RCAAP Repository

Ten oat genotypes (Avena saliva L.) and twelve environments were tested to evaluate adaptability andstability of grain yield, to discriminate genotypes on different environments to utilize in plant breeding programs. Thebissegmented linear regression was adopted as statistical method. The analysis showed not only that genotype xenvironment interaction was significative, as well that the environment variation contributed with larger portion than thevariability among genotypes for the significance of this interaction. The results showed that the behavior of the analyzedgenotypes was differentiated for the different environments, accepting existence of genetic variability among the testedgenotypes. Except for UFRGS 7, alI the other genotypes expressed grain yield instability.

To evaluate the effect of soil tillage systems and crop rotation on com yield an experiment was set up in Passo Fundo, RS, .13razi1, which was monitored over a four-year period. Fiou soil tillage systems — I) no-tillage. during winter and summer seasons, 2) conventional tillage using disk plow and disk harrow, in winter and no-tillage, in summer, 3) conventional tillage using moldboard plow and disk harrow, in winter and no-tillage, in summer, and 4) mini muni tillage, in winter and no-til lage, in summer. — and two crop rotation systems ¡system 1 (wheat/soybean and common vetch/corn) and system II (wheat/soybean, black oats or white oats/soybean, and common vetch/corn)] were compared. An experimental design of blocks at random, with split-plots and three replications, was used. The main plot was formed by soi I tillage systems, while the split-plots consisted of crop rotation systems. The yield of com grown tender to-tillage and minimum tillage was higher than the yield obtained for com grown after conventional tillage using disk or moldboard plow and disk harrow. There were no significant &Tem of crop rotation systems on com yields.

During four years, in Passo Fundo, RS, Brazil, the effects of soil management and crop rotation systems were assessed. Four soil management systems — 1) no-tillage, 2) minimum tillage, 3) conventional tillage using a disk plow, and 4) conventional tillage using a moldboard plow—and three crop rotation systems [system I (wheat/soybean), system II (wheat/soybean and common vetch/sorghum or corn), and system I II (wheat/soybean, common vetch/sorghum or com and wh i te oats/soybean)I were compared. An experimental design of blocks at random with split-plots and three replications was used. The main plot was formed by the soil management systems, while the split-plots consisted of the crop rotation systems. Economic analysis from 1994 to 1997 is presented in this papei. No,til lage (R$ 412.49) and minimum tillage (R$ 389.37) presented higher net returns, while conventional tillage using a disk plow remained in intermediate position (R$ 339.90) and tillage using a moldboard plow showed the lowest net return (R$ 322,18). No significam differences were observed for net return as a result of crop rotation systems. 

Plant arrangement that allow better plant distribuition in the area improve plant growth, resulting in larger grain yield. The experiment was performed at the Agronomic Experimental Station of the Universidade Federal do Rio Grande do Sul, in Eldorado do Sul, Rio Grande do Sul, Brazil, in the 2000/01 growing season. The objectives were to evaluate the soybean growth by canopy stratum in response to plant arrangemnt and the effect in grain yield. The cultivar tested was 'BRS 137', in no-till planting. The treatments were arranged in a split-splitplot randomized complete-block design, with four replications. Water availability (with and without irrigation), row spacing (20 and 40 cm) and population leveis (20, 30 and 40 plants/m 2) were tested. Growth atributes (leaf area index and dry matter), grain yield, by soybean canopy stratum, were determined in samples of ten plants, in sequence in the row, in each sub-subplot. Grain yield was incresead by irrigation and was detected interaction between row spacing and plant population. The plant arrangement of 20 cm row spacing and population of 20 plants/m 2 resulted in greater grain yield. There was a linear decrease in grain yield with the increase in population, with row spacing (20 cm) reduction. The same was also noticed at the medium and botom canopy stratum. These results were consequence of the higher leaf area index and dry matter obtained in the soybean vegetative period, mainly in the medium and botom canopy stratum. 

 In this paper it is presented for the first time the meiotic behavior of microsporogenesis data concerning to fourteen populations of three species of Macroptilium (Benth.) Urban native in the south of Brazil (Rio Grande do Sul). The association and distribution of chromosomes was considered normal in both meiosis 1 and 11. The normal ity for meiotic cells was kept above 91% with exception of M. erytholoma (Benth.) Urban Cacequi population. The meiotic indexes (MI) were kept above 90% with the exceptions of M. heterophyllum(Willd) Maréchal et Baudet from Alegrete and M. herythroloma from Santa Maria populations. The si gnifi cat ve differences among the populations i ns ide each species and between the species shown lhe characteristic genetic variability that each plant has and use to adapt itself to the environment and promote the continuity of the generations. The data obtained shown that the plants were normal regarding to the meiosis and potentially fertile without problems in the inclusion of the species in programs of selection, crossing and viable seed production.

Utilization of red rice as forage plants constitute a control method of this weed along with a gain in animal products. An experiment was carried out at Estação Experimental de Terras Baixas/EMBRAPA CLIMA TEMPERADO, Capão do Leão, RS ,I3razil, to evaluate under, hydromorphic soil conditions, forage production, crude protein and "ia sita" digestibility of dry matter of red rice (Oryza saúva L.). In a split plot complete randomized block design, with four replications. The following variables were compared: a) Five seed densities in the soil (50, 150, 250,350 and 450 seeds/m 2); b) Two cutting times (vegetative and flowering) and c) Two red rice biotypes (straw hull and black hull). Higher forage production was obtained with one cutting in the flowering stage. The density of seeds in the soil influenced maximum forage production. Higher crude protein and "ia sita" digestibility was obtained with cuttings in the vegetative stage.

This study aims to understand the rationality that orients a large part of familial producers, who are involved in the production of milk, that adopt Mis technological standard in their production systems. A mathematical programming model was devised for feeding systems considering forages with low, medium and high contents of energy and protein. It was verified that the milk production which optimize the economic results for the farmers vary from 10 to 15 liters of milk per cow/day. h was observed that the milk production obtained by the optimization of the feeding systems was always lower that 18 liters per cow/day:Based on the simulations that were carried out, it can be concluded that the adoption of less intensive technological standards is more the result of a deliberate economic rationality of the farmers Man an eventual posture against the adoption of technical progress.

This paper reports the first isolation in Brazil of Escherichia coli in broi ler chickens with lesion of cellulitis. In addition, histopathological examination of the skin to characterize the lesion was also carried out. No significant changes occurred on the epidermis .However,the dermis was infiltrated by lymphocytes,macrophages,eosinophi Is and heterophils. 

Com is the main cereal used in Brazil for pigs and poultry feeding. Its price variation in the last years has led to contemplate the use of other alternatives to its substitution. There is little information in Brazil regarding technical and economic viability of winter cereais use as an alternative feeding for animais. Therefore, knowledge of the chemical composition is of paramount importance in the feeding.formulation for different animal.species. This study aimed to verify the chemical composition of the grains of the main winter cereais produced in the country (white oats, black oats, rye, barley, triticale and wheat). Winter cereal grain samples of a field trial planted in Embrapa Trigo, Passo Fundo, RS, under a randomized block design with three replications were analysed in Embrapa Suínos e Aves, Concórdia, SC, relatively to dry matter, crude.protein, fat, crude fibre, ash, non-nitrogenous substancesand crude energy. The results obtained with the different w inter cereais were advantageous comparatively to corn in animal feeding formulation, suggesting that they show potentiality to be used as a viable alternative. 

The objective of this study was to obtain models to estimate the leaf area of cucumberthrough linear measurements of its leaves. Also, existent models in literature obtained from other placeswere evaluated. The study was carried out during the fali and spring of 2000. The hybrid "Marinda" wasgrown inside a plastic greenhouse in the spacing of 25x 100cm, with plants in a single stem sustained bya plastic thread. The maxim width (L) and the length (C) of leaves were measured, and the leaf area(AF) was determined through the disks method. The models with determination coefficient (R') above0.980 were obtained by the regression analysis. Only some of the existent models in literature showedan acceptable performance. The conclusion was that the leaf area of cucumber may be estimated fromleaf length only.

This work was carried out during the growing season of 1993/94. ft aimed to assess the total extraction of nutrientes and consequently obtain useful information for fertization prescription. Twelve representative of Cabemet Sauvignow( Viris vinifera L.) vineyards in the Serra Gaúcha region in Rio Grande do Sul, Brazil were chosen. Leaves, clusters and branches were picked, counted, weighed and dried, thus supplying dry matter. This material was analysed and its contents in chemical elements were determined. The total extraction of nutrients was the following in decreasing order: K>N>Ca>Mg>P>S>Cu>Mn>Fe>Zn>B. With regard to the parts of the plant, the total extraction obeyed this decreasing order: blade>berry>branch>petiole>angace. The leaf blade extracted all nutrientes in major quantities, except for K, which the berry extracted most. 

