Nonpreference of the lace bug Leptopharsa heveae Drake & Poor (Heteroptera: Tingidae) for rubber tree clones

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Acerola's clones of industrial interest

In order to know which clone of acerola is better for acerola industrialization, we studied the pectin methylesterase (PME) specific activity, pectin content and vitamin C content in five different clones of acerola. The pectin yield varied from 1.37 to 2.99% and the highest content of pectin occurred in clones 3 and 5. Ascorbic acid varied significantly from 1157.5 to 1735.5 mg/100 g of pulp in the five clones. The highest content of vitamin C occurred in clone 4. The PME specific activity varied from 0.79 to 2.92 units g(-1)/g of pulp and the highest values occurred in clone 2. We also studied the optimum temperature and the optimum pH of this enzyme. Clones 1, 2, 4 and 5 showed optimum temperature at 90C. Clone 3 showed practically the same specific activity at all temperatures studied. Clones 1 and 4 showed an optimum pH of 9.0 and clone numbers 2, 3 and 5 showed a pH optimum at 8.5.

Acclimation to short-term low temperatures in two Eucalyptus globulus clones with contrasting drought resistance

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Multiple cytogenetic clones in a basal cell carcinoma

Chromosome analysis of short-term culture of a basal cell carcinoma showed five clonal chromosome abnormalities, t(9;14)(q12 or q13;p11), del(1)(q23 or q25), trisomy 5, trisomy 7, and monosomy X. In addition, several nonclonal structural and numerical changes were seen in the tumor cells.

Drought tolerance of two field-grown clones of Coffea canephora

We compared tolerance to soil drought of two field-grown clones of Coffea canephora (clone 46, drought-sensitive; and clone 120, drought-tolerant). Under irrigation, there were no marked differences between the clones in water relation parameters, gas exchange and total leaf area. Under rainfed conditions, clone 46 showed osmotic adjustment and increased tissue rigidity. These adjustments, however, were incapable of preventing substantial decreases in xylem pressure potential. By contrast, clone 120 did not exhibit osmotic adjustment, but was able to increase tissue elasticity and to maintain xylem pressure potentials to a greater extent than clone 46 (despite having twice the total leaf area of this clone). Stomatal conductance was lowered by drought in clone 120 but not in clone 46. Carbon assimilation per unit leaf area in both clones remained unaffected under stress. Long-term water use efficiency (WUE), as estimated through carbon isotope discrimination, was consistently greater in clone 120 than in clone 46. Because of these traits, clone 120 was better able to postpone dehydration and to maintain whole-tree photosynthesis. It is proposed that these features should decisively contribute to buffer its productivity in drought-prone areas. © 2002 Elsevier Science Ireland Ltd. All rights reserved.

Thermogravimetric studies of the decomposition kinetics of four different Hevea rubber clones using Ozawa's approach

Thermal degradation of natural rubber extracted from four different rubber clones of the Hevea brasiliensis species was investigated by thermogravimetry using Ozawa's approach to assess the kinetic parameters of the decomposition process. The results are discussed in terms of the order of reaction, kinetic parameters such as activation energy as a function of conversion degree, and thermal stability for each of the clones.

Parâmetros genéticos para caracteres de crescimento, de produção e tecnológicos da madeira em clones de Eucalyptus spp

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mapeamento da produtividade e perímetro do tronco de clones de seringueira em argissolo vermelho amarelo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Genetic divergence in Eucalyptus spp. clones by molecular RAPD markers

The genetic divergence in 20 Eucalyptus spp. clones was evaluated by multivariate techniques based on 167 RAPD markers, of which 155 were polymorphic and 12 monomorphic. The measures of genetic distances were obtained by the arithmetic complement of the coefficients of Jaccard and of Sorenso-Nei and Li and evaluated by the hierarchical methods of Single Linkage clustering and Unweighted Pair Group Method with Arithmetic Mean (UPGMA). Independent of the dissimilarity coefficient, the greatest divergence was found between clones 7 and 17 and the smallest between the clones 11 and 14. Clone clustering was little influenced by the applied procedure so that, adopting the same percentage of divergence, the UPGMA identified two groups less for the coefficient of Sorenso-Nei and Li. The clones evidenced considerable genetic divergence, which is partly associated to the origin of the study material. The clusters formed by the UPGMA clustering algorithm associated to the arithmetic complement of Jaccard were most consistent.

Comportamento fisiológico e morfológico de clones de Eucalyptus urograndis submetidos a diferentes níveis de água no solo

The present study had as its objective the assessment of the possible effects of hydric stress on the growth, physiological characteristics of two different genetic materials from Eucalyptus urograndis. The experiment was carried out in a greenhouse at Faculdade de Ciências Agronômicas of UNESP, campus Botucatu from March to July, 2005. The hydric management was established based on the soil water potential. Two water levels were established, doing the evapotranspired water replacement by pot weighing. Two clones were used, Eucalyptus urograndis 105 and 433, being the first one more resistant to the hydric deficit and the 433 more sensitive to stress. The study was made from a 2×2 factorial (two levels of water × two genetic materials). For the hydric management, the plants were irrigated when they reached a soil water potential of -0.03 MPa or -1.5 MPa. The assessments made were: diffusive water vapor of stomato, transpiration, leaf temperature and leaf water potential. The physiological evaluations throughout the day, in the end of the experiment. Treatments without hydric stress had a higher performance in all studied characteristics, but the clones had no influence. The stomatic resistance followed the potentials, showing higher values in the treatments submitted to hydric deficiency, more intensely for clone 433, being that this also happened with the leaf water potential. The transpiration also followed the leaf water potential and the stomatic resistance more intensely for clone 105 both comparing stressed plants and non-stressed plants. Consequently, the leaf temperatures had higher values for clone 433 on the stressed treatment. Thus, it can be concluded that there was a better performance in plants kept on a soil water potential of -0.03 MPa and a higher resistance to hydric stress for clone 105.

Eficiência de uso de boro no crescimento de clones de eucalipto em vasos

This paper evaluated the critical level, responsivity and boron use effciency on growth and the biomass production in six Eucalyptus grandis x Eucalyptus urophylla clones (Ca, Cb, Cc, Cd, Ce and Cf). An experiment was carried out in pots containing ground silicon, under greenhouse conditions using four boron rates per solution (0; 0.135; 0.27; 0.54 mg L -1 of B). The treatments were combined in a randomized block experimental design in a 4 × 6 factorial scheme with three replications. Plant height, stem diameter, dry matter production in the shoots of the plant and boron use effciency in the leaves, stem and total dry matter at the 8th month of age were evaluated. Due to boron fertilization, growth and shoot biomass were observed in the Eucalyptus plants after 240 days of being planted in pots. The increases in growth and biomass were 35 to 54% and 21 to 64%, respectively. The boron rates that promoted major growth of the plants were 0.33 to 0.44 mg L -1 of B and in this range the most effcient clone for dry matter production of leaves was Cf and the least effcient one to stem biomass production and the shoot biomass was Cd, no signifcant differences among other clones were observed. The critical level of boron in solution was 0.09 to 0.24 mg L -1 of B in the growth of the plants.

Análise de crescimento em clones de eucalipto submetidos a estresse hídrico

The aim of this study was to evaluate Eucaliptus grandis genotypes (Clones 105 and 433) in relation to drought tolerance, through growth plant analysis. Black PVC pots with 10 liter volume were used for cultivate plants in polyethilene greenhouse oriented east/west. Completely randonmized design with four treatments was used: two clones and two minimum soil water potentials (- 0.03 and -1,5 MPa) and sixteen replicates. Pots were weighed daily in order to evaluate water content and characteristic soli water curve was determined. Plant development was obtained each 15 days from planting until 60 days through total dry matter (DM), leaf area index (LAI), leaf area ratio (LAR), net assimilative ratio (NAR), specific leaf area (SLA), relative growth ratio (RGR) and absolute growth ratio (AGR). Results showed that clone 105 presented less sensibility to water deficit, which qualify it as genetic material for use under dry soil conditons. On the other hand, both clones had similar behavior with no water restrictions.

Respostas de clones de Eucalyptus grandis e E. grandis x E. urophylla à supressão de boro

The present work had as objective the study of clones of Eucalyptus grandis and E. grandis × E. urophylla under boron suppression on growth in height and diameter, development of symptoms of deficiency, boron content in leaf and polyols production. Plants were cultivated in pots with quartz in a greenhouse using two levels of boron per solution (0 and 0.5 mg L-1 of B). The 32 treatments followed a factorial scheme: 16 × 2 -16 clones and two doses of boron in a randomized block experimental design, with fve repetitions, totaling 160 plots. Plants were evaluated weekly for deficiency symptoms and monthly for height, stem diameter and leaf content of boron in different plant parts. The content of polyols was measured in two occasions: at 162 days and 192 days after starting the experiment. Decrease of growth and quick development of deficiency symptoms 40 days after boron suppression were observed, as well as a decrease of polyols synthesis. Foliar analysis, with boron supplement, resulted in the presence of mannitol and sorbitol in high enough concentration so that the evaluated plants could be considered rich in those polyols. Under boron suppression, boron levels in different portions of branches and stems of plants, as well as the presence of mannitol and sorbitol, indicated a conditional mobility of boron in Eucalyptus.

Capim-colonião e seus efeitos sobre o crescimento inicial de clones de eucalyptus × urograndis

This study aimed to evaluate the guinea grass effect (Panicum maximum) on the initial growth of different Eucalyptus × urograndis clones. Two assays were established with eucalyptus clones and guinea grass seedlings. The plants were grown in plots with cement borders filled with soil. Each plot received a eucalyptus seedling. The first assay had a completely randomized experimental design, with three replications, and treatments in a 5x2 factorial scheme (five eucalyptus clones and the absence or presence of two guinea grass plants at 10 cm distance from eucalyptus seedling). The second assay was similar to the first, however with three eucalyptus clones. The experimental design was completely randomized, with five replications, and a 3x2 factorial scheme (three eucalyptus clones and the absence or presence of two guinea grass plants). The presence of eucalyptus clones did not affect guinea grass development. The eucalyptus clones that coexisted with guinea grass plants did not show differences in their development, making the clones equal when under competition. The most susceptible characteristics of eucalyptus clones to guinea grass were foliar area, shoot and stem dry matter. Clone 3 showed the most sensitivity to guinea grass, and clone 1 was the most tolerant, but all clones studied suffered a negative interference from guinea grass.

Desenvolvimento inicial de variedades e clones de cana-de- açúcar em Latossolo Vermelho Distrófico, Aparecida do Taboado-MS

In Brazil, as in other sugar cane (Saccharum spp.) producing countries, varieties and clones have been continuously developed and tested in order to obtain varieties better adapted to changes in climate, soils and management, seeking a better performance in soils and climates of low agricultural suitability for the culture. In this study, the initial vegetative growth and performance of five sugar cane clones (CT96-3095, CT95-3079, CT95-1425, CT96-3024, CT92-1882) and two varieties (SP81-3250 and SP91-1049) were evaluated in an environment characterized by soils of low fertility and sandy texture. The experiment was carried out in a randomized design with seven treatments, consisting of the two sugar cane varieties and five clones. The plots contained six 15 meters sugar cane rows with a line spacing of 1.50 m. The average tiller number, tiller leaf area, vegetative cover, shoot biomass and rate of cover between rows of sugarcane were determined through six assessments in the first half of 2008. At the end of the evaluation (116 days after planting) the results showed that the clones (CT96-3095, CT95-3079, CT95-1425, CT96-3024, CT92-1882) were not significantly superior to the two considered varieties (SP81-3250 and SP91-1049).