João Baptista da Silva

Divergência genética entre cultivares locais e cultivares melhoradas de feijão

A grande variabilidade genetica presente no germoplasma de feijao (Phaseolus vulgaris L.) em uso na agricultura familiar no Brasil tem sido plenamente reconhecida. A eficiencia da conservacao e o aproveitamento desta variabilidade aumentam quando esta e devidamente caracterizada. O objetivo deste trabalho foi caracterizar a variabilidade genetica de parte do germoplasma existente em poder de produtores de feijao no Rio Grande do Sul, e de cultivares produzidas pela pesquisa, e reuni-las em grupos de similaridade genetica. Foi avaliada a divergencia genetica de 37 cultivares locais (land races) e 14 cultivares indicadas pela pesquisa no Estado, utilizando 40 descritores morfologicos; a grande maioria desses descritores sao necessarios a protecao legal. Empregou-se analise multivariada, por intermedio de componentes principais e metodo de agrupamento. O uso destas tecnicas possibilitou identificar descritores ineficientes ou redundantes no estudo da variabilidade genetica e reunir as cultivares estudadas em quatro grupos distintos de similaridade genetica. As cultivares locais revelaram variabilidade superior a encontrada nas cultivares oriundas da pesquisa, o que sugere a importância da sua inclusao em programas de melhoramento.

Avaliação de populações de Butia capitata de Santa Vitória do Palmar

ABSTRACT - The genus Butia belongs to the Arecaceae family and shows five species occurring in the state of Rio Grande de Sul. The specie Butia capitata requires special attention, not just for its use as fresh consumption but also as processed product. However, even having its use recorded since the pre-historic period this specie has been explored only in an extrativist way as most species of native fruits. Moreover, the specie is seriously committed in the short term by the absence of natural regeneration and a very high risk of extinction in the future. Therefore, the objective of this work was to compare the fruits, from chemical and physical parameters, and as well as to observe the productive data of the trees of three different popula-tions of pindo palm tree in Santa Vitoria do Palmar. The data were obtained in experiments carried out in the 2005/2006 and 2006/2007 seasons at three sites located in Santa Vitoria do Palmar. The results allowed verifying that the populations of Butia capitata assessed in Santa Vitoria do Palmar showed variability for length of cycle, fruit epidermis color, juice volume, relationship between total soluble solids and total titrat-able acidity, biometric characteristics of fruit and yield. The population denominated Celina showed the highest yield and industrial income. Celina and Sao Jose showed the best biometric characteristics of fruit. The population Aguiar had the better relationship between total soluble solids and total titratable acidity.Index terms: Pindo palm tree, yield, fruit quality.

ENRAIZAMENTO DE MINIESTACAS DE AMEIXEIRA

The trial aimed to maximized the yield of the number of plum cuttings per branch. Growing shoots of two plum cultivars (Reubennel and Pluma 7) were used. The apical portion with diameter shorter than 2 mm was eliminated. The mini-cuttings were obtained by making a 0.5 cm cut above the bud and another one next to the subsequent bud. The mini-cuttings were immersed in a solution of IBA 2000 mg.L-1 for five seconds. As control, a solution composed of distilled water mixed with the same volume of methyl alcohol was used to dissolve the IBA solution. The mini-cuttings were placed to root in an expanded polyesterene tray containing a mixture of rice husk ash and vermiculite (2:1 v/v) as substrate. Half of this material was covered with (20 micra) thick transparent plastic and the other part without it. The experiment was carried out in a complete randomized block by using a factorial 2x2x2 (cultivar, IBA and plastic film) with four replications and fifteen mini-cuttings per plot. After 39 days the percentage of rooting, root number and length were evaluated. Pluma 7 cultivar showed the highest rooting potential and the highest sensibility to IBA. One - bud cuttings are able to form root. It is possible to obtain rooted cuttings with the whole shoot when they are treated with IBA. It was observed that plastic film reduced the root cutting . IBA increases the rooting, the number and root length of the studied cultivars.

Efeito da aplicação de baixa temperatura em plantas de macieira sobre o crescimento durante a aclimatização

The present work aimed to evaluate the growth of shoots of a rootstock of the plant growth of the apple (Malus prunifolia Borkh, cv.Marubakaido) tree during the acclimatization process. After two weeks of acclimatization, the plantlets were transferred to a growth room and kept under temperature of 4±1oC, 16-hour photoperiod at 5µEm-2s-1 of radiation for 0, 240, 480, 720, 960, 1,200 and 1,440 hours. So, the plantlets were transferred to the greenhouse where their growth was evaluated every two weeks during 90 days. Internode length, bud number and dry matter weight of aerial part and roots were also evaluated at the end of the experiment. The percentage of plant survival was evaluated after a month in greenhouse. An increase was verified in the plant height and internode length proportional to the time kept under low temperature. Chill did not affect the plant survival, the bud number and the dry weight of aerial part, but it did affect the root dry weight.

Nutrientes na água para irrigação de arroz na Região Sul do Rio Grande do Sul, Brasil

The flooded rice crop presents low response to fertilization when compared to dry land crops, cultivated in soils with same characteristics of fertility. This is caused, in part, by physical and chemical changes that take place in the soil due to flooding, increasing nutrients availability. Another factor that also can cause the low response of rice crops to fertilization is nutrients supply through the water used in the irrigation. This paper was aimed at quantifing nutrients concentration in the irrigation waters used in the Southern region of the State of Rio Grande do Sul, Brazil, as well as estimating its possible contribution to rice plant nutrition. Sixty samples of waters were collected from dams, lagoons and rivers, twenty in each source. It was determined N-ammonium, N-nitrate, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), zinc (Zn), iron (Fe), manganese (Mn), silicon (Si) content, pH and electrical conductivity (CE). The elements concentration in the irrigation waters decreased in the following order Na > Ca > Si > Fe > Mg > K> Mn > N> Zn >P. The average elements contents were different between irrigation sources: N and Si content in rivers were higher than those in the lagoons; Ca and Mg were more concentrated in lagoons than in dams; Fe was more concentrated in dams and rivers compared to the lagoons. The estimated nutrient contribution by irrigation waters can correspond to all of the calcium, iron, silicon and sodium, and up to 28% of magnesium and 12% of potassium uptake, in average, by rice plants.

Estabelecimento e multiplicação in vitro de Prunus sp. em diferentes meios de cultivo

The work was performed aiming to evaluate different media for the establishment and in vitro multiplication of some rootstocks species of Prunus. Microcutings of 1,0cm long were incubated under 20 mE.m-2.s-1 radiation provided by white fluorescent lamps, 16-hour photoperiod and temperature of 25±2oC. The establishment media used were as follow: MS, ¾ MS, SH and Villegas, and the multiplication media used were: SH and ¾ MS. The ¾ MS medium was also tested with different agar concentrations (4.5; 5.5; 6.5 g.L-1). The percentage of establishment, contamination, oxidation and growing of the explants were evaluated. The Villegas medium provided low oxidation during the period of in vitro establishment. The ¾ MS medium provided higher percentage of establishment of explants. In the multiplication phase, the highest growth percentage, multiplication rate and bud number, were found in ¾ MS medium with 5.5 g.L-1 agar.

Inventário da família Orchidaceae na Amazônia Brasileira: parte I

A total of 378 species of 99 genera were registered, some of these species are new to science while and others are new records for the Brazilian flora.

Efeito da amonização com uréia sobre os parâmetros de qualidade do feno do capim-Annoni 2 (Eragrostis plana Nees)

This study aimed to evaluate the ammoniation effect on the crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HEM), cellulose (CEL) and lignin (LIG) levels and the in vitro organic matter digestibility (IVOMD) coefficient of urea-ammonia treated (4%; dry matter basis) Annonigrass 2 (Eragrostis plana Nees) hay, at five cutting ages (30, 60, 90, 120, 150 days). A randomized complete block design was used, with four replicates in a factorial arrangement (2x5), with two factors: hay treatments (2) and cutting ages (5). The comparison among hay groups (ammoniated or not) showed a highly significant increase on the CP contents of ammoniated hay. On the other hand, FDA and CEL fraction significantly decreased as a function of urea-ammonia treatment. No differences were found for NDF, HEM, LIG contents and the IVOMD coefficients among hay groups. It was concluded that: 1. ammoniation does not affect NDF, HEM, LIG levels and IVOMD coefficients; 2. urea-ammonia treatment of Annonigrass 2 hay promotes an increase on the CP contents and a decrease on the ADF and CEL contents of this grass; 3. Annonigrass 2 hay is feasible up to 90 days of growth without prejudice to the quality parameters, since urea-ammonia is treated.

Estimativa da produtividade de arroz irrigado em função da radiação solar global e da temperatura mínima do ar

Considering the importance of irrigated rice production in the State of Rio Grande do Sul and that its performance is influenced by the weather conditions, the objective of this study was to estimate the grain yield of this crop as a function of global solar radiation and minimum air temperature using procedures of linear simple and multiple regression. A field experiment was conducted at the district of Capao do Leao, State of Rio Grande do Sul, Brazil, during three growing seasons. Six sowing dates and eight cultivars of distinct groups of cycle lengths were used in each crop season. Ten main culms of each cultivar were marked to determine the main stages of development. The dependent variable (Y) was the average grain yield of four repetitions of each sowing date and the independent variables were: the average of global solar radiation (X1), the average minimum air temperature (X2) and the average of squared minimum air temperature (X3), computed for four periods of plant development for global solar radiation and for three periods for minimum air temperature. Most of the variables, when tested isolately, presented a significant linear relationship with grain yield, but the coefficients of determination (r2) were higher in multiple linear regressions involving the main variables. Regression models that use global solar radiation and minimum air temperature in distinct physiological periods of plant development as predicting variables, are suitable for estimating grain yields of irrigated rice.

Estádio da meiose do micrósporo como marcador do final da endodormência em pessegueiro

O objetivo deste trabalho foi testar a validade da tecnica da meiose polinica como marcador do final da endodormencia em pessegueiro, em condicoes de inverno subtropical. Determinou-se o numero de unidades de calor (GDHoC - Growing Degree Hour Celsius) acumulado desde 1o de maio ate o final da meiose e desta ate 10 e 50 % de florescimento. Foram efetuadas correlacoes entre tetrades + polen versus GDHoC e tetrades + polen versus numero de horas de frio (temperaturas do ar £ 7,2 oC), nas diferentes datas de observacao compreendidas entre 1o de maio e final da meiose. Pelos resultados dos dois anos de observacao, verificou-se que ha necessidade de calor para que as celulas-mae de polen atinjam o estadio de tetrades. O metodo da meiose polinica mostrou-se inadequado como marcador do final da endodormencia em pessegueiro.