RCAAP Repository

Pasture arborization with nodulating legumes trees represents the most economic and ecological strategy to add nitrogen to the system plant-soil. However, for introduction of trees in pasture it is necessary to identify grass species that are able to grow under the trees where ligth intensity is lower. The present study was conducted at Embrapa Agrobiologia, Seropédica/RJ, Brazil, to test three grass species (Coast cross 1, Pennisetum purpureum cv. Cameron and Brachiaria brizantha cv. Marandu) and three leveis of shadowing (25, 50 and 75 %). All leveis of shadowing decreased the root biomass of ali the three grass species tested while B. brizantha and P. purpureum showed that their shoot was I ittle affected by shadowing. B. brizantha produced more root biomass than the other two species in ali leveis of ligth intensity tested. 

The adoption of soil tillage systems compatible with the soil, climate characteristics found in southern Brazil is an indispensable procedure for soil amendment and to maintain the commercial fields economically iMe- grated in the agricultura' production system. The effects of soil tillage systems on the yield of white oats (Avena saliva L.) were compared over a eight-year period in a crop rotation of wheat/soybean, commom vetch/corn, and white oats/soybean. Four soil tillage systems were evaluated: 1) no-tillage, 2) minimum tillage, 3) conventional ti Ilage using disk plow plus disk harrow, and 4) conventional tillage using moldboard plow plus disk harrow. An experimental design of blocks at random, with three replications were used. The main field plots (4 x 90 m) were formed by soil management systems, while the subplots (4 x 10 m) consisted of crop systems. The average yield of white oats grown under no-tillage from 1990 to 1997 (2,959 kg/ha) and under minimum tillage (2,938 kg/ha) was higher than the yield obtained for white oats grown under conventional tillage using either disk plow (2,709 kg/ha) or moldboard plows (2,682 kg/ha). Higher contents of soil organic matter, extractable P, and exchangeable K were ohserved in the 0-5 cm layer for the conservation tillage systems (minimum tillage and no-tillage), as compared to the conventional tillage systems (disk plow and moldboard plow). The no-tillage and minimum tillage system should be preferred for white oats cropping.

Genetic dissimilarity measures are commonly used by plant breeders to identify dissimilar parents to get desired segregant populations. Multivariate techniques were utilized to evaluate the genetic dissimilarity among 53 genotypes of the carioca bean (Phaseolus vulgaris L.). Six traits were evaluated in a field experiment using a randomized block design with four replications. Canonical variable analysis and cluster analysis using Tocher's agglomerative method and hierarchical method (nearest neighbor) were applied. Generalized Mahalanobis distance (D2) was used to measure dissimilarity. Genotypes comprised twenty six distinct groups by Tocher's method. Thousand seed weight was the most important trait to the total genetic dissimilarity. The obtained results allowed to characterize dissimilar genotypes to be strategically used in artificial hybridizations.

With the objective to anticipate the harvest period and to enhance fruit size in peach c v. Diamante, in the two auxins: acid (3.5.6-TPA) and 2,4-diclorofenoxipropionic acid (2.4—DP), a citocinine (pheni I urea) and girdling of the main branches werc applied on trees located in the Depressão Central of Rio Grande do Sul, at the Estação Experimental of the Federal University of Rio Grande do Sul, in Eldorado do Sul, latitude 30°39'S and longitude of 5I °06'W. The following treatments were applied at phase II of fruit development, in a randomized block design: 1) 10 ppm 3,5,6 TPA; 2)20 ppm 3.5,6 TPA; 3) 10 ppm 3.5,6 TPA plus girdling of branches; 4) 20 ppm 3,5,6 TPA plus girdl ing of branches; 5)25 ppm 2,4 -DP; 6)50 pppm 2,4-DP; 7)25 ppm 2.4-DP plus girdling of branches; 8)50 ppm 2,4-DP plus girdling of branches; 9) 10 ppm pheni turca (CPPU); 10) girdling of branches; and II) control. ALI the chemicals were applied directly to the fruits, spending about 1,25 lítree. Fruit diameter, of 10 fruits per troe, was measured weekly, from thinning to harvest. The number of fruits and total prodution per tree was determined. The percentage from the total number of fruits at each harvest was determined at the end of the harvesting period. Aux i n treatments and girdling of branches did not increase total number of fruits/tree and did not increase average fruit weight. However, auxin treatment, specially 20 ppm 3,5,6- TPA with or without girdling of branches, resulted in anticipation of about 15 days in begining of harvest. Fruit quality was not affected by any of the treatments.

Coccoidea is a homogeneous group of insects commonly called scales. They are highly specialized plant parasites and can cause serious damage to agricultural economy by their potential pest condition. The classification of this group is based almost exclusively on morphological characteristics of the adult female. The aim of this work was to update the species records of the Coccoidea Colletion of Prof. Ramiro Gomes Costa Museum. There are 88 species distributed in 8 families of which 16 are type-material, 7 new records for Rio Grande do Sul and one for Brazil.

Genotype x environment interaction analysis was performed on grain yield of twenty-two commonbean (Phaseolus vulgaris L.) genotypes grown at tive different locations in Rio Grande do Sul, during two growing

Genotype x environment interaction was perfomed on grain yield of twenty-two genotypes of common bean (Phaseolus vulgaris L.) grown at tive different locations in Rio Grande do Sul, during two years. The stability parameters were estimated by linear regression model of EBERHART and RUSSEL (1966). In addition, the environmental index of the model was obtained by weather variables and disease index. The best estimator of the environment was the normal environmental index, whereas the weather variables and disease index failled to provide a good estimation.

In the State of Rio Grande do Sul, the losses of spring-summer crops by drought events has showed the necessity of specific studies about local water deficit regarding the irrigation practice. Depressão Central lowlands, specifically the Arroio dos Ratos soil, are usefitl alternative to wet rice and are suitable for irrigation. So, the water deficit occurrence in the spring-summer period in Eldorado do Sul, with Arroio dos Ratos soil, were studied, adopting a soil water-storage capacity of 67.71 mm. The homogeneous serial dates of the 1967-1993 period were used to evaluate the referential evapotranspiration, and to compute the average water balance and the serial water balance for ten-day periods. The deficit and water indexes frequency were calculated. The results showed that water deficit occurs from November through March, however December, January and February were the months with the most frequent and severe water deficit. 

The main objective of the experimenta carried out in August 12, 1993 and in October 6, 1995 at the Estação de Pesquisa e Produção de Viamão, Rio Grande do Sul, Southern Brazil was to compare the effect of organic manure on yield and quality of carrot cultivars. In the first experiment the cultivars Nantes Forto, Flakkese, Fuyumaki, Nantes Superior and Harumaki Kinko were evaluated. In 1995 `Nantes Superior' and `Harumaki Kinko' were replaced by 'Brasília' and `Tin Ton'. For the manuring treatments, chicken and quail manure were used in two leveis. In the first experiment results showed a h igher yield for Nantes Forto' for the commercial roots. The materiais differed in number of roots, weight, diameter and lenght. In the second experiment, results did not show significant differences among cultivars. However, there were differences in the average weight (better with 'Brasília') and in average length (better with `Tin Ton'). In 1 993. organic manure provided an increase in ali the factors evaluated, except in the number of roots. In the second one, the organic manure provided an increase in average root weight, average root diameter and average root length.

The fluctuation of the citrus flat mitc Brevipalpus phoenicis (Geijskes, 1939) Sayed, 1946 (Acari, Tenuipalpidae) population was surveyed in Taquari, Rio Grande do Sul, froni December 1996 to October 1997. This study was carried out in a 'Valência' orange orchard. The experimental design was arranged in a randomized complete block with four replications. Plants were divided in quadrants, and the samplings were taken in three fruits per quadrant, in five points of the fruit (one at style end and four in arcas with citrus scab lesions). Results showed significant difference in the occurrence of the citrus flat mire. Relative humidity and rainfall significantly affect the occurrence of the citrus flat mite.

The choice of an adequate soil management system and planting techniques increases pineapple yield and lowers the production costs as well. To estimate the effect of different soil management systems (conventional tillage, strip-tillage and no-tillage), and two planting techniques (furrow and spear) on productivity, fruit characteristics, percentage of sprouting, and seedling production, a field experiment was carried out from August/1997 to January/1999 at the Estação de Pesquisa e Produção of FEPAGRO, Maquiné, Rio Grande do Sul, Brazil. The soil type was a clay loam Argiudoll. Results showed that productivity and harvest percentage were higher in conventional tillage (1 1.94 ilha and 52%) than in no-tillage (5.67 t/ha and 27.7%). The productivity and harvest percentage in furrow and spear plantings did not differ statistically. Fruit diameter and length, crown size, brix degree, number and average weight of sprouts were not affected by the different treatmcnts. 

The estimate of pineapple profit (total income/costs) helps the producer to better plan the crop. An experiment was established with pineapple 'Perola', grown in Rio Grande do Sul, under high, medium, and low levels of technology, using three population densities (50 000, 40 000, and 30 000 plants/ha), with a total of 40 000, 30 000, and 21 000 fruits sold, respectively. The fruits were classified according to their weight (<0.6 kg; 0.6-0.8 kg; 0.8-1 kg; > 1 kg), and price (R$ 0.35; R$ 0.45; R$ 0.55; R$ 0.65). The income was estimated considering the total number of fruits in each class and the price per unit. To estimate production costs, the following expenses were considered: mechanical operations, manual operations, inputs, materiais and equipments, leasing, interests, and devaluation of the equipments. The cost comprised the average princes of the local market in August 1999, and the fruit price was the average paid to the growers in 1997, 1998, and 1999.The total income from fruit safe was R$ 23,200.00, R$ 15,000.00, and R$ 8,820.00, for an estimated production cost of RS 10,061.16, R$ 8,181.80, and R$ 5,999.77, with a net income of R$13,139.00, R$6,618.00 and R$2,820.00 (US$1.00 = R$1.88 in 08/16/99), resulting in retum taxes around 130%, 83%, and 47% for the respectivo technological leveis: high, medium and low. Under the medium technology, the seedlings, interests, manual operations, fertilizers, materiais and equipments, herbicides, leasing, devaluation, mechanical operations, inductors and surfactante, as well as insecticides had the following percentages of the total cost of the crop, in this order: 41, 18, 13, 8, 5, 5, 4, 2, 2, I and I. Regardless of the risk and the high costs, pineapple culture may have a high profit when cultivated under a high technological level.

Adequate soil management may increase its permeability and water storage and allow to estimate the irrigation requirements for growing pineapple in the northeastern coast of Rio Grande do Sul state, Brazil. Evapotranspiration data of the period 1980-1990, as wel I as temperatures from 1956 to 1999, and rainfall from 1931 to 1960, for this region, were compared with the conditions when irrigation is indicated. At Estação de Pesquisa e Produção of FEPAGRO, in Maquiné - RS, was conducted an assay to study the effects of soil management (conventional tillage, strip-tillage and no-tillage), in the main plots, and planting techniques (furrow and spear), in the subplots, on the soil gravimetric moisture. Soil management and planting techniques did not affect the gravimetric moisture. In Maquiné the average rainfall is 1,650 mm/year, above the required for pineapple (1,000 to 1,500/year). The analysis of evapotranspiration, and temperature data collected at the experiment station indicates no need of irrigation for pineapple culture in this region. Therefore, during the period of intensive growth, when water needs increases, and under conditions of low rainfall, such as the period of November-December, and April-May, irrigation might be necessary.

Low water availability is a limiting factor for growth and development of summer crops in Rio Grande do Sul State. Brazil. Studies aiming to determine crop coefficients for water requirements are important for water supply recommendation. The objective o f this study was to determine the maximum evapotranspiration of sunflower (ETm) in relation to the reference evapotranspiration (ETo) and with solar radiation (Rs), to obtain the ratios ETm/ ETo (Kc , coefficient) and ETm/Rs (Kc 2 coefficient), at different crop stages. Field experiments were carried out at Centro de Pesquisa de Fruticultura, in Taquari, 29°48'S latitude, 51°49'W longitude and 76 m of altitude, during 1987/ 88, 1989/90, 1990/91 and 1991/92 crop seasons. The average ratio ETm/ETo for the whole crop cycle (from sowing to physiological maturity) was 0.77, while the average ratio ETm/Rs was 0.48 for the same period. The highest average values of crop coefficients occurred during flowering period with average values of 1.12 and 0.71, respectively, for Kc, and Kc 2 .

An experiment was conducted in Porto Velho, Rondônia, for pasture deferment and utilization of the forage accumulated of with the purpose to determine the best time Panicum maximum cv. Tobiatã for herd supplementation during the dry season. The experimental design was a randomized complete-block (split-plot) with three replications. The periods of deferment began on February 28, March 28 and April 28 and constituted the main plots, and the months of utilization (June 30, July 30, August 30 and September 30) the sub-plots. Results indicate the feasibility of stockpiling the grass during the rainy season, to provide forage for herd supplementation in the dry season. For utilization in June or July, the herbage deferred in February provided higher dry green matter (DGM) yield, while for utilization in August or September, the herbage stockpiled in March was the most productive. The grass, irrespective of deferment dates, showed significant reductions (1 3 <0.05) in crude protein (CP) content and in vitro DOM digestibility (I VDGMD) towards the later utilization date. However, the highest CP yields were obtained in herbage stockpiled in March and used in July or August. Deferment starting in March or April and to be used in June produced forage with higher IVDGMD coeficient. In order to obtain higher forage yields with better quality, it is suggested to start deferment in February for pasture utilization in June or July, and in March for pasture utilization in August or September.

To evaluate the effect of chemical and biological insecticides on predators and parasitoids of soybeanpests, an experiment with randomized block design , with plots measuring 100 x 100 m replicated three times, was setup. The treatments were applied two times on each plot, the first for controlling the velvetbean caterpillar (Anticarsiagemmatalis), and the second for stink bugs (Nezara viridula, Piezodorus guildinii and Euschistus heros) control.The treatments consisted of the insecticides and doses (g a.i./ha) applied two times: 1. endosulfan (210/525); 2.lambda-cyhalothrin; (4.5/9); 3. monocrotophos (96/180); 4. Baculovirus anticarsia (24 g formulated)/monocrotophos(120) + NaC1(0.5%). The shock method was used to sample the arthropod population, by applying a broad spectruminsecticide (dichlorvos) over the sampling area, collecting the dead insects on plastics placed on the round andtransferring them to the laboratory to be identified and counted. All insecticide treatments reduced the number ofpredators two days after being applied to control stink bugs, but only lambda-cyhalothrin showed a lower populationthan the check, 26 days after the first application. The determination index of parasitoid versus total dipteranspopulation was r2=0.99, meaning that the insecticide effect over the total dipterans and the population of parasitoidsof this orders was the same. The parasitoids populations and the index of parasitism of pests were not affected by thetreatments.

Coriander is an aromatic and medicinal plant of great importante. The grains and leaves are marketed, used in pharmaceutical industry, and as seasoning. The aim of this work was to identify differences among cultivars and sowing periods. The experiments were carried out in Passo Fundo, Rio Grande do Sul. The seeds of the cultivars Verdão, Português and Nacional Palmeira were submitted to the germination standard test. In the evaluation of the sowing periods, the treatments were arranged in a factorial 3 x 2 (cultivars x sowing periods, April and August). A randomized complete-block design, white Eive replications was used. The seeds presented low gennination (19-40%). 'Nacional Palmeira' had early flowering. The best sowing date was in autumn. 'Verdão' presented higher yield in the two sowing dates, and the cultivar Português, with two cuttings, provided the highest number of marketable bunches.

To verify the genotype x environment interactions, a study was undertaken using the yields from the bean varieties and breeding times state Trials, carried out during five years in seven environments. throughout the state of santa Catarina. Statistical analysis were performed using the main recommended varieties which participated in ali trials from 1991 to 1995, taking the grain yield as an indicator of adaptability. The trials were planted with four replications in a randomized complete block design, with four-row plots, 5 m long. The significance of the genotype x environment interaction indicates that the varieties/lines did not have the same behavior across the environments. The value of the estimated environment x genotype interaction variance (a 2c,$) was higher than year x genotype interaction (a 2cxyw), indicating that the best strategy is to use a higher number of locais rather than years to evaluate bean genotypes. The cultivars with better yields along this period were Macanudo', `Barriga Verde' and `Carioca'.

To study alternatives in chemical control for the leaf cutting ant, Acromyrmex striatus (Roger, 1863), three field assays were conducted in 1997 and 1998 with powdered formicidae in Santa Maria, Rio Grande do Sul. Dosages and application methods were tested in the first assay, and dosages and commercial formulations were studied in other two experimenta. The effect of dosages, application methods and products were evaluated two and three times after application. Doses and application methods on the first assay were not efficient to control this ant species. Chlorpyrifos (20g a.i./kg), Fenthion (50g a.i./kg) and Deltamethrin (2g a.i./kg), beginning at 5 g per hill entrance of the commercial product, were effective in controlling this species. However, Diazinon (10g a.i./kg) rapidly inactivated the ant hills but did not eliminate, definitively, the nests of A. striatus.

Bean anthracnose and common bacterial blight caused by Colletotrichum lindemuthianum•andXanthomonas axonopodis pv. phaseoli, respectively, may cause considerable yield reduction of common bean inBrazil. Genetic resistance is onc of the componente of the integrated disease control of common bean. In addition,lodging and pod height are importam characteristics that should be consideréd during the development of a newcultivar. The objective of this study was to develop common black bean tines resistant to four important C.findem/d//anum pathotypes and to X axonopodis pv. phaseoli with highly desirable agronomic characteristics andhigh yield potential. Crosses were designed to combine such characteristics into a single line. Eight lines wereobtained combining resistance and desirable agronomic characteristics. The line 9310639 showcd a high diseaseresistance to anthracnose and bacterial blight and is a valuabl e source of resistance for common bean improvement.