Nutritional status of Cabernet Sauvignon vineyards in the Serra Gaúcha region was evaluated, according to the methods developed in Califomia, Michigan and South Africa. The Californian method, using leaf petiole sampled at flowering, identified no nutritional troubles for P, K, Mg, Mn and Zn, but B was deficient in 83.3% of the vineyards. The Michigan method, using leaf petiole sampled during "véraison", identified no nutritional troubles in the vineyards for B, Fe and Mn. For N, 58.3% were below normal nutritional class, and the others were normal; for P 25.0% were normal and 41.7% above normal; K was excessive in 58.3% and above normal in 25.0%; Ca and Mg were normal or in excess for all vineyards; Zn above normal in 75.0%. For the South African method P and B were normal in all vineyards; N in 83.3%; K, Ca, Mg, and Mn were above normal in 91.7% of the vineyards, and Zn in 75.0%. Differences found among methods were probably dueto the phoenological state when samples were taken and tissue analysed.

The importance of this research work results from the fact that relatively few studies on crop rotation systems involving com crop are avalilable. In a trial conducted from 1987/88 to 1995/96, in Passo Fundo, RS, Brazil, the yields of com and sorghum grown in different crop rotation systems were studied. The following systems were evaluated: system I (wheat/soybean or wheat/soybean and common vetch/com or sorghum); system II (wheat/soybean, black oats or white oats/soybean, and common vetch/com or sorghum); system III (wheat/soybean, white oats/soybean, flax/soybean, and common vetch/com or wheat/soybean, sunflower or black oats/soybean, white oats/soybean, and common vetch/com or sorghum); system IV (wheat/ soybean, wheat/soybean, black oats or white oats/soybean, and common vetch/com or sorghum); and system V (wheat/soybean, wheat/soybean, white oats/soybean, flax/soybean, and common vetch/corn or wheat/ soybean, wheat/soybean, sunflower or black oats/soybean, white oats/soybean, and common vetch/corn or sorghum). An experimental design of randomized blocks with three replications and plots measuring 30 m 2 was used. The means obtained from 1987/88 to 1989/90 for systems III (7,547 kg ha') and V (7,739 kg ha -') showed higher yields of com, as compared to systems II (6,923 kg ha') and IV (6,890 kg ha'). The means from 1991/92 to 1992/93 and from 1994/95 to 1995/96 showed no significant differences between com and sorghum yields in the systems under study. Com and sorghum may be grown in crop rotation with common vetch, wheat, soybean, and white oats without negative impact on grain yield. 

Trials were conducted in field conditions in Passo Fundo (1984/89) and in Coxilha (1996/97), RS, and in Guarapuava (1984/90 e 1990/94), PR, Brazil, to study the effects of winter crop residues on soybean grown in succession, under no-till system. Winter crops were white oats knife rolled for mulching purposes, white oats, barley, rapeseed, flax, and wheat for grain yield. In these cropping systems, soybean was grown in the summer in monoculture and in rotation with com and pearl millet. A randomized complete block design with four replications was uséd. Soybean grown after flax and rape showed lower yields and lower plant heights than soybean after barley and wheat. Yields of soybean grown in monoculture were in intermediate position, between yields of soybean grown in crop rotation and soybean grown after rape or flax. Soybean grown after barley and wheat may be included in the different systems studied without yield losses. Volunteer white oat seeds may reduce soybean yield and plant height.

The effects of soil tillage methods and winter crop rotation on soybean yield were assessed over a ten-year period. Four soil tillage methods — 1) no-tillage continuous; 2) minimum tillage in winter and no-tillage in summer; 3) conventional tillage with disk plow in winter and no- tillage in summer; and 4) tillage using a moldboard plow in winter and no-tillage in summer—and three crop rotation systems [system 1 (wheat/soybean), system II (wheat/soybean and common vetch/corn or sorghum), and system III (wheat/soybean, black oats or white oats/soybean, and common vetch/corn or sorghum)] were compared. An experimental randomized blocks design with split-plots and three replications was used. Soybean yields under conventional soil tillage with disk plow'minimum tillage, and no-tillage were the highest. The yield of soybean grown after wheat, in system II, was higher than soybean grown afier black oats or white oats, after wheat, in system III, and after wheat, in system I. The lowest soybean yield was obtained in monoculture . 

The experiment was conducted in Ituporanga, SC, Brazil for a period of three years, and it aimed to evaluate perennial grasses. The climate in the region is humid subtropical — Cfa, and the soil is the Distrofic Alie Cambissol type, which was limed and fertilized. The species tested in completely experimental design with two replicates were: Hemarthria altissima (fifleen entries); Axonopus sp (five entries); Paspalum notatum (three entries); Paspalum notatum (one cultivar); Cynodon sp. (one cultivar). The most productive treatments were: Paspalum notatum entrie EEL 10162 (CP 13,9%, IVDOM 49% and 20559 kg/ha DM); Axonopus sp. entries Missioneira Gigante (CP 12%, IVDOM 61,8% and 18469 kg/ha DM) and Taió (CP 14,5%, IVDOM 53,1% and 19077 kg/ha DM); Hemarthria altissima entries IAPAR — 35 — Roxinha (CP 10,8%, IVDOM 44,8% and 17068 kg/ha DM), PI 349798 (CP 11,7%, IVDOM 56,9% and 16273 kg/ha DM), PI — HM — 365509 (CP 11,4%, IVDOM 55,5% and 15466 kg/ha DM), and IAPAR — 36 — Flórida (CP 11,2%, IVDOM 60,2% and 14659 kg/ha DM); Cynodon sp. cultivar Tifton 85 (CP 14,1%, IVDOM 50,2% and 19784(CP 13,9%, IVDOM 49% and 20559 kg/ha DM) kg/ha DM). 

The objective of this study was to develop a micropropagation protocol for maté, which included the following experiments: I) Exam of culture medium contamination by microorganisms and in vitro development of explants; II) Pre-treatment of donor plants with the fungicides mancozeb and benomyl, amendment of ANA culture medium with various leveis of benomyl and rifampicin; III) Development of erva-mate explants in culture medium with different rates of cytokinin (BAP); IV) Mass propagation and root development of explants in two culture media (with agar + IBA or vermiculita + IBA). The fungi Alternaria sp. and Colletotrichum sp. were identified contam inating micropropagated explants and causing plant death. Bacteria were also found but they did not affect explant development. Pre-treatment of donor plants with fungicide reduced in vitro contamination by 90%. The use of 0.2 to 0.8 mg BAP in the culture medium did not stimulate shoot formation and did not influence leaf number. The rooting medium with IBA and vermiculita was more efficient on elongation and subsequent root emission.

The probability of occurrence of low values of solar radiation, which are harmful to cucumber, was calculated in thel3aixo Vale do Taquari Region, Rio Grande do Sul State, Brazil. Daily data of solar radiation from 1963 to 1999 obtained in the meteorological station of Taquari (Latitude: 29° 48' S, Longitude: 51° 41W, Altitude: 75 m) were used. The following threshold values were used in this study: 8.4, 7.5 and 6.3 MJ/m 2.day. The first value was the threshold levei for growth and development of cucumber, and the other two leveis were the cause of serious yield tosses. The results showed that during the second and third decades of July the probability of occurring these threshold values of solar radiation is high: up to 9 days in each decade can be expected to have solar radiation lower than 8.4 and 7.5 MJ/m2.day.

Predatory coccinelids were surveyed in citric plants fortnightly at orchards in Viamão for 4 months (from August to November, 1998) and in Porto Alegre for 5 months (from December, 1998 to April, 1999), Rio Grande do Sul state. The research was conducted at private properties where insecticides were not used in the orchards. Baiting trays were used randomly to catch the specimens. Thirteen species of 13 genera totaling 276 specimens were collected, with the predominance of lady beetles Coccidophilus citricola Bréthes, 1905, which feed preferentially on scale insects of the family Diaspididae.

The State of Rio Grande do Sul, southem Brazil has 10 million hectares of native pastures and soils with high acidity and phosphorus deficiency, requiring liming and fertilization to improve productivity. An experiment was carried out at Centro de Pesquisas em Forrageiras, in São Gabriel county, Rio Grande do Sul, Brazil, aiming to study the residual effect of superficial liming and fertilization on dry matter yield of native pasture and on some soil chemical characteristics. A split-plot experimental design with randomized blocks and three replications was used. Treatments were limestone (zero, 4,3 and 8,6t.ha') with annual fertilization (45 kg.ha' de N, 110 kg.ha' de P2O5 e 60 kg.ha-' de K2O) and without fertilization and two depths (0-3cm and 3-6cm). The limestone was applied on February, 1994 and fertilizations were annual since February, 1994 until February, 1996. Soil and forage samples were collected by October, 1997. Fertilization showed a residual positive effect, increasing dry matter yield of native pasture. On the other hand, limestone application decreased exchangeable AI ¨3  and increased pH and  availability of soil Ca" and Mr.