ABSTRACT. The selection of superior sweet potato genotypes using Bayesian inference is an important strategy for genetic improvement. Sweet potatoes are of social and economic importance, being the material for ethanol production. The estimation of variance components and genetic parameters using Bayesian inference is more accurate than that using the frequently used statistical methodologies. This is because the former allows for using a priori knowledge from previous research. Therefore, the present study estimated genetic parameters and selection gains, predicted genetic values, and selected sweet potato genotypes using a Bayesian approach with a priori information. Root shape, soil insect resistance, and root and shoot productivity of 24 sweet potato genotypes were measured. Heritability, genotypic variation coefficient, residual variation coefficient, relative variation index, and selection gains direct, indirect and simultaneous were estimated, and the data were analyzed using Bayesian inference. Data from 11 experiments were used to obtain a priori information. Bayesian inference was a useful tool for decision-making, and significant genetic gains could be achieved with the selection of the evaluated genotypes. Root shape, soil insect resistance, commercial root productivity, and total root productivity showed higher heritability values. Clones UFVJM06, UFVJM40, UFVJM54, UFVJM09, and CAMBRAIA can be used as parents in future breeding programs.

Abstract The objective of this work was to select sweet potato (Ipomoea batatas) genotypes with leaves with potential to be used for human consumption. Twenty-six experimental genotypes and four commercial cultivars were tested in a randomized complete block design with three replicates and ten plants per plot. The trial was carried out in the municipality of Lavras, in the state of Minas Gerais, Brazil. Leaf shape and lobe, aerial-part yield, edible-leaf yield, edible-leaf percentage, edible-leaf dry mass, and latex production, as well as leaf total chlorophyll, pH, soluble solids contents, titratable acidity, total phenolic compounds, and anthocyanin contents, were evaluated. Roots were characterized as to their pulp and peel colors. Fifteen genotypes presented the highest aerial-part (29.6 to 51.8 Mg ha-1) and edible leaf (7.8 to 12.7 Mg ha-1) yields. In the biochemical analysis, high contents of chlorophyll, total phenolics, and anthocyanins were observed. In addition, pH, soluble solids, and leaf titratable acidity did not differ significantly among the evaluated genotypes. Leaves of ten genotypes are recommended for human consumption.

Resumo O objetivo deste trabalho foi selecionar genótipos de batata-doce (Ipomoea batatas) com folhas com potencial para serem usadas para consumo humano. Vinte e seis genótipos experimentais e quatro cultivares comerciais foram testados em delineamento de blocos ao acaso, com três repetições e dez plantas por parcela. O ensaio foi realizado no município de Lavras, no estado de Minas Gerais, Brasil. Foram avaliados formato e lóbulo da folha, produção da parte aérea, produção de folhas comestíveis, percentagem de folha comestível, massa seca de folha comestível e produção de látex, bem como clorofila total, pH, conteúdo de sólidos solúveis, acidez titulável, compostos fenólicos totais e teor de antocianinas das folhas. As raízes foram caracterizadas quanto às cores da sua polpa e casca. Quinze genótipos apresentaram as maiores produtividades de parte aérea (29,6 a 51,8 Mg ha-1) e de folhas comestíveis (7,8 a 12,7 Mg ha-1). Nas análises bioquímicas, foram observados altos teores de clorofila, compostos fenólicos totais e antocianinas. Além disso, pH, sólidos solúveis e acidez titulável foliar não diferiram significativamente entre os genótipos avaliados. As folhas de dez genótipos são recomendadas para alimentação humana.

Resumo O objetivo deste trabalho foi avaliar as correlações fenotípicas entre características agronômicas de alho (Allium sativum) e realizar análise de trilha, tendo-se utilizado a produtividade comercial de bulbos como característica principal. O experimento foi conduzido sob condições de campo em duas safras (2018 e 2019), no município de Diamantina, no estado de Minas Gerais, Brasil. Um total de 13 genótipos de alho foram avaliados, sendo 11 experimentais e 2 cultivares comerciais. Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repetições. Foram avaliadas características relacionadas à biometria da planta e à produção de bulbos. Foram realizadas as correlações fenotípicas e a análise de trilha das características estudadas. As correlações fenotípicas que apresentaram efeito positivo significativo ocorreram entre produção comercial de bulbos e altura de planta, diâmetro do bulbo, número de bulbos comerciais, massa média de bulbo total, massa média de bulbo comercial, produtividade total de bulbos e número de bulbilhos por bulbo. No entanto, apenas o número de bulbos comerciais e o diâmetro do bulbo tiveram efeitos significativos (direto e indireto) sobre a produtividade comercial de bulbos. Portanto, em programas de melhoramento de genótipos na região estudada, a seleção deve buscar maior diâmetro de bulbos e maior número de bulbos comerciais para incrementar a produtividade comercial.

Abstract The objective of this work was to evaluate the phenotypic correlations between agronomic characters of garlic (Allium sativum) and to carry out the path analysis, using commercial bulb yield as the main character. The experiment was conducted under field conditions in two harvests (2018 and 2019) in the municipality of Diamantina, in the state of Minas Gerais, Brazil. A total of 13 garlic genotypes were evaluated, of which 11 were experimental and 2 were commercial cultivars. The experimental design used was randomized complete blocks with four replicates. Characters related to plant biometry and bulb yield were evaluated. The phenotypic correlations and the path analysis of the studied characters were carried out. The phenotypic correlations that showed significant positive effects occurred between commercial bulb yield and plant height, bulb diameter, number of commercial bulbs, mean total bulb mass, mean commercial bulb mass, total bulb yield, and number of bulbils per bulb. However, only number of commercial bulbs and bulb diameter had significant effects (direct and indirect) on commercial bulb yield. Therefore, in genotype genetic breeding programs in the studied region, selection should seek a larger diameter of bulbs and a higher number of commercial bulbs to increase commercial yield.

Resumo: A couve (Brassica oleracea var. acephala) apresenta grande importância devido a sua facilidade de propagação, aceitabilidade e às suas propriedades nutracêuticas. O objetivo no presente trabalho foi realizar ajustes metodológicos para a condução do teste de tetrazólio em sementes de couve. Inicialmente foram realizados pré-testes com relação ao tempo de pré-condicionamento a 20 °C por 10 e 14 horas (tempos definidos pela curva de embebição) e métodos de remoção do tegumento das sementes de couve (remoção total do tegumento; corte na região distal ao eixo embrionário; corte longitudinal no maior sentido e sementes inteiras). Posteriormente, as metodologias mais eficientes foram avaliadas usando diferentes concentrações da solução do sal de tetrazólio (0,075%; 0,2%; 0,5% e 1,0%) e tempos (2, 4 e 6 h) de imersão das sementes na solução, utilizando-se quatro lotes. As sementes foram analisadas individualmente e classificadas como viáveis ou não viáveis. O teste de tetrazólio é eficiente para a avaliação da viabilidade de sementes de couve fornecendo resultados correlacionados com a germinação. As sementes de couve devem ser pré-condicionadas entre papel por 10 horas a 20 °C, e ter o tegumento removido para imersão em solução do sal de tetrazólio a 0,5% por 4 horas a 30 °C.

Abstract: Kale (Brassica oleracea var. acephala) has great importance due to its easy propagation, acceptability and nutraceutical properties. The aim of the present work was to make methodological adjustments to conduct the tetrazolium test in kale seeds. Pre-tests were initially carried out to assess the priming time at 20 °C for 10 and 14 hours (times defined by the imbibition curve) and methods of removing the coat of kale seeds (total removal of the seed coat; cut in the distal region to the embryonic axis; longitudinal cut along the longest axis and whole seeds). Subsequently, the most efficient methodologies were evaluated using different concentrations of the tetrazolium salt solution (0.075%; 0.2%; 0.5% and 1.0%) and times (2, 4 and 6 h) of seed immersion in the solution, using four lots. The seeds were analyzed individually and classified as viable or non-viable. The tetrazolium test is efficient for evaluating the viability of kale seeds, providing results correlated with germination. Kale seeds should be primed between paper for 10 hours at 20 °C, and the seed coat should be removed for immersion in a 0.5% tetrazolium salt solution for 4 hours at 30 °C.

Resumo O objetivo deste trabalho foi estimar o número ótimo de colheitas para a seleção confiável de híbridos de abobrinha-italiana (Cucurbita pepo) por meio do coeficiente de repetibilidade. O delineamento experimental foi em blocos ao acaso, com 33 tratamentos (31 híbridos experimentais e 2 comerciais) e quatro repetições, com seis plantas por parcela. Realizaramse 15 colheitas. Sete características morfoagronômicas dos frutos foram avaliadas, e os coeficientes de repetibilidade foram estimados por meio de quatro métodos estatísticos. Os coeficientes de repetibilidade variaram de baixos a moderados, independentemente da característica estudada. Para uma seleção de alta precisão (R2≥90%), um elevado número de colheitas avaliadas foi necessário, especialmente para as características relacionadas à produtividade de frutos, conforme a seguir: 30 a 54 colheitas para a seleção baseada na produtividade total; e 43 a 83 colheitas para a0 produtividade comercial, que variou conforme o método estatístico de estimação. A análise de componentes principais baseada na matriz de covariância demandou a menor quantidade de colheitas para uma precisão satisfatória da seleção. São suficientes 15 colheitas para a seleção satisfatória de todas as características avaliadas, com precisão superior a 70%.

Abstract The objective of this work was to estimate the optimal number of harvests for the reliable selection of zucchini (Cucurbita pepo) hybrids through the repeatability coefficient. The experimental design was randomized complete blocks with 33 treatments (31 experimental hybrids and 2 commercial ones) and four replicates, with six plants per plot. Fifteen harvests were carried out. Seven morphoagronomic fruit characteristics were evaluated, and repeatability coefficients were estimated using four statistical methods. The repeatability coefficients ranged from low to moderate, regardless of the studied characteristic. For a high-precision selection (R2≥90%), a high number of evaluated harvests was required, especially for traits related to fruit yield, as follows: 30 to 54 harvests for selection based on total yield; and 43 to 83 harvests for commercial yield, which varied according to the statistical estimation method. The principal component analysis based on the covariance matrix required the least number of harvests for a satisfactory selection precision. Fifteen harvests are sufficient for a satisfactory selection of all evaluated characteristics, with a precision above 70%.

Resumo: Para que a germinação das sementes de batata-doce (Ipomoea batatas) ocorra, é necessária a superação da dormência, o que dificulta a avaliação do potencial fisiológico das sementes. Objetivou-se nesta pesquisa definir metodologia para superação da dormência de sementes de batata-doce e o uso da análise de imagens para determinar a qualidade física e fisiológica das sementes. Foram utilizados quatro genótipos de sementes de batata-doce, UFVJM-5, UFVJM-22, UFVJM-38 e UFVJM-65. Para a superação da dormência foi testado a escarificação química com H2SO4 a 98% por 10 e 20 minutos, água quente a 95 °C por 10 e 20 minutos e escarificação mecânica com esmeril elétrico. Para avaliação da qualidade física, as sementes foram analisadas com raios X e classificadas em sementes cheias, vazias e malformadas. Por meio do sistema GroundEye®, foram quantificadas as características de dominâncias de cor, de geometria das sementes e comprimento de plântulas. Os tratamentos com escarificação mecânica com esmeril e ácido sulfúrico a 98%, pelo período de imersão de 20 minutos, são eficientes para a superação de dormência em sementes de batata-doce. Existem divergências genéticas entre os genótipos de batata-doce, promovendo a formação de grupos diferentes. As características de cor e geometria das sementes são as que mais contribuem para diversidade genética dos genótipos.

Abstract: For the germination of sweet potato (Ipomoea batatas) seeds to occur, it is necessary to overcome dormancy, which makes it difficult to assess their physiological potential. The aim of this research was to define a methodology to overcome the dormancy of sweet potato seeds and use image analysis to determine their physical and physiological quality. Four genotypes of sweet potato seeds were used, namely UFVJM-5, UFVJM-22, UFVJM-38 and UFVJM-65. To overcome dormancy, chemical scarification with 98% H2SO4 for 10 and 20 minutes, hot water at 95 °C for 10 and 20 minutes, and mechanical scarification with electric grinder were tested. To evaluate the physical quality, the seeds were analyzed with X-rays and classified as intact, empty and malformed seeds. Using the GroundEye® system, the characteristics of color dominance, seed geometry and seedling length were quantified. Treatments with mechanical scarification with grinder and 98% sulfuric acid, for an immersion period of 20 minutes, are efficient to break dormancy in sweet potato seeds. There are genetic divergences between sweet potato genotypes, promoting the formation of different groups. The characteristics of color and geometry of the seeds are the ones that most contribute to genetic diversity of genotypes.

ABSTRACT The growing consumer demand for sweet potato roots results in the need for genotypes with higher yields and better root quality. Thus, the objective of this study was to agronomically evaluate sweet potato genotypes via mixed models to select superior genotypes for human consumption and predict their selection gains. The study had a partially balanced triple lattice design with three replicates. As treatments, 92 sweet potato genotypes from the Universidade Federal de Lavras germplasm bank selected in the first selection cycle were evaluated along with eight controls, namely, Brazlândia Roxa, Princesa, Uruguaiana, BRS Amélia, Beauregard, UFVJM-57, UFVJM-58, and UFVJM-61. The treatments were ranked by the mixed linear model via restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP). We highlighted the 15 best genotypes for each agronomic trait, then identified the best ones overall considering all quantitative and qualitative traits. High heritability was found for the trait commercial root yield (56.31%). For all traits, there were selection gains relative to the population mean. The use of mixed models was efficient for the selection of superior sweet potato genotypes. The genotypes 2018-19-464, 2018-72-1409, 2018-72-1428, 2018-19-443, 2018-36-807, 2018-72-1418, 2018-19-455, 2018-72-1376, 2018-54-1137, 2018-54-1114, 2018-65-1249, and 2018-28-556 have good traits related to commercial root yield and root quality and may be recommended for human consumption.

Irrigated agriculture has become a concern, given the scarcity of freshwater. To reduce its water consumption, new techniques and technologies have been proposed. Based on this, the objective of this work was to evaluate the influence of different soil water tensions at initiation of irrigation with magnetically treated water, on 'iceberg' lettuce Lucy Brown (Lactuca Sativa L.) development and production. The experiment was conducted in a greenhouse, using a completely randomized factorial design, to evaluate two water types (magnetically treated water - MW and ordinary water - OW) and four soil water tensions at initiation of irrigation (T1 - 15 kPa, T2 - 25 kPa, T3 - 40 kPa and T4 - 70 kPa), with three replicates. Tensiometers were used to estimate soil water tension. The evaluated parameters were: aerial part fresh and dry total mass; commercial head fresh and dry mass, root fresh and dry mass; stem fresh and dry mass; stem length and diameter; percentage of leaves with tip burn, total and commercial yield; water use efficiency related to total and commercial yield; plant exposed area; and dry matter content. Despite achieving greater water use efficiency, the magnetic treatment may have hindered the removal of water from the soil by the crop, especially at increased soil water tension at initiation of irrigation.

ABSTRACT Starch is the most natural polymer used in the food and non-food industry. Sweet potato is among the world’s most important, versatile and underexploited food crops; its composition depends on the planting strategy, climatic conditions, cultivar, geographic region, soil quality, and other. The physical-chemical characteristic and functional properties depends also of the amylose, amylopectin ratio and the molecular components of amylose and amylopectin. In this study, the structural and physicochemical properties of starches from four sweet potato genotypes cultivated in Brazil were compared. Starch granules of roots of sweet potato all exhibited oval and irregular shapes with granule sizes ranging from 8 to 30 µm. Amylose contents of roots of sweet potato starches differed from 9.7 to 15.1%. Ratios of 1045/1022 and 1022/995 cm-1 of Fourier transform infrared spectra varied in the range of 0.8114–0.8558 and 0.9046–0.9347, respectively, which means that the genotypes present different structure ordering. Also, the digestibility, swelling power, and solubility showed some differences between the starches, probably due to the differences in amylose and amylopectin contents and granules sizes. The different genotypes showed similar thermal stability. Our study indicated the sweet potato genotypes are greatly influenced the amylose content, structure order, the degree of short-range order, granule size, digestibility, swelling power and solubility of sweet potato genotypes.

Resumo Ramas de batata-doce apresentam características satisfatórias para alimentação animal, porém não têm sido exploradas na forma de feno. Objetivou-se avaliar o uso de ramas de batata-doce para a produção de feno e a divergência genética em clones de batata-doce. Foram avaliados dez clones de batata-doce, conduzidos a campo em blocos ao acaso e cinco repetições. Foram determinados o teor de matéria seca, as produtividades de massa verde e massa seca (PMS), a relação folha e haste das ramas e a produção total e comercial de raízes (PRC). Obtidos os fenos, avaliaram-se as características MS, PB, FDN, FDA, lignina, amido, açúcares solúveis, macro e micronutrientes. Estimou-se a divergência genética entre os clones de batata-doce. O clone UFVJM-54 aliou alta PRC com maior PMS. Os fenos apresentaram teores de PB variando de 11,99 a 15,09%, FDN 47,22 a 55,55%, FDA 22,92 a 28%, e 6,87 a 13,72% de LIG. De forma geral, os teores de minerais nos fenos foram satisfatórios. Os clones foram separados em cinco grupos diferentes. As ramas de batata-doce podem ser utilizadas para a produção de feno. Os clones UFVJM-37, UFVJM-46 e UFVJM-54 são recomendados para cruzamentos com os demais genótipos.

Abstract Sweet potato branches have satisfactory characteristics for animal feed, but have not been exploited in the form of hay. The objective of this work was to evaluate the use of the sweet potato branches for the hay production and genetic divergence in sweet potato clones. Were evaluated ten sweet potato clones, conducted on the field in randomized blocks and 5 repetitions. Dry matter content, green mass and dry mass yield (DMY), leaf and stem ratio of branches and total and commercial root production (CRP) were determined. Gotten the hays, were evaluated the characteristics: DM, CP, NDF, ADF, lignin, starch, soluble sugars, macro and micronutrients. The genetic divergence among the sweet potato clones was estimated. The UFVJM-54 clone allied high CRP with bigger DMY. The hay presented content of CP ranging from 11.99% to 15.09%, NFD 47.22 to 55.55%, ADF 22.92 to 28%, and 6.87 to 13.72% of LIG. In a general way, the contents of minerals in hays were satisfactory. The clones were separated into 5 different groups. The sweet potato branches can be used for the hay production. The UFVJM-37, UFVJM-46 and UFVJM-54 clones are recommended for crossing with the other genotypes.

RESUMO As ramas de batata-doce apresentam potencial de utilização na alimentação animal, na forma fresca e de silagem, sendo que a utilização de aditivos pode contribuir para a melhoria da qualidade da silagem das ramas. Objetivou-se com este estudo avaliar a qualidade da silagem de ramas de batata-doce com diferentes aditivos. Os tratamentos utilizados para a confecção das silagens foram: ramas puras; ramas + 10% de MDPS (milho desintegrado com palha e sabugo); ramas + 10% de bagaço de cana de alambique; ramas + 10% de polpa cítrica; ramas + 10% de casca de café. Foram determinadas amatéria seca, proteína bruta, fibra de detergente neutro (FDN), fibra de detergente ácido (FDA), celulose, hemicelulose, lignina, cinzas, amido, açucares solúvel, pH, população de Bactérias do ácido láctico, perdas por gases e efluentes. As silagens de ramas + MDPS, ramas + polpa cítrica e ramas + casca de café apresentaram os maiores teores de matéria seca. Na silagem de ramas + polpa cítrica foi registrada alto teor de FDN. Já na silagem de ramas + MDPS obteve-se o menor teor de FDA. O teor de lignina foi baixo nas silagens das ramas + MDPS, ramas puras e ramas + polpa cítrica. Os teores de amido, PB e populações de BAL foram adequados para todas as silagens. A silagem contendo ramas + MDPS apresentou os melhores resultados para as características avaliadas, de forma que o aditivo utilizado nesta silagem é o mais recomendado para as condições experimentadas.

ABSTRACT Sweet potato branches have potential use in animal feeding, even fresh or ensiled, and some additives may enhance their quality. This study aimed at assessing silage quality of sweet potato branches using different additives. We ensiled sweet potato branches without additive (control) and with the addition of 10% disintegrated corn with straw and corncob (DCSC), 10% sugarcane bagasse from alembic, 10% citrus pulp, and 10% coffee husk. Three samples of each plot were obtained after drying for measurements of dry matter, crude protein, neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose, hemicellulose, lignin, mineral matter, starch, soluble sugars, pH, lactic acid bacteria population, gas, and effluent losses. Silage with DCSC, citrus pulp, and coffee rusk reached the highest dry matter contents. Moreover, citrus pulp silage had a high content of NDF. In contrast, DCSC silage showed the lowest content of ADF. Lignin was low in silage with DCSC, citrus pulp, and control (without additive). Suitable amounts of starch, crude protein, and lactic acid bacteria population were found in all treatments. Silage with DCSC achieved the best results for the assessed variables. Therefore, DCSC is the most suitable additive to improve silage quality of sweet potato branches.

ABSTRACT. The aim of this study was to obtain information for the genetic improvement of kale through repeatability and phenotypic stabilization studies and to compare methodologies that represent the reliability of the estimated parameters. Thirty-three half-sib progenies were evaluated in a randomized block design with three replicates and six plants per plot. Eight harvests were evaluated in terms of the yield of fresh leaves, number of shoots, number of leaves and average mass of leaves. Then, a phenotypic repeatability and stabilization study was performed, estimating the genetic parameters σ2a, σ²g, σ²e, and the coefficient of environmental variation and repeatability using the frequentist and Bayesian methodologies. To evaluate the reliability of these estimates, intervals were obtained using the frequentist, Bayesian and bootstrap methods. It was verified that the reliable selection of progenies of half-sib of kale can be achieved in four harvests that were realized between 95 and 170 days after planting. It was observed that the frequentist and Bayesian methodologies are better suited to obtain reliable estimates of the genetic parameters evaluated, as the last one provided smaller amplitudes for the obtained intervals. The bootstrap methodologies are not recommended for phenotypic repeatability and stabilization studies in kale.

RESUMO Devido ao balanço hídrico no cerrado brasileiro não permitir cultivo de rúcula em sistema de sequeiro, aliado à inexistência de trabalhos de pesquisa com esta olerícola, cria-se a necessidade de estudar a resposta de genótipos à irrigação neste bioma. Assim, objetivou-se determinar a lâmina ótima de irrigação e identificar os melhores genótipos de rúcula. Três genótipos de rúcula foram testados em campo, durante dois ciclos, sob o efeito de quatro lâminas de irrigação, baseado na evapotranspiração da cultura. Os parâmetros avaliados foram: profundidade de raízes, teor de clorofila foliar, número de plantas e de folhas por planta, diâmetro de planta, massa fresca da parte aérea e eficiência do uso da água. A rúcula apresentou a mesma demanda por irrigação nos dois ciclos e os genótipos e/ou lâminas de irrigações conferiram efeito nos parâmetros avaliados. Os resultados subsidiam que a rúcula Folha Larga deve ser preferida pelos produtores do cerrado brasileiro e irrigada com reposição de 90% da evapotranspiração da cultura.

ABSTRACT Due to the water balance in the Brazilian Cerrado, it is not necessary to cultivate arugula in a rainfed system. Together with the lack of research on with this crop, it is necessary to study the response of genotypes to irrigation in this biome. Thus, the objective of this study was to determine the optimal irrigation depth and to identify the best arugula genotypes. Three arugula genotypes were field-tested during two cycles under the effect of four irrigation depths based on crop evapotranspiration. The parameters evaluated were root depth, SPAD index, number of plants and leaves per plant, plant diameter, fresh shoot mass and water use efficiency. The arugula presented the same demand for irrigation in the two cycles, and the genotypes and/or irrigation depths affected the evaluated parameters. The results support that the Folha Larga variety should be preferred by Brazilian Cerrado producers and irrigated with 90% replacement of crop evapotranspiration.

RESUMO O cultivo de batata-doce é promissor no Brasil em função do seu potencial para produção de bioenergia. Porém, são escassas informações acerca da adequacão do controle químico de plantas daninhas na cultura. Objetivou-se avaliar o uso de clomazone no cultivo de 20 genótipos de batata-doce e a sensibilidade dos materiais à interferência de plantas daninhas. Para isso, em condições de campo, foi delineado um experimento em quatro blocos e esquematizado em parcelas subdivididas. Os genótipos Brazlândia Branca, Cariru Vermelha, Princesa, Tomba Carro1 e UFVJM (01, 05, 06 , 07, 08, 10, 14, 23, 26, 30, 35, 42, 43, 46, 48 e 49) foram cultivados por 180 dias em solo tratado com clomazone, capinado mecanicamente ou sem o controle de plantas daninhas. As formas de controle compunham as parcelas, e os genótipos foram alocados nas subparcelas. Foi avaliada a fitointoxicação, o crescimento de ramas e a produtividade. Foi observado maior comprimento de ramas quando as plantas cresceram sem a interferencia das plantas daninhas. As maiores produtividades foram conseguidas em solo tratado com clomazone e a interferência de plantas daninhas provocou reduções de 81 a 99,7% na produtividade. Os genótipos menos sensíveis à interferência de plantas daninhas foram UFVJM07, UFVJM10 e UFVJM35, enquanto os mais sensíveis foram Princesa e UFVJM01. O controle químico proporcionou produtividade de raízes semelhante ou superior ao controle mecânico para 17 dos 20 genótipos estudados.

ABSTRACT Sweet potato is a promising crop in Brazil due to its potential for bioenergy production. However, little information on adequate chemical weed control is found for this crop. Thus, the objective of this work was to evaluate the effect of clomazone on 20 genotypes of sweet potato and the sensitivity of these materials to weed interference. A field experiment was conducted using an experimental design with four blocks arranged in split-plots. The sweet potato genotypes Brazlândia-Branca, Cariru-Vermelha, Princesa, Tomba-Carro-1 and UFVJM (01, 05, 06, 07, 08, 10, 14, 23, 26, 30, 35, 42, 43, 46, 48 and 49) were grown for 180 days under three weed managements (soils treated with clomazone, mechanically weeded and with no weed control). The plots consisted of the weed control methods and the subplots consisted of the sweet potato genotypes. Phytotoxicity, branch growth and yield were evaluated. Plants grown with no weed interference had larger branch length. The highest yields were found in clomazone-treated soils. Weed interference reduced 81 to 99.7% of the yield. The less susceptible genotypes to weed interference were UFVJM07, UFVJM10 and UFVJM35, and the most sensitive were Princesa and UFVJM01. The root yield of plants under chemical weed control was similar to or greater than those with mechanical weed control in 17 of the 20 genotypes evaluated.

RESUMO. Objetivou-se avaliar a dissimilaridade genética entre genótipos de batata-doce por meio de descritores morfológicas e moleculares. O experimento foi conduzido no Setor de Olericultura da Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM) avaliando-se 60 genótipos de batata-doce. Na caracterização morfológica, utilizaram-se 24 descritores. Na caracterização molecular, utilizaram-se onze primers microssatélites específicos para batata-doce, obtendo-se 210 bandas polimórficas. A diversidade morfológica e molecular foi obtida por matrizes de dissimilaridade baseando-se no coeficiente de coincidência simples e índice de Jaccard, para dados morfológicos e moleculares, respectivamente. A partir destas matrizes foram construídos dendrogramas. Houve grande variabilidade genética entre os genótipos de batata doce do banco de germoplasma da UFVJM, tanto pela caracterização molecular como morfológica. Não houve suspeita de duplicata nem associação entre a análise molécular e morfológica. Foram identificados acessos divergentes pelas análises moleculares e morfológicas, os quais são indicados como genitores para compor programas de melhoramento a fim de obter progênies com alta variabilidade genética.

ABSTRACT. This study aimed to evaluate the genetic dissimilarity among sweet potato genotypes using morphological and molecular descriptors. The experiment was conducted in the Olericulture Sector at Federal University of Jequitinhonha and Mucuri Valleys (UFVJM) and evaluated 60 sweet potato genotypes. For morphological characterization, 24 descriptors were used. For molecular characterization, 11 microsatellite primers specific for sweet potatoes were used, obtaining 210 polymorphic bands. Morphological and molecular diversity was obtained by dissimilarity matrices based on the coefficient of simple matching and the Jaccard index for morphological and molecular data, respectively. From these matrices, dendrograms were built. There is a large amount of genetic variability among sweet potato genotypes of the germplasm bank at UFVJM based on morphological and molecular characterizations. There was no duplicate suspicion or strong association between morphological and molecular analyses. Divergent accessions have been identified by molecular and morphological analyses, which can be used as parents in breeding programmes to produce progenies with high genetic variability.