ABSTRACT The black oats (Avena strigosa S.) is an excellent forage plant, besides acting in the system of rotation and succession of cultures. In recent decades, oat genetic improvement programs have worked intensively to select materials that are more responsive to pests and diseases, in addition to seeking greater mass and grain productivity. However, these new materials need to be tested for agronomic performance in different seeding systems. Given the importance of culture, the objective of this work was to evaluate the agronomic performance of black oats conducted with two sowing methods. The treatments were arranged in blocks at random in a 2x2 factorial arrangement, that is, two sowing methods (at haul and row) and two cultivars (UPFA 21 - Moreninha and EMBRAPA 139), with five replications, in a useful area of 7.15 m2 per plot. Sixty days after sowing, the cultivars were evaluated for height, total fresh phytomass production (TFF) and total dry phytomass (TDP). The results indicated statistically significant differences in the production of TFF and TDP between cultivars and between sowing methods, being the cultivar UPFA 21 - Moreninha more productive, in addition to presenting better results in the sowing system in line. There were no significant differences in plant height between the treatments evaluated. However, sowing in line allowed greater production of TFF and TDP for the cultivar UPFA 21 - Moreninha.

RESUMO A aveia preta (Avena strigosa S.) é uma excelente planta forrageira, além de atuar no sistema de rotação e sucessão de culturas. Nas últimas décadas, os programas de melhoramento genético de aveia tem atuado de forma intensa na seleção de materiais mais responsivos a pragas e doenças, além de buscar maior produtividade de massa e grãos. Contudo, estes novos materiais precisam ser testados com relação ao desempenho agronômico em diferentes sistemas de semeadura. Diante da importância da cultura, o objetivo deste trabalho foi avaliar o desempenho agronômico da aveia preta conduzida com dois métodos de semeadura. Os tratamentos foram dispostos em blocos ao acaso em arranjo fatorial 2x2, com dois métodos de semeadura (a lanço e na linha) e duas cultivares (UPFA 21 Moreninha e EMBRAPA 139), com cinco repetições, em área útil de 7,15 m2 por parcela. Sessenta dias após a semeadura, as cultivares foram avaliadas quanto à altura de planta, produção de Fitomassa Fresca Total (FFT) e Fitomassa Seca Total (FST). Os resultados indicam diferenças estatísticas significativas na produção de FFT e FST entre as cultivares e entre os métodos de semeadura, sendo a cultivar UPFA 21 - Moreninha mais produtiva, além desta apresentar melhores resultados no sistema de semeadura em linha. Não foram observadas diferenças significativas na altura de planta entre os tratamentos avaliados. Porém, a semeadura em linha permitiu maior produção de FFT e FST para a cultivar UPFA 21 - Moreninha.

RESUMO A produção de suínos confinados gera efluentes que quando aplicados no solo servem como fonte de fertilizante e quando aplicados sem tratamento adequado alteram a qualidade ambiental. Estes dejetos contêm elementos potenciais contaminantes cuja aplicação excessiva gera acúmulo de materiais e podem ocasionar efeitos tóxicos para as plantas, como na germinação de sementes. Neste estudo objetivou-se analisar o efeito de doses de dejetos líquidos de suínos (DLS) sobre a germinação de três culturas de grãos de interesse agrícola. Os ensaios foram realizados em condições de laboratório com sementes de soja, trigo e milho, que foram dispostas em placas de Petri, na quantidade de dez sementes por placa. Foram aplicadas doses tratamentos de DLS, caracterizado quimicamente, correspondentes a 0, 1,4 e 2,1 xDP (vezes a Dose Padrão) m³ ha-1 com três repetições. As placas foram colocadas na BOD em temperatura 24 0C. Os dados obtidos foram analisados pelo teste de Tukey (5%). Aos sete dias do início do ensaio foi determinada a porcentagem de germinação. O DLS possui em sua composição alguns elementos potenciais contaminantes, como o cobre, o zinco e o amônio, os quais podem ocasionar prejuízos na germinação de diversas culturas, sobretudo com exposição direta das sementes nas placas de Petri. As sementes de soja e trigo sofreram efeito negativo da aplicação de DLS apresentando redução na taxa de germinação com o uso de 1,4 e 2,1 xDP m³ ha-1. A aplicação do equivalente a 1,4 e 2,1 xDP m³ ha-1 de DLS não afetaram significativamente a germinação de sementes de milho.

ABSTRACT Pig production generates effluents that, when applied to the soil, serve as a source of fertilizer and, when applied without adequate treatment, alter the environmental quality. These wastes contain potential contaminating elements whose excessive application generates an accumulation of materials and can cause toxic effects for plants, such as seed germination. This study aimed to analyze the effect of doses of pig slurry (SP) on seed germination of three grain crops of agricultural interest. The assays were carried out under laboratory conditions with soybean, wheat, and corn seeds placed in Petri dishes, with ten seeds per dish. SP doses/treatments, chemically characterized, corresponding to 0, 1,4, and 2,1 tSD (times the Standard Dose) m³ ha-1 were applied with three replicates. The plates were placed in the BOD at temperature 24°C. The data obtained were analyzed using the Tukey test (5%). Seven days from the beginning of the trial, the percentage of germination was determined. SP has in its composition some potential contaminating elements, such as copper, zinc, and ammonium, which can cause damage to the germination of several cultures, especially with direct exposure of the seeds in Petri dishes. Soybean and wheat seeds were significantly affected by the application of SP, showing a reduction in the germination rate with the use of 100 and 150 m³ ha-1. The application of the equivalent of 1,4, and 2,1 tSD m³ ha-1 of SP did not significantly affect the germination of maize seeds.

RESUMO A produção de tabaco no Brasil é uma importante fonte de renda para muitas famílias, principalmente na região sul do País. No entanto, está sujeita ao ataque de pragas e doenças, como o inseto fungus gnats. Como alternativas ao controle dessa praga, encontra-se no solo brasileiro o ácaro Stratiolaelaps scimitus, que apresenta potencial predatório ao fungus gnats. O objetivo desse estudo foi avaliar o uso do S. scimitus como agente de controle do inseto, comparado ao químico, na produção de mudas de tabaco no sistema floating. O experimento foi conduzido em uma propriedade rural no município de Crissiumal-RS, em delineamento em blocos ao acaso, com quatro repetições: T1= controle, T2= químico a base de Imidacloprido e Azadiractina e T3= S. scimitus. Para análise da eficiência de controle, foram realizadas capturas de insetos adultos em diferentes épocas, e o controle biológico não diferiu do controle químico. O tratamento biológico possibilitou redução no uso de produtos químicos. De forma concomitante, verificou-se por meio de questionários, que o novo modelo de controle está sendo bem aceito pelos produtores. Portanto, a utilização de S. scimitus foi capaz de reduzir a proliferação de fungus gnats na produção de mudas de tabaco no sistema floating, porém mais estudos precisam ser realizados para melhor avaliação. famílias País entanto doenças praga encontrase encontra se S floating CrissiumalRS, CrissiumalRS Crissiumal RS, RS Crissiumal-RS acaso repetições T1 T T2 T3 épocas químicos concomitante verificouse verificou questionários produtores Portanto avaliação

ABSTRACT Tobacco production in Brazil is an essential source of income for many families, especially in the southern region. However, it is subject to attack by pests and diseases, such as the fungus gnats insect. To control this pest, the mite Stratiolaelaps scimitus is found in Brazilian soil, which has a predatory potential to fungus gnats. This study aimed to evaluate the use of S. scimitus as an insect control agent, compared to chemical control, in the production of tobacco seedlings in the floating system. The experiment was carried out on a farm in Crissiumal-RS, in a randomized block design, with four replications: T1= control, T2= chemical control based on Imidacloprid and Azadirachtin, and T3= S. scimitus. To analyze the control efficiency, adult insects were captured at different times, and the biological control did not differ from the chemical control. The biological treatment made it possible to reduce the use of chemical products. Concomitantly, questionnaires verified that producers are well accepting the new control model. Therefore, using S. scimitus could reduce the proliferation of fungus gnats in the production of tobacco seedlings in the floating system, but more studies need to be carried out for a better evaluation. families region However diseases pest soil S agent system CrissiumalRS, CrissiumalRS Crissiumal RS, RS Crissiumal-RS design replications T1 T T2 Azadirachtin T3 efficiency times products Concomitantly model Therefore evaluation

ABSTRACT Milk is one of the richest food sources of nutrients and vitamins for humans, mainly due to its calcium content and high quality proteins. Due to the importance of this food, the milk production chain is one of the segments that has generated huge socioeconomic impacts on the national scene, which has undergone countless transformations in the last decades. Thus, the objective of this work was to study the main factors responsible for the evolution of the milk production chain in the municipalities of Três Passos and Tiradentes do Sul, RS, Brazil. To this end, a field survey was carried out, where a semi-structured questionnaire was applied, addressed to 20 producers that develop activities in the area of milk production in these municipalities. It was found that the adoption of technological innovations was the fundamental point for the dairy activity to undergo expressive changes in recent years, both in the quantity and in the quality of the milk produced, being the factor responsible for the improvement and enhancement of the sector. Therefore, the modernization and implementation of technological innovations are fundamental factors for the positive changes that have occurred in the dairy sector.

RESUMO O leite é uma das fontes de alimentação mais ricas em nutrientes e vitaminas para os seres humanos, principalmente devido ao seu teor de cálcio e proteínas de alta qualidade. Devido à importância deste alimento, a cadeia produtiva do leite é um dos segmentos que tem gerado enormes impactos socioeconômicos no cenário nacional, a qual sofreu inúmeras transformações nas últimas décadas. Dessa forma, o objetivo deste trabalho foi estudar os principais fatores responsáveis pela evolução da cadeia produtiva do leite nos municípios de Três Passos e Tiradentes do Sul, RS, Brasil. Para tal, foi realizada uma pesquisa a campo, onde foi aplicado um questionário semiestruturado, dirigido a 20 produtores que desenvolvem atividades na área de produção de leite nestes municípios. Constatou-se que a adoção de inovações tecnológicas foi o ponto fundamental para que a atividade leiteira passasse por mudanças expressivas nos últimos anos, tanto na quantidade quanto na qualidade do leite produzido, sendo o fator responsável pelo aprimoramento e potencialização do setor. Portanto, a modernização e a implantação de inovações tecnológicas são fatores fundamentais para as mudanças positivas ocorridas no setor leiteiro.

ABSTRACT The objective of this study was to evaluate the diversity and abundance of edaphic fauna organisms in single and intercropped systems of sweet potato (Ipomoea batatas) and ecologically-based popcorn (Zea mays) in Red Oxisol, in the Northwest region of the state of Rio Grande do Sul, Brazil. Four sweet potato cultivars were used in single systems and intercropped with popcorn: BRS Amélia, BRS Rubissol, BRS Cuia and Crioula. The soil fauna assessment was carried out using PROVID-type traps. Richness, abundance and the dominance indices of Shannon (H’) and Simpson (D) were determined. The orders Coleoptera, Hymenoptera, Collembola and Orthoptera, were dominant in both cultivation systems. The single cultivation showed a greater number of organisms in the orders Isopoda and Collembola, whereas in the intercropped system, the orders Lepidoptera and Hymenoptera stood out. The intercropping cultivation of sweet potato and popcorn shows highest diversity and abundance of soil organisms compared to the single cultivation.

Resumen La batata (Ipomoea batatas L.) es una hortaliza de gran importancia económica ya que se puede utilizar para el consumo de natura, para el procesamiento en agronegocios y/o la producción de biocombustibles. El objetivo de este trabajo es evaluar el rendimiento de tres cultivares de batata: BRS Amelia, BRS Cuia y BRS Rubissol en la región noroeste de Rio Grande do Sul. El experimento se realiza en el campo durante dos años consecutivos (cosechas 2014/2015 y 2015/2016). El diseño experimental fue en bloques al azar, evaluando 3 cultivares de camote durante 2 años agrícolas, con 4 repeticiones. Como resultados, se observa que el peso de la papa en el primer año de estudio varía de 272.0 g a 320.2 g. En el segundo año de evaluación, varía de 133.9 g a 247.1 g. En relación con la productividad promedio, los valores obtenidos en el primer año fueron 15.2 t ha-1 para BRS Amelia, 19.8 t ha-1 para BRS Cuia y 16.2 t ha-1 para BRS Rubissol. En el segundo año de evaluación, los valores fueron 12.3 t ha-1 para BRS Amelia, 16.1 t ha-1 para BRS Cuia y 13.1 t ha-1 para BRS Rubissol. Los cultivares presentaron rendimientos más altos que el promedio nacional de Brazil en los dos años evaluados.

Abstract The sweet potato (Ipomoea batatas L.) is a vegetable of great economic importance since it can be used for in natura consumption, for processing in agribusiness and/or biofuel production. The objective of this work was to evaluate the yield of three sweet potato cultivars: BRS Amelia, BRS Cuia and BRS Rubissol in the Northwest Region of Rio Grande do Sul. The experiment was conducted in the field for two consecutive years (harvests 2014/2015 and 2015/2016). The experimental design was in randomized blocks, evaluating 3 sweet potato cultivars for 2 agricultural years, with 4 replications. As results, it was observed that potato weights in the first year of study ranged from 272.0 g to 320.2 g. In the second year of evaluation, it ranged from 133.9 g to 247.1 g. In relation to the average productivity, the values obtained in the first year were 15.2 t ha-1 for BRS Amelia, 19.8 t ha-1 for BRS Cuia and 16.2 t ha-1 for BRS Rubissol. In the second year of evaluation, the values were 12.3 t ha-1 for BRS Amelia, 16.1 t ha-1 for BRS Cuia and 13.1 t ha-1 for BRS Rubissol. Cultivars presented yields higher than the national average from Brazil in the two evaluated years.

Resumo O guabijuzeiro (Mycianthes pungens (O. Berg) Legrand) é uma frutífera que apresenta grande potencial para exploração comercial de seus frutos devido às suas características nutricionais. O objetivo deste trabalho foi estudar o ciclo reprodutivo de M. pungens, entre os anos de 2014 e 2015, em distintas regiões do Rio Grande do Sul: acessos de guabijuzeiros dos municípios de Três Passos (região noroeste), Paraí e Guabiju (região nordeste) e Porto Alegre (região Metropolitana). Como resultados, observaram-se variação na fenologia e soma térmica entre os acessos, sendo que, em Três Passos, o ciclo reprodutivo teve duração de 95 dias e atingiu soma térmica de 1.290 °C. No município de Guabiju, o ciclo reprodutivo teve duração de 147 dias, e a soma térmica foi de 1.603 °C. No município de Porto Alegre, o ciclo reprodutivo foi de 133 dias, e a soma térmica, de 1.564 °C.

Abstract Guabiju (Mycianthes pungens (O. Berg) Legrand) is a fruit tree with great potential for commercial exploitation due to its nutritional characteristics. The aim of this work was to study the reproductive cycle of M. pungensin different regions of Rio Grande do Sul. Phenology was monitored from September 2014 to February 2015 in the municipalities of Três Passos (Northwestern region), Parai and Guabiju (Northeastern region), and Porto Alegre (Metropolitan region). As results, variations in reproductive cycle and thermal sum among accessions were observed, and in Três Passos, the reproductive cycle had duration of 95 days and reached thermal sum of 1290°C. In the municipality of Guabiju, the reproductive cycle lasted 147 days and the thermal sum was 1603°C. In the municipality of Porto Alegre, the reproductive cycle had duration of 133 days and the thermal sum reached 1564°C.

ABSTRACT Trifolium polymorphum Poir. is an amphicarpic forage legume from southern Brazil, Uruguay, Argentina, Paraguay and Chile. Information on the genetic diversity of natural populations in natural grasslands in southern Brazil is limited. In order to increase the knowledge about this species, an analysis of the genetic diversity was carried out in 10 natural populations of T. polymorphum with the use of 20 microsatellite markers. The expected heterozygosity in T. polymorphum populations ranged from 0.40 to 0.43, with a mean of 0.42. A total of 193 alleles were detected with a mean of 9.3 alleles per locus and polymorphic information content (PIC) for these markers of 0.62 to 0.89 with a mean of 0.84.The grouping based on the Jaccard’s coefficient of similarity classified populations, regardless of their regions of origin, into two groups with a mean similarity coefficient of 0.32, reflecting the high genetic variability of the populations, especially those located in the Campanha phytogeographic region. This information on diversity can be used to plan future germplasm collection strategies for conservation purposes and also for the breeding of the species.

ABSTRACT: Seedlessness in fruit is a trait that is much sought after by juice making industries. Close to the city of São Sebastião do Caí, in the state of Rio Grande do Sul (RS), Brazil, a new mutant orange originating from natural mutation was identified and selected as a seedless material. To determine the mechanisms involved in the absence of seeds, the reproductive structures of this new mutant by comparison with a Valencia sweet orange as control, a cultivar with a profusion of seeds, was analyzed in terms of meiotic behavior, meiotic index, pollen viability, in vitro germination, and ovule features to determine the grounds for seed absence. Other morphological analyzes allowed for visualizing the structures of normal appearance and size in both cultivars. Meiotic analysis identified chromosome normal pairing with a predominance of bivalents at diakinesis and metaphase 1. URS Campestre flowers at different developmental stages had anthers and ovaries whose dimensions are typical while pollen grain analysis pointed to a standard developmental pattern, normal meiosis, high viability (84 %) and elevated in vitro pollen tube germination rates (63 %). The cv. Valencia and URS Campestre ovules had a similar shape and morphology, sharing an anatropous orientation, and two integuments. In the internal ovule analyses of Valencia sweet oranges, normal embryo sac cells were identified: presence of one egg cell and two synergids, three antipodes and a bigger and central cell containing two polar nuclei. However, the analysis of ovules from URS Campestre reveals an apparent senescence or non-formation of an embryo sac, where only a few highly stained and collapsed cells could be identified. These results led to the conclusion that female sterility in URS Campestre, with a total absence of a female gametophyte, is the limiting factor for fertilization and seed production.

ABSTRACT The aim of this study was to determine the mode of reproduction of a hybrid progeny derived from intraspecific crosses of Paspalum notatum through cytoembryological analysis and use of RAPD (random amplification of polymorphic DNA) molecular markers. Cytoembryological analysis allowed identification of the mode of reproduction of 28 plants that were selected after agronomic productivity evaluations. Of these, 19 had embryo sac morphology compatible with an apomictic mode of reproduction and nine had embryo sac morphology compatible with a sexual mode of reproduction. Meanwhile, molecular marker analysis for 194 individuals showed 54 sexual and 140 apomictic plants; of the 28 plants analyzed by the two methods, ten results (35.7%) were in disagreement. In this paper, through cytoembryological analyses, a ratio of 1:2.1 of sexual to apomictic plants was found. The BCU 243 marker showed a stable pattern of amplification, but some results differed with cytoembryological analyses, demonstrating that these analyses are more reliable when determining the mode of sexual reproduction for the plants of P. notatum. Apomictic plants characterized in this work can be tested in the field to check their agronomic value and registration as plant varieties, while the sexual plants can be used as potential parents in future crosses.

Abstract This study aimed to evaluate the genetic and cytological diversity and stability of 35 cherry tree accessions collected in Rio Grande do Sul. We used 15 RAPD (Random Amplified Polymorphic DNA) molecular markers and performed cytological analysis and number count of anthers. Analyses of genetic diversity allowed the separation of accessions into four groups, resulting in an average of 8.93 bands per primer amplified, 7.89 polymorphic bands, 88.08% of polymorphism and 86% of genetic similarity. Cytological analyses of gametic cells allowed for the characterization of accessions as diploids with n=11. In these, the average of meiotic cells considered normal was 82.12%; average pollen viability was 92.44% and in vitro germination was 40.26%; the average number of anthers was 161.85 anthers/flowers. Therefore, the accessions evaluated showed high genetic similarity and cytological stability and can be used in commercial plantations or hybridizations.

Abstract The objective of this study was to identify polyploid plants from citrus rootstocks and to evaluate the influence of the genetic constitution and of the environment on the frequency of chromosome duplication. Populations obtained from rootstock seeds of Trifoliata [Poncirus trifoliate (L.) Raf], citrumelo 'Swingle' [C. paradise Macf. × P. trifoliate], citrange 'Troyer' [C. sinensis (L.) Osb. x P. trifoliate] and citranges Fepagro 'C13', 'C37' and 'C41' [C. sinensis (L.) Osb. cv. Pêra x P. trifoliata] were evaluated under field and greenhouse conditions. Flow cytometry analysis of 415 field plants and 435 greenhouse plants identified seven (1.69%) and 29 (6.67%) tetraploids, respectively. Differences in the number of tetraploid plants among genotypes and locations were observed in field progenies of 'C 37' (2.12%) and 'C 13' (2.04%) and in greenhouse progenies of 'C 13' (15.52%) and 'C 37' (6%). The frequency of autotetraploidization events in citrus rootstocks is common and appears to be associated to genetic constitution and environmental conditions.

Resumo Elionurus muticus é uma gramínea aromática nativa do bioma Pampa, que produz um óleo essencial rico em citral. Apesar da importância do citral, poucos estudos têm sido realizados para esta espécie. Os objetivos deste trabalho foram avaliar a estrutura genética e caracterizar citogenéticamente populações naturais de E. muticus do sul do Brasil. A caracterização genética foi realizada utilizando marcadores AFLP e a citogenética avaliou o número de cromossomos, cariótipo e meiose. As populações estudadas apresentaram variabilidade genética, especialmente dentro das populações, indicando a possibilidade de seleção de plantas com caracteres relevantes. A alta variabilidade também sugere a ocorrência preferencial de alogamia nas populações naturais. A meiose observada na análise citogenética foi regular, com número cromossômico 2n=20. O cariótipo da espécie é apresentado pela primeira vez, com a fórmula cariotípica 3sm + 4a + 1saSAT.

Abstract Elionurus muticus is a native aromatic grass from the Pampa biome that produces an essential oil that is rich in citral. Despite the importance of citral, few studies have examined this species. The aims of this work were to evaluate the genetic structure and to characterize cytogenetically natural populations collected from Brazil. Genetic characterization was performed using AFLP markers, and cytogenetics assessed the chromosome number, karyotype and meiosis. The studied populations had genetic variability, especially within populations, indicating the possibility of selecting plants with relevant characters. High variability also suggests the preferential occurrence of outcrossing in natural populations. Regular meiosis was observed in the cytogenetic analysis with chromosome number 2n=20. The karyotype of the species is presented for the first time, with the karyotype formula 3sm + 4a + 1saSAT.

Paspalum notatum é uma das mais importantes espécies das pastagens nativas do Sul do Brasil, que é a principal fonte forrageira para a pecuária. Os ecótipos nativos são tetraploides e de reprodução apomítica, o que impede o registro e a proteção de cultivares. Porém, uma variedade cultivada, Paspalum notatum var. saurae (cultivar Pensacola) é diplóide e sexual. O objetivo deste trabalho foi de poliploidizar artificialmente plantas de cv Pensacola, para serem utilizadas como genitores femininos em cruzamentos com genitores masculinos tetraploides e apomíticos. Plântulas e sementes foram tratadas por imersão com soluções de colchicina por tempo de exposição variável. Três plantas confirmaram número cromossômico tetraploide. As plantas polyploides obtidas serão avaliadas quanto ao modo de reprodução; se confirmarem ser sexuais, serão utilizadas nos esquemas de cruzamentos com plantas apomíticas nativas para obtenção de novos híbridos intraespecíficos.

Paspalum notatum is one of the most important native grassland species of southern Brazil, and the main forage source for livestock. The native ecotypes are tetraploid and have apomictic reproduction, which prevents the registration and protection of plant varieties. However, the cultivated variety Paspalum notatum var. saurae (cultivar Pensacola) is diploid and sexual. The objective of this study was to artificially produce polyploid cv. Pensacola plants, to be used as female parents in crosses with male tetraploid and apomictic parents. Seedlings and seeds were immersed in colchicine solutions for different periods. A tetraploid chromosome number was confirmed in three plants. The reproduction mode of the resulting polyploid plants will be assessed; if confirmed to be sexual, they can be used in crosses with native apomictic plants to breed new intraspecific hybrids.

Porta-enxertos cítricos tetraploides podem apresentar características morfológicas e desenvolvimento diferenciados comparados a plantas diploides. Este trabalho teve como objetivo avaliar características morfológicas e o crescimento em altura de plantas diploides e tetraploides dos porta-enxertos citrumelo Swingle [C. paradisi Macf. x Poncirus trifoliata (L.) Raf], citrange Troyer [C. sinensis (L.) Osb. x P. trifoliata] e dos citranges Fepagro C 13 e Fepagro C 37 (C. sinensis cv. Pêra x P. trifoliata) por um período de 12 meses. Plantas diploides (2n=18) e tetraploides (2n=36) oriundas da mesma semente foram identificadas, estabelecidas e avaliadas a cada 45 dias quanto a cor, altura, comprimento do pecíolo, da folha e largura do limbo do folíolo central. Diferenças significativas foram observadas nos caracteres avaliados: a média do comprimento do pecíolo nas plantas diploides foi de 1,78 cm e, nas tetraploides, de 0,99 cm; a média do comprimento das folhas nas diploides foi de 2,32cm e nas tetraploides de 2,95 cm; a média de largura dos folíolos centrais das folhas das plantas diploides foi de 1,33 cm e, nas tetraploides, de 1,69 cm; além disso, as plantas tetraploides apresentaram folhas com coloração mais escura e mais espessas do que as das diploides. Variações foram observadas na altura, com as plantas diploides apresentando maior crescimento que as tetraploides. Portanto, plantas tetraploides apresentam menor tamanho, crescimento em altura mais lento e folhas mais largas e compridas.

Tetraploid citrus rootstocks may present different morphological characteristics and growth when compared to diploid ones. This worked aimed at comparing morphological characteristics and height growth of diploid and tetraploid plants from the rootstocks 'Swingle' citrumelo [C. paradise Macf. x Poncirus trifoliate (L.) Raf], citrange 'Troyer' (C. sinensis (L.) Osb. x P. trifoliata) and citranges 'Fepagro C 13' and 'Fepagro C 37' [C. sinensis cv. Pêra x P. trifoliata] during twelve months. Diploid (2n=18) and tetraploid (2n=36) plants originated from the same seed were identified, cultivated and evaluated every 45 days regarding color, height, petiole length, leaf length and central leaflet width. Significant differences were observed for the evaluated characteristics: the average of petiole length was 1.78 cm in the diploid and 0.99 cm in the tetraploid plants; the average of leaf length was 2.32 cm in the diploid and 2.95 cm in the tetraploid plants; the average of central leaflet width was 1.33 cm in the diploid and 1.69 cm in the tetraploid plants. Moreover, tetraploid plants had darker and thicker leaves than the diploid ones. Variation regarding height was observed and the diploid plants presented higher growth than the tetraploid ones. As tetraploid plants are smaller, have a slow height growth and wider and longer leaves.