Microtubers were obtained from potato plants (Solanum tuberosum L.) cultured in vitro, they were used in following experiments. The impact of growth regulators (FLD, AgNO3, BA, ABA) was monitored in length of dormancy. The content of ABA in the budding tubers and the content of endogenous CK (BA, IP, DHZ, DHZR, Z) was determined during the dormancy as well. Production of ACC, ethylene, O2, CO2 and ethane was determined by gas chromatography. Variants containing FLD, AgNO3 and BA had a significant impact in the shortening of dormancy and stimulation the growth of buds microtubers. When they were used the occurrence of budding tubers was increased by 30-40 % over the control. Variant of ABA inhibited the growth of buds. ABA content correlated with the process of dormancy and the occurrence of budding tubers. The highest content of ABA was in variant with freshly collected dormant tubers. Concentration of various CK was dependent on the type of CK and monitored variant. Generally, It was slightly increased with occurrence of budding tubers.

The potato is recognized worldwide as an important source of food to decrease hunger, because of its nutritional traits, as well as an alternative to rural employment and financial income. In Brazil, potato is characterized by high dependence of cultivars of European origin, for this reason, many universities and companies have contributed to breeding researches, in an attempt to achieve cultivars with quality and adaptation it to our conditions. A strategy used by breeders is the early selection, to reduce costs and effort for clones maintenance and multiplication. The objective of this work was to test the canonical correlation, as a statistical tool to assist in the early selection of potatoes clones, to identify characters, related to tubers planted and their production. For this, there three experiments in three different seasons were conducted, in the experimental area Fitotecnia Department of the Federal University of Santa Maria, with 10 potatoes progenies. The characters used for the analysis of canonical correlation were the tubers planted and their production: length, larger diameter, smaller diameter and mass. The canonical correlation identified shows that there is a relationship between characters of the tubers planted and produced. The largest association occurs with tuber length, suggesting that if it were planted long tubers, you get, more elongated tubers as well. / A cultura da batata é mundialmente reconhecida como uma importante fonte de alimento no combate a fome, por suas qualidades nutricionais, bem como uma alternativa ao emprego rural e ingressos financeiros. No Brasil a batata caracteriza-se por uma grande dependência de cultivares de origem européia, motivo pelo qual, muitas universidades e empresas dedicam-se a pesquisa, na área de melhoramento, na tentativa de obter cultivares de qualidade e adaptada as nossas condições. Uma estratégia utilizada pelos melhoristas é a seleção precoce, por reduzir custos e trabalho para manutenção e multiplicação de clones. O objetivo deste trabalho foi testar a correlação canônica, como uma ferramenta estatística capaz de auxiliar na seleção precoce de clones de batata, identificando os caracteres, altamente relacionados, entre tubérculos plantados e sua produção. Para isto realizaram-se três ensaios, em três diferentes épocas, na área experimental do Departamento de Fitotecnia da Universidade Federal de Santa Maria, utilizando 10 progênies de batata. Os caracteres utilizados, para a realização da análise de correlação canônica, para os tubérculos plantados e sua respectiva produção foram: comprimento, maior diâmetro, menor diâmetro e massa. A correlação canônica identificou que há uma relação entre caracteres de tubérculos plantados e produzidos. A maior associação ocorre em comprimento de tubérculos, sugerindo que, ao plantar-se tubérculos mais longos obtém-se, também, tubérculos mais alongados.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-04-11T18:35:36Z No. of bitstreams: 1 texto completo.pdf: 2269796 bytes, checksum: 359867f02ec52728e20f089208e27d89 (MD5) / Made available in DSpace on 2018-04-11T18:35:36Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2269796 bytes, checksum: 359867f02ec52728e20f089208e27d89 (MD5) Previous issue date: 2018-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Um dos fatores que restringem a obtenção de maiores índices de produtividade na cultura da batata está relacionado com o crescimento excessivo dos caules e massa foliar, que é favorecido pelas altas temperaturas do verão, levando a redução da produtividade e menor teor de matéria seca dos tubérculos. Uma prática de manejo que pode ser utilizada para obter equilíbrio entre o crescimento da parte vegetativa e o órgão de reserva das plantas é a utilização de produtos reguladores ou retardantes do crescimento vegetal, os quais atuam inibindo a biossíntese de giberelina. O paclobutrazol e o trinexapac-ethyl são reguladores de crescimento utilizado na agricultura com finalidade de controlar o crescimento vegetativo, visando à redução do porte das plantas. Diante do exposto, o objetivo desse trabalho foi avaliar o crescimento e produção da batata cultivar Markies em função da aplicação dos reguladores de crescimento, paclobutrazol (PBZ) e trinexapac-ethyl (TE), em condições de verão. Foram conduzidos dois experimentos independentes. No primeiro experimento, PBZ a 0,125 e 0,250 L ha -1 e TE a 1,0 e 2,0 L ha -1 foram aplicados na forma de pulverização foliar, aos 35 dias após o plantio. No segundo, PBZ a 0,1; 1,0; 10 e 100 mg L -1 e TE a 1,0; 10; 100 e 1000 mg L -1 foram aplicados nas batatas-semente brotadas antes do plantio. Na aplicação via foliar, os reguladores de crescimento foram eficientes em antecipar o processo de tuberização. As plantas tratadas com PBZ e TE exibiram células epidérmicas maiores e uma única camada de células do mesofilo paliçádico mais alongadas. O tratamento com PBZ nas duas doses foi eficiente em aumentar o índice de clorofila das folhas e reduzir o tamanho das plantas, porém reduziu a massa fresca e seca total dos tubérculos, produção total por planta e a gravidade especifica dos tubérculos. No segundo experimento, o PBZ foi eficiente em reduzir o tamanho das plantas e aumentar o índice de clorofila, flavonoides e balanço de nitrogênio das folhas. As duas doses maiores (10 e 100 mg L -1 ) de PBZ atrasaram a emergência da parte aérea, o início da tuberização das plantas, reduziram o número de tubérculos por planta e o teor de amido dos tubérculos. As folhas exibiram células epidérmicas maiores, células do mesofilo paliçádico mais alongadas e mesófilo esponjoso mais espesso. Nos dois experimentos, o TE não foi eficiente em reduzir o comprimento das plantas, mostrando a sua seletividade somente a determinadas espécies. / One of the factors that restrict the obtaining of higher productivity indices in the potato crop is related to the excessive growth of stems and foliar mass, which is favored by high temperatures, leading to reduced productivity and lower dry matter content of tubers. A management practice that can be used to achieve a balance between the growth of vegetative part and the reserve organ of the plants is the use of plant growth retarding or regulating products, which act to inhibit the biosynthesis of gibberellin. Paclobutrazol and trinexapac-ethyl are growth regulators used in agriculture to control vegetative growth, aiming at reducing the size of plants and stimulating reproductive capacity. In view of the above, the objective of this work was to evaluate the growth, dry matter partition and production of potato cv. Markies as a function of growth regulators, paclobutrazol (PBZ) and trinexapac-ethyl (TE). Two independent experiments were conducted. In the first experiment, PBZ at 0.125 and 0.250 L ha -1 and TE at 1.0 and 2.0 L ha -1 were applied as foliar sprays at 35 days after planting. In the second, PBZ at 0.1; 1.0; 10 and 100 mg L -1 and TE at 1.0; 10; 100 and 1000 mg L -1 were applied to seed potatoes sprouted before planting. In the foliar application, treatments with growth regulators anticipated the tuberization process in potato plants, when compared to the control. PBZ treatment at both doses was efficient in increasing leaf chlorophyll content and reