increment, basic density, screened pulp yield, and effective alkali were evaluated for three‑year‑old plants. The Z index was obtained for each plant in order to compare the efficiencyof selection for the best progenies by LSM and Blup procedures. Subsequently, the predicted averages to Z index were obtained and ranked. For comparison, the classic index was used. The coincidence among the best progenies selected by classical and Z index was good. However, the Z index allows a graphic display that enables to check in which characters the progenie has a disability. There is no difference between the best progenies selected by the Z index via LSM and Blup.Index terms:

ESTRATÉGIAS NA SELEÇÃO SIMULTÂNEA DE VÁRIOS CARACTERES NO MELHORAMENTO DO Eucalyptus

The aim of this study was i) to compare the results obtained with the Z index (sum of standardized variables) in relation to the classical (Smith, 1936; HAZEL, 1943) and rank sum indexes (Mulamba and MOCK, 1978) by means of the growth and wood technology traits and ii) to verify the progeny x environment interaction in simultaneous multiple trait selection, based on the Z index. Thus, we used a full sib progeny test of Eucalyptus urophylla and Eucalyptus grandis evaluated in two locations in the municipality of Ipaba, Minas Gerais state. At three years of age, the following traits were evaluated: average yearly increase of wood, wood density, refined pulp yield and effective alkali. There was good agreement in the progeny selection by the indexes. Thus, use of the Z index of standardized variables is a good option in simultaneous selection of multiple traits in the forestry sector through its ease of application and, above all, interpretation of results. The mentioned index revealed efficient in the study of the genotypes x environments interaction.

EFFECTIVENESS OF ASCORBIC ACID AND PVP IN THE ROOTING OF CLONAL MINI-CUTTINGS OF Eucalyptus urophylla x Eucalyptus grandis

The objective of this study is to evaluate the effectiveness of the antioxidants ascorbic acid and polyvinylpyrrolidone (PVP) in the rooting of mini-cuttings for three clones of Eucalyptus urophylla x Eucalyptus grandis. Mini-cuttings were gathered from a mini-clonal hedge which had been cultivated in concrete ducts containing washed sand. Five concentrations of each antioxidant were experimentally tested on each of the three clones (C1, C2 and C3). Assessments were done of mini-cutting survival and rooting rates when leaving the greenhouse and the shade house, as well as seedling survival and growth at age 50 days. Ascorbic acid was found to be beneficial to the mini-cuttings of the clone with a lower rooting percentage (C3), whereas PVP was found to be unbeneficial to the clones being studied.

EFEITO DO INTERVALO DE TEMPO ENTRE COLETA/PREPARO E ESTAQUEAMENTO NO ENRAIZAMENTO DE MINIESTACAS DE CLONES DE Eucalyptus urophylla x Eucalyptus grandis

This study aimed to assess the effects of the time interval between the collection/preparation and plantation on the rooting of minicuttings of four Eucalyptus urophylla x Eucalyptus grandis clones. The experimental design used was entirely randomized, bi-factorial and arranged with sub-divided plots, being time intervals in plots (0, 2 and 4 hours) and the clones in subplots (C 1 , C 2 , C 3 and C 4 ), with three replications of 192 plants each. The rooting and the survival of minicuttings in the greenhouse exit and in the shade house, the survival, the growth and the root system quality of 50-day-old seedlings were assessed. Among the four clones studied, it was observed, in three ones, that storage periods of the minicuttings above two hours caused significant reduction in the percentage of rooting and in the survival of 50-day-old seedlings . However, the clone C 2 presents the most efficient technique for rooting in the shade house exit and the survival of 50-day-old seedlings when their minicuttings are stored for 2.3 and 2.5 hours, respectively; as much as it presents greater height growth , when the minicuttings were stored during 4 hours. In all clones, those seedlings from minicuttings stored during 4 hours present lower quality of root system than plants obtained from cuttings with 0 and 2 hours of storage.