Cassava Frogskin Disease: Current Knowledge on a Re-Emerging Disease in the Americas.

Cassava frogskin disease (CFSD) is a graft-transmissible disease of cassava reported for the first time in the 1970s, in Colombia. The disease is characterized by the formation of longitudinal lip-like fissures on the peel of the cassava storage roots and a progressive reduction in fresh weight and starch content. Since its first report, different pathogens have been identified in CFSD-affected plants and improved sequencing technologies have unraveled complex mixed infections building up in plants with severe root symptoms. The re-emergence of the disease in Colombia during 2019-2020 is again threatening the food security of low-income farmers and the growing local cassava starch industry. Here, we review some results obtained over several years of CFSD pathology research at CIAT, and provide insights on the biology of the disease coming from works on symptoms' characterization, associated pathogens, means of transmission, carbohydrate accumulation, and management. We expect this work will contribute to a better understanding of the disease, which will reflect on lowering its impact in the Americas and minimize the risk of its spread elsewhere.

Desempenho agronômico de mandioca de mesa manejada com irrigação e uso de cobertura plástica do solo / Agronomic performance of sweet cassava managed with irrigation and use of plastic soil cover

Apesar da mandioca ser reconhecida pela sua elevada tolerância à seca, a irrigação vem apresentando resultados satisfatórios. Entretanto, poucos estudos vêm sendo desenvolvidos visando a determinação dos efeitos da cobertura do solo, da irrigação e da combinação de ambos no desenvolvimento da cultura. O objetivo deste estudo foi determinar a influência da irrigação e da cobertura plástica do solo, no desempenho agronômico de mandioca de mesa. O plantio foi feito em canteiros, no sistema de fileira dupla com as manivas-sementes implantadas na vertical em espaçamento de 0,60 m entre linhas e 0,80 m entre plantas. Foram aplicados os tratamentos canteiro desnudo sem irrigação, canteiro coberto com plástico de polietileno preto sem irrigação, canteiro desnudo com irrigação e canteiro coberto com plástico de polietileno preto com irrigação. As irrigações foram por aspersão convencional, com base no balanço diário de água do solo na profundidade efetiva do sistema radicular da mandioca nos diferentes estágios de desenvolvimento da cultura. Os caracteres avaliados em duas safras foram: produtividade de parte aérea, produtividade de raízes, porcentagem de amido nas raízes e tempo para a cocção. A expressão dos caracteres produtividade de raízes, peso da parte aérea e teor de amido nas raízes, foi influenciada pelo manejo da irrigação e pela cobertura do solo. A utilização individual das tecnologias de irrigação e de cobertura plástica do solo, proporcionaram aumentos de produtividade de raízes de 55% e 13%, respectivamente, e quando foram utilizadas em conjunto a produtividade de raízes aumentou 89%.(AU)

Although cassava is recognized for its high tolerance to drought, irrigation is showing satisfactory results. However, few studies have been carried out to determine the effects of soil cover, irrigation and the combination of both on crop development. The objective of this study was to determine the influence of irrigation and plastic soil cover on the agronomic performance of sweet cassava. The planting was done in beds, in the double row system with the stem cutings implanted vertically, with 0.60 m between rows and 0.80 m between plants. The following treatments were applied: naked non-irrigated bedding, bedding covered with non-irrigated black polyethylene plastic, naked bedding with irrigation and bedding covered with irrigated black polyethylene plastic. Irrigation was performed by conventional sprinkling, based on the daily soil water balance at the effective depth of the cassava root system in the different stages of crop development. The characters evaluated were: shoot weight, root yield, starch percentage in the roots and time for cooking. The expression of the characters shoot weight, root yield and starch percentage in the roots was significantly influenced by irrigation management and soil cover. The individual use of irrigation and plastic soil cover technologies led to increases in root yield of 55% and 13%, respectively, and when used together, root yield increased by 89%.(AU)

Desempenho agronômico de mandioca de mesa manejada com irrigação e uso de cobertura plástica do solo / Agronomic performance of sweet cassava managed with irrigation and use of plastic soil cover

Apesar da mandioca ser reconhecida pela sua elevada tolerância à seca, a irrigação vem apresentando resultados satisfatórios. Entretanto, poucos estudos vêm sendo desenvolvidos visando a determinação dos efeitos da cobertura do solo, da irrigação e da combinação de ambos no desenvolvimento da cultura. O objetivo deste estudo foi determinar a influência da irrigação e da cobertura plástica do solo, no desempenho agronômico de mandioca de mesa. O plantio foi feito em canteiros, no sistema de fileira dupla com as manivas-sementes implantadas na vertical em espaçamento de 0,60 m entre linhas e 0,80 m entre plantas. Foram aplicados os tratamentos canteiro desnudo sem irrigação, canteiro coberto com plástico de polietileno preto sem irrigação, canteiro desnudo com irrigação e canteiro coberto com plástico de polietileno preto com irrigação. As irrigações foram por aspersão convencional, com base no balanço diário de água do solo na profundidade efetiva do sistema radicular da mandioca nos diferentes estágios de desenvolvimento da cultura. Os caracteres avaliados em duas safras foram: produtividade de parte aérea, produtividade de raízes, porcentagem de amido nas raízes e tempo para a cocção. A expressão dos caracteres produtividade de raízes, peso da parte aérea e teor de amido nas raízes, foi influenciada pelo manejo da irrigação e pela cobertura do solo. A utilização individual das tecnologias de irrigação e de cobertura plástica do solo, proporcionaram aumentos de produtividade de raízes de 55% e 13%, respectivamente, e quando foram utilizadas em conjunto a produtividade de raízes aumentou 89%.

Although cassava is recognized for its high tolerance to drought, irrigation is showing satisfactory results. However, few studies have been carried out to determine the effects of soil cover, irrigation and the combination of both on crop development. The objective of this study was to determine the influence of irrigation and plastic soil cover on the agronomic performance of sweet cassava. The planting was done in beds, in the double row system with the stem cutings implanted vertically, with 0.60 m between rows and 0.80 m between plants. The following treatments were applied: naked non-irrigated bedding, bedding covered with non-irrigated black polyethylene plastic, naked bedding with irrigation and bedding covered with irrigated black polyethylene plastic. Irrigation was performed by conventional sprinkling, based on the daily soil water balance at the effective depth of the cassava root system in the different stages of crop development. The characters evaluated were: shoot weight, root yield, starch percentage in the roots and time for cooking. The expression of the characters shoot weight, root yield and starch percentage in the roots was significantly influenced by irrigation management and soil cover. The individual use of irrigation and plastic soil cover technologies led to increases in root yield of 55% and 13%, respectively, and when used together, root yield increased by 89%.

Machine learning for high-throughput field phenotyping and image processing provides insight into the association of above and below-ground traits in cassava (Manihot esculenta Crantz).

BACKGROUND: Rapid non-destructive measurements to predict cassava root yield over the full growing season through large numbers of germplasm and multiple environments is a huge challenge in Cassava breeding programs. As opposed to waiting until the harvest season, multispectral imagery using unmanned aerial vehicles (UAV) are capable of measuring the canopy metrics and vegetation indices (VIs) traits at different time points of the growth cycle. This resourceful time series aerial image processing with appropriate analytical framework is very important for the automatic extraction of phenotypic features from the image data. Many studies have demonstrated the usefulness of advanced remote sensing technologies coupled with machine learning (ML) approaches for accurate prediction of valuable crop traits. Until now, Cassava has received little to no attention in aerial image-based phenotyping and ML model testing. RESULTS: To accelerate image processing, an automated image-analysis framework called CIAT Pheno-i was developed to extract plot level vegetation indices/canopy metrics. Multiple linear regression models were constructed at different key growth stages of cassava, using ground-truth data and vegetation indices obtained from a multispectral sensor. Henceforth, the spectral indices/features were combined to develop models and predict cassava root yield using different Machine learning techniques. Our results showed that (1) Developed CIAT pheno-i image analysis framework was found to be easier and more rapid than manual methods. (2) The correlation analysis of four phenological stages of cassava revealed that elongation (EL) and late bulking (LBK) were the most useful stages to estimate above-ground biomass (AGB), below-ground biomass (BGB) and canopy height (CH). (3) The multi-temporal analysis revealed that cumulative image feature information of EL + early bulky (EBK) stages showed a higher significant correlation (r = 0.77) for Green Normalized Difference Vegetation indices (GNDVI) with BGB than individual time points. Canopy height measured on the ground correlated well with UAV (CHuav)-based measurements (r = 0.92) at late bulking (LBK) stage. Among different image features, normalized difference red edge index (NDRE) data were found to be consistently highly correlated (r = 0.65 to 0.84) with AGB at LBK stage. (4) Among the four ML algorithms used in this study, k-Nearest Neighbours (kNN), Random Forest (RF) and Support Vector Machine (SVM) showed the best performance for root yield prediction with the highest accuracy of R2 = 0.67, 0.66 and 0.64, respectively. CONCLUSION: UAV platforms, time series image acquisition, automated image analytical framework (CIAT Pheno-i), and key vegetation indices (VIs) to estimate phenotyping traits and root yield described in this work have great potential for use as a selection tool in the modern cassava breeding programs around the world to accelerate germplasm and varietal selection. The image analysis software (CIAT Pheno-i) developed from this study can be widely applicable to any other crop to extract phenotypic information rapidly.

Agronomic performance of cassava genotypes from the in vitro shoot tip culture submitted to clonal cleaning / Desempenho agronômico de genótipos de mandioca provenientes do cultivo in vitro de ápices caulinares submetidos à limpeza clonal

This study aimed to evaluate the agronomic performance of cassava genotypes from the in vitro shoot tip culture to eliminate the cassava frogskin disease for several root and aerial part characteristics. Cassava plants from accessions BGM0315, BGM0464 and BGM0841 infected with cassava frogskin disease were grown in a greenhouse after clonal cleaning. Cuttings from the three accessions were subjected to tetracycline concentrations (0, 5, 10 and 15 mg L-1) for three minutes, and then maintained in an acclimatized chamber (35 ± 1 °C and 16 hour photoperiod). Shoots were disinfected for excising shoot tips (0.2 mm and 0.4 mm) and inoculated in a culture medium containing the same concentrations of tetracycline used in the cuttings. After 60 days of cultivation, the explants were transferred to medium without antibiotic, 30 days later they were acclimatized for a period of 70 days for subsequent planting in the field. Seven months after planting, agronomical evaluation was held for root and aerial part characteristics. No influence of isolated shoot tip size was noticed on agronomic characteristics, while the addition of tetracycline in the culture medium, specifically at the concentrations of 5 mg L-1 and 15 mg L-1, was favorable to the development of the root system of plants in the field. The results revealed that the agronomic performance of cassava plants derived from in vitro cultivation are higher for the production of basic propagation material for the following production cycles, as well as root production for commercial use with subsequent generation of income.

Este trabalho teve por objetivo avaliar o desempenho agronômico de genótipos de mandioca provenientes do cultivo in vitro de ápices caulinares para eliminação da doença couro de sapo (Cassava frogskin disease, CFSD), em relação a diversas características de raiz e da parte aérea. Para isso, foram utilizadas plantas de mandioca dos acessos BGM0315, BGM0464 e BGM0841 cultivadas em casa de vegetação após a limpeza clonal. Inicialmente, foram utilizadas manivas de plantas adultas infectadas com couro de sapo. Essas manivas foram submetidas a concentrações de tetraciclina (0, 5, 10 e 15 mg L-1) por 3 minutos. Posteriormente, foram mantidas em câmara climatizada (35 ± 1°C e fotoperíodo de 16 horas). Brotos foram desinfestados para excisão de ápices caulinares (0,2 mm e 0,4 mm) e inoculados em meio de cultura contendo as mesmas concentrações de tetraciclina empregadas nas manivas. Aos 60 dias de cultivo, os explantes foram transferidos para meio sem antibiótico, 30 dias após foram aclimatizadas por um período de 70 dias para posterior plantio em campo. Aos sete meses após o plantio realizou-se a avaliação agronômica para características de raiz e parte aérea. Não houve influência do tamanho do ápice caulinar isoladamente nas características agronômicas avaliadas, enquanto que a adição de tetraciclina no meio de cultura, especificamente nas concentrações de 5 e 15 mg L-1, foi favorável ao desenvolvimento do sistema radicular das plantas no campo. Os resultados evidenciaram que o desempenho agronômico de plantas de mandioca provenientes do cultivo in vitro são elevados para produção de material propagativo básico para os ciclos seguintes de produção, bem como para produção de raízes para uso comercial com consequente geração de renda.

Nitrogênio no crescimento da planta e na qualidade de raízes da mandioquinha-salsa / Nitrogen on plant growth and storage root quality of Arracacha

RESUMO: O nitrogênio (N) é o segundo nutriente mais absorvido pela mandioquinha-salsa. No entanto, ainda existem dúvidas sobre a influência que esse nutriente pode exercer sobre o crescimento da planta e a qualidade das raízes de reserva. Assim, objetivou-se com este trabalho avaliar a influência da adubação nitrogenada no crescimento da planta e na qualidade físico-química e nutricional das raízes de mandioquinha-salsa. O experimento foi conduzido em um Latossolo Vermelho distrófico de textura arenosa, no delineamento experimental de blocos ao acaso, com quatro repetições. Os tratamentos foram constituídos pelas doses de 0, 50, 100 e 200kg ha-1 de N. O crescimento das partes vegetativas da planta de mandioquinha-salsa aumentou linearmente com a adubação nitrogenada, mas a massa média e a produtividade das raízes de reserva aumentaram até as doses estimadas de 121 e 148kg ha-1 de N, respectivamente. A adubação nitrogenada aumentou os teores de amido e de proteína das raízes e diminuiu os teores de açúcares totais, porém, sem influenciar a qualidade nutricional delas.

ABSTRACT: Nitrogen (N) is the second most absorbed nutrient by Arracacha. However, there are still doubts about the influence that this nutrient can have on plant growth and the quality of the storage roots. Thus, the aim of this research was to evaluate the influence of nitrogen fertilization on plant growth and physical-chemical and nutritional quality of storage roots of Arracacha. The experiment was conducted on an Oxisol of sandy texture, in a randomized complete block design, with four replications. The treatments consisted of rates of 0, 50, 100, and 200kg ha-1 N. Growth of vegetative parts of Arracacha increased linearly with nitrogen fertilization, but the storage root mean weight and the yield of storage roots increased up to estimated rates of 121 and 148kg ha-1 N, respectively. Nitrogen fertilization increased the starch and protein content of the storage roots and reduced the content of total sugar, but without affecting the nutritional quality of the same.

Nitrogen on plant growth and storage root quality of Arracacha / Nitrogênio no crescimento da planta e na qualidade de raízes da mandioquinha-salsa

Nitrogen (N) is the second most absorbed nutrient by Arracacha. However, there are still doubts about the influence that this nutrient can have on plant growth and the quality of the storage roots. Thus, the aim of this research was to evaluate the influence of nitrogen fertilization on plant growth and physical-chemical and nutritional quality of storage roots of Arracacha. The experiment was conducted on an Oxisol of sandy texture, in a randomized complete block design, with four replications. The treatments consisted of rates of 0, 50, 100, and 200kg ha-1 N. Growth of vegetative parts of Arracacha increased linearly with nitrogen fertilization, but the storage root mean weight and the yield of storage roots increased up to estimated rates of 121 and 148kg ha-1 N, respectively. Nitrogen fertilization increased the starch and protein content of the storage roots and reduced the content of total sugar, but without affecting the nutritional quality of the same.(AU)

O nitrogênio (N) é o segundo nutriente mais absorvido pela mandioquinha-salsa. No entanto, ainda existem dúvidas sobre a influência que esse nutriente pode exercer sobre o crescimento da planta e a qualidade das raízes de reserva. Assim, objetivou-se com este trabalho avaliar a influência da adubação nitrogenada no crescimento da planta e na qualidade físico-química e nutricional das raízes de mandioquinha-salsa. O experimento foi conduzido em um Latossolo Vermelho distrófico de textura arenosa, no delineamento experimental de blocos ao acaso, com quatro repetições. Os tratamentos foram constituídos pelas doses de 0, 50, 100 e 200kg ha-1 de N. O crescimento das partes vegetativas da planta de mandioquinha-salsa aumentou linearmente com a adubação nitrogenada, mas a massa média e a produtividade das raízes de reserva aumentaram até as doses estimadas de 121 e 148kg ha-1 de N, respectivamente. A adubação nitrogenada aumentou os teores de amido e de proteína das raízes e diminuiu os teores de açúcares totais, porém, sem influenciar a qualidade nutricional delas.(AU)

Nitrogen on plant growth and storage root quality of Arracacha / Nitrogênio no crescimento da planta e na qualidade de raízes da mandioquinha-salsa

Nitrogen (N) is the second most absorbed nutrient by Arracacha. However, there are still doubts about the influence that this nutrient can have on plant growth and the quality of the storage roots. Thus, the aim of this research was to evaluate the influence of nitrogen fertilization on plant growth and physical-chemical and nutritional quality of storage roots of Arracacha. The experiment was conducted on an Oxisol of sandy texture, in a randomized complete block design, with four replications. The treatments consisted of rates of 0, 50, 100, and 200kg ha-1 N. Growth of vegetative parts of Arracacha increased linearly with nitrogen fertilization, but the storage root mean weight and the yield of storage roots increased up to estimated rates of 121 and 148kg ha-1 N, respectively. Nitrogen fertilization increased the starch and protein content of the storage roots and reduced the content of total sugar, but without affecting the nutritional quality of the same.

O nitrogênio (N) é o segundo nutriente mais absorvido pela mandioquinha-salsa. No entanto, ainda existem dúvidas sobre a influência que esse nutriente pode exercer sobre o crescimento da planta e a qualidade das raízes de reserva. Assim, objetivou-se com este trabalho avaliar a influência da adubação nitrogenada no crescimento da planta e na qualidade físico-química e nutricional das raízes de mandioquinha-salsa. O experimento foi conduzido em um Latossolo Vermelho distrófico de textura arenosa, no delineamento experimental de blocos ao acaso, com quatro repetições. Os tratamentos foram constituídos pelas doses de 0, 50, 100 e 200kg ha-1 de N. O crescimento das partes vegetativas da planta de mandioquinha-salsa aumentou linearmente com a adubação nitrogenada, mas a massa média e a produtividade das raízes de reserva aumentaram até as doses estimadas de 121 e 148kg ha-1 de N, respectivamente. A adubação nitrogenada aumentou os teores de amido e de proteína das raízes e diminuiu os teores de açúcares totais, porém, sem influenciar a qualidade nutricional delas.

Nitrogênio no crescimento da planta e na qualidade de raízes da mandioquinha-salsa

ABSTRACT: Nitrogen (N) is the second most absorbed nutrient by Arracacha. However, there are still doubts about the influence that this nutrient can have on plant growth and the quality of the storage roots. Thus, the aim of this research was to evaluate the influence of nitrogen fertilization on plant growth and physical-chemical and nutritional quality of storage roots of Arracacha. The experiment was conducted on an Oxisol of sandy texture, in a randomized complete block design, with four replications. The treatments consisted of rates of 0, 50, 100, and 200kg ha-1 N. Growth of vegetative parts of Arracacha increased linearly with nitrogen fertilization, but the storage root mean weight and the yield of storage roots increased up to estimated rates of 121 and 148kg ha-1 N, respectively. Nitrogen fertilization increased the starch and protein content of the storage roots and reduced the content of total sugar, but without affecting the nutritional quality of the same.

RESUMO: O nitrogênio (N) é o segundo nutriente mais absorvido pela mandioquinha-salsa. No entanto, ainda existem dúvidas sobre a influência que esse nutriente pode exercer sobre o crescimento da planta e a qualidade das raízes de reserva. Assim, objetivou-se com este trabalho avaliar a influência da adubação nitrogenada no crescimento da planta e na qualidade físico-química e nutricional das raízes de mandioquinha-salsa. O experimento foi conduzido em um Latossolo Vermelho distrófico de textura arenosa, no delineamento experimental de blocos ao acaso, com quatro repetições. Os tratamentos foram constituídos pelas doses de 0, 50, 100 e 200kg ha-1 de N. O crescimento das partes vegetativas da planta de mandioquinha-salsa aumentou linearmente com a adubação nitrogenada, mas a massa média e a produtividade das raízes de reserva aumentaram até as doses estimadas de 121 e 148kg ha-1 de N, respectivamente. A adubação nitrogenada aumentou os teores de amido e de proteína das raízes e diminuiu os teores de açúcares totais, porém, sem influenciar a qualidade nutricional delas.

Crop losses in Brazilian cassava varieties induced by the Cassava common mosaic virus

Despite the widespread distribution of the Cassava common mosaic virus (CsCMV) in Brazil, little is known about the losses it causes in yield. The effect of CsCMV on different varieties was evaluated by reference to several agronomic traits. Four field trials were established in 2012/2013 and 2013/2014 using six varieties of cassava. Following mechanical inoculation with CsCMV, the presence of the virus was confirmed using the ELISA assay. The evaluated traits were plant height (PH), dry matter content (DMC), harvest index (HI), aerial part yield (APY), root yield (RoY), and starch yield (StY) in both inoculated and non-inoculated plants. Overall, the presence of the virus contributed little to the reduction in PH, HI, and DMC across the varieties, with PH being significantly reduced by 9.2 and 7.0 % in the BGM0212 and BRS Kiriris varieties, respectively. In contrast, APY, RoY, and StY were reduced by 30.2, 29.3, and 30.0 %, in the virus-infected plants respectively. While the BRS Kiriris and BRS Jari varieties suffered the highest reductions overall and were considered highly susceptible to CsCMV, none of the traits suffered reductions in the inoculated BRS Formosa plants. Although RoY and StY were reduced in inoculated plants of BRS Tapioqueira, crop yield for this variety was the highest. Thus, BRS Formosa and BRS Tapioqueira exhibited tolerance against CsCMV, which warrants further investigation.

Crop losses in Brazilian cassava varieties induced by the Cassava common mosaic virus

Despite the widespread distribution of the Cassava common mosaic virus (CsCMV) in Brazil, little is known about the losses it causes in yield. The effect of CsCMV on different varieties was evaluated by reference to several agronomic traits. Four field trials were established in 2012/2013 and 2013/2014 using six varieties of cassava. Following mechanical inoculation with CsCMV, the presence of the virus was confirmed using the ELISA assay. The evaluated traits were plant height (PH), dry matter content (DMC), harvest index (HI), aerial part yield (APY), root yield (RoY), and starch yield (StY) in both inoculated and non-inoculated plants. Overall, the presence of the virus contributed little to the reduction in PH, HI, and DMC across the varieties, with PH being significantly reduced by 9.2 and 7.0 % in the BGM0212 and BRS Kiriris varieties, respectively. In contrast, APY, RoY, and StY were reduced by 30.2, 29.3, and 30.0 %, in the virus-infected plants respectively. While the BRS Kiriris and BRS Jari varieties suffered the highest reductions overall and were considered highly susceptible to CsCMV, none of the traits suffered reductions in the inoculated BRS Formosa plants. Although RoY and StY were reduced in inoculated plants of BRS Tapioqueira, crop yield for this variety was the highest. Thus, BRS Formosa and BRS Tapioqueira exhibited tolerance against CsCMV, which warrants further investigation.(AU)

Performance of carrot genotypes at two Jequitinhonha Valley sites / Desempenho de cultivares de cenoura em duas regiões distintas do Alto Vale do Jequitinhonha, MG

The successful commercial use of carrot depends on the choice of cultivars that are well-adapted to soil and climate conditions at the cultivation site and on good consumer acceptance. The objective of this study was to evaluate the performance of carrot cultivars grown in autumn-winter in two towns with different climatic characteristics, in the High Jequitinhonha Valley, MG, Brazil. The experiments were conducted on the Rio Manso farm, in the town of Couto de Magalhães de Minas and on Campus JK at UFVJM, in the town of Diamantina, Minas Gerais, Brazil. Six carrot cultivars (Brasília, Nantes, Kuronan, Esplanada, Planalto and Tornado) were evaluated using a randomized complete block design with three replicates. The following morpho-agronomic characteristics were evaluated 100 days after sowing: shoot height, root length, root dry matter, total dry matter, harvest index, commercial yield and total yield root. The most suitable cultivars in Diamantina were Planalto, Tornado and Kuronan, and the cultivatar Planalto was the best suited to Couto de Magalhães de Minas. The agronomic performance of the cultivars was higher in Couto de Magalhães de Minas for the majority of the study variables, resulting in a higher total yield and commercial root yield. The climatic and soil conditions of Diamantina induced flowering in most cultivars, causing a loss to the commercial yield in autumn-winter cultivation.(AU)

O sucesso na exploração comercial da cenoura depende da escolha de cultivares com boa adaptação às condições de solo e de clima no local onde será cultivada e da boa aceitação pelo mercado consumidor. O objetivo do presente trabalho foi avaliar o desempenho de cultivares de cenoura no cultivo de outono-inverno em dois municípios com características edafoclimáticas distintas do Alto Vale do Jequitinhonha, MG. Os experimentos foram conduzidos na Fazenda Rio Manso, município de Couto de Magalhães de Minas, MG e no Campus JK da UFVJM, município de Diamantina, MG. Foram avaliadas seis cultivares de cenoura (Brasília, Nantes, Kuronan, Esplanada, Planalto e Tornado) utilizando-se o delineamento experimental em blocos ao acaso com três repetições. As características morfoagronomicas altura da parte aérea, comprimento de raiz, matéria seca de raiz, matéria seca total, índice de colheita, produtividade comercial e produtividade total de raízes foram avaliadas 100 dias após a semeadura. As cultivares que se destacaram em Diamantina foram Planalto, Tornado e Kuronan e em Couto de Magalhães de Minas a cultivar Planalto. O desempenho agronômico das cultivares foi superior em Couto de Magalhães de Minas para a maioria das variáveis avaliadas, resultando em uma maior produtividade total e comercial de raízes. As condições edafoclimáticas de Diamantina induzem florescimento na maioria das cultivares, causando perdas de produtividade comercial no cultivo deoutono-inverno.(AU)

Performance of carrot genotypes at two Jequitinhonha Valley sites / Desempenho de cultivares de cenoura em duas regiões distintas do Alto Vale do Jequitinhonha, MG

The successful commercial use of carrot depends on the choice of cultivars that are well-adapted to soil and climate conditions at the cultivation site and on good consumer acceptance. The objective of this study was to evaluate the performance of carrot cultivars grown in autumn-winter in two towns with different climatic characteristics, in the High Jequitinhonha Valley, MG, Brazil. The experiments were conducted on the Rio Manso farm, in the town of Couto de Magalhães de Minas and on Campus JK at UFVJM, in the town of Diamantina, Minas Gerais, Brazil. Six carrot cultivars (Brasília, Nantes, Kuronan, Esplanada, Planalto and Tornado) were evaluated using a randomized complete block design with three replicates. The following morpho-agronomic characteristics were evaluated 100 days after sowing: shoot height, root length, root dry matter, total dry matter, harvest index, commercial yield and total yield root. The most suitable cultivars in Diamantina were Planalto, Tornado and Kuronan, and the cultivatar Planalto was the best suited to Couto de Magalhães de Minas. The agronomic performance of the cultivars was higher in Couto de Magalhães de Minas for the majority of the study variables, resulting in a higher total yield and commercial root yield. The climatic and soil conditions of Diamantina induced flowering in most cultivars, causing a loss to the commercial yield in autumn-winter cultivation.

O sucesso na exploração comercial da cenoura depende da escolha de cultivares com boa adaptação às condições de solo e de clima no local onde será cultivada e da boa aceitação pelo mercado consumidor. O objetivo do presente trabalho foi avaliar o desempenho de cultivares de cenoura no cultivo de outono-inverno em dois municípios com características edafoclimáticas distintas do Alto Vale do Jequitinhonha, MG. Os experimentos foram conduzidos na Fazenda Rio Manso, município de Couto de Magalhães de Minas, MG e no Campus JK da UFVJM, município de Diamantina, MG. Foram avaliadas seis cultivares de cenoura (Brasília, Nantes, Kuronan, Esplanada, Planalto e Tornado) utilizando-se o delineamento experimental em blocos ao acaso com três repetições. As características morfoagronomicas altura da parte aérea, comprimento de raiz, matéria seca de raiz, matéria seca total, índice de colheita, produtividade comercial e produtividade total de raízes foram avaliadas 100 dias após a semeadura. As cultivares que se destacaram em Diamantina foram Planalto, Tornado e Kuronan e em Couto de Magalhães de Minas a cultivar Planalto. O desempenho agronômico das cultivares foi superior em Couto de Magalhães de Minas para a maioria das variáveis avaliadas, resultando em uma maior produtividade total e comercial de raízes. As condições edafoclimáticas de Diamantina induzem florescimento na maioria das cultivares, causando perdas de produtividade comercial no cultivo deoutono-inverno.

Prácticas agrícolas para el cultivo de Xanthium strumarium L (guizazo de caballo) con fines terapéuticos / Agricultural practices for the culture of Xanthium strumanium L (guizazo de caballo) with therapeutic aims

Xanthium strumarium (guizazo de caballo) se encuentra entre las plantas con antividad antimitótica. OBJETIVOS: determinar en esta especie los aspectos agrícolas que garanticen el adecuado material vegetal. MÉTODOS: se realizaron estudios durante 2007-2009, donde se evaluaron dos fechas de siembra: junio y julio; dos distancias de siembra 90 x 30 cm y 90 x 50 cm y dos momentos de cosecha: 3 meses de edad (parte aérea y raíces) en plantas que presentaban estado de floración-fructificación y 4 meses de edad (solo raíces) en plantas en fructificación. Las semillas, obtenidas de areales silvestres, se sembraron en parcelas, 3 repeticiones en cada caso. Se evaluó la altura de las plantas en el momento de la cosecha, se seleccionaron 10 plantas/parcelas y se cosecharon 39 plantas/parcelas en la distancia de 90 x 30 cm y 24 plantas en la distancia de 90 x 50 cm, en el caso del follaje se evaluaron los rendimientos de 10 plantas/parcelas en cada caso. RESULTADOS: se observó que bajo cultivo la altura de las plantas fueron mayores en las que se sembraron en junio, con distancia de 90 x 30 cm, en tanto que en las de julio se comportaron de forma similar, independientemente a las distancias de siembra empleadas y en correspondencia con ello los rendimientos resultaron iguales; sin embargo, cuando se quieren cosechar también las raíces, es preferible hacer la cosecha a los 3 meses de edad y, en este caso, los mayores valores se presentaron en las siembras de julio, con distancia de 90 x 30 cm. CONCLUSIÓN: para el aprovechamiento de la planta con doble propósito: parte aérea y raíces, pues en ambas se ha encontrado la actividad antimitótica, la siembra se debe realizar entre junio y julio a la distancia de 90 x 30 cm y recolectarse el material a la edad de 3 meses(AU)

Xanthium strumarium (guizazo de caballo) is among the plants with antimitotic activity. OBJECTIVES: to determine in this species the agricultural features to guarantee the appropriate plant material. METHODS: during 2007-2009 studies were conducted to assess to sow dates: June and July; two sow distances 90 x 30 cm and 90 x 50 cm at two sow periods: three months of age (aerial parts and roots) in plants with a flowering-fructification states and four months of age (only roots) in plants in fructification process. Seeds obtained from wild aerial plants were sowed in plots, three repetitions in each case. The plants height was assessed at the harvest moment, choosing 10 plants/lots and 39 plants/lots were growed at a 90 x 30 cm distance and 24 plants at the 90 x 50 cm distance, in the case of foliage the yields of 10 plants/lots were assessed in each case. RESULTS: there was that at culture the plants heights were higher in those sowed in June at a 90 x 30 cm distance while those sowed in July behaved in a similar way independently of the sow distances used and in correspondence with it, the yields were similar; however, when we desire to grow also the roots, it is preferable to grow at three months of age, and in this case, the higher values were in sows of July at a 90 x 30 cm distance. CONCLUSION: for the plant exploitation with a double aim: aerial parts and roots, since in both there is antimitotic activity, sow must to be performed between June and July at a 90 x 30 cm distance and to harvest the material at three months age(AU)

Prácticas agrícolas para el cultivo de Xanthium strumarium L (guizazo de caballo) con fines terapéuticos / Agricultural practices for the culture of Xanthium strumanium L (guizazo de caballo) with therapeutic aims

Xanthium strumarium (guizazo de caballo) se encuentra entre las plantas con antividad antimitótica. OBJETIVOS: determinar en esta especie los aspectos agrícolas que garanticen el adecuado material vegetal. MÉTODOS: se realizaron estudios durante 2007-2009, donde se evaluaron dos fechas de siembra: junio y julio; dos distancias de siembra 90 x 30 cm y 90 x 50 cm y dos momentos de cosecha: 3 meses de edad (parte aérea y raíces) en plantas que presentaban estado de floración-fructificación y 4 meses de edad (solo raíces) en plantas en fructificación. Las semillas, obtenidas de areales silvestres, se sembraron en parcelas, 3 repeticiones en cada caso. Se evaluó la altura de las plantas en el momento de la cosecha, se seleccionaron 10 plantas/parcelas y se cosecharon 39 plantas/parcelas en la distancia de 90 x 30 cm y 24 plantas en la distancia de 90 x 50 cm, en el caso del follaje se evaluaron los rendimientos de 10 plantas/parcelas en cada caso. RESULTADOS: se observó que bajo cultivo la altura de las plantas fueron mayores en las que se sembraron en junio, con distancia de 90 x 30 cm, en tanto que en las de julio se comportaron de forma similar, independientemente a las distancias de siembra empleadas y en correspondencia con ello los rendimientos resultaron iguales; sin embargo, cuando se quieren cosechar también las raíces, es preferible hacer la cosecha a los 3 meses de edad y, en este caso, los mayores valores se presentaron en las siembras de julio, con distancia de 90 x 30 cm. CONCLUSIÓN: para el aprovechamiento de la planta con doble propósito: parte aérea y raíces, pues en ambas se ha encontrado la actividad antimitótica, la siembra se debe realizar entre junio y julio a la distancia de 90 x 30 cm y recolectarse el material a la edad de 3 meses

Xanthium strumarium (guizazo de caballo) is among the plants with antimitotic activity. OBJECTIVES: to determine in this species the agricultural features to guarantee the appropriate plant material. METHODS: during 2007-2009 studies were conducted to assess to sow dates: June and July; two sow distances 90 x 30 cm and 90 x 50 cm at two sow periods: three months of age (aerial parts and roots) in plants with a flowering-fructification states and four months of age (only roots) in plants in fructification process. Seeds obtained from wild aerial plants were sowed in plots, three repetitions in each case. The plants height was assessed at the harvest moment, choosing 10 plants/lots and 39 plants/lots were growed at a 90 x 30 cm distance and 24 plants at the 90 x 50 cm distance, in the case of foliage the yields of 10 plants/lots were assessed in each case. RESULTS: there was that at culture the plants heights were higher in those sowed in June at a 90 x 30 cm distance while those sowed in July behaved in a similar way independently of the sow distances used and in correspondence with it, the yields were similar; however, when we desire to grow also the roots, it is preferable to grow at three months of age, and in this case, the higher values were in sows of July at a 90 x 30 cm distance. CONCLUSION: for the plant exploitation with a double aim: aerial parts and roots, since in both there is antimitotic activity, sow must to be performed between June and July at a 90 x 30 cm distance and to harvest the material at three months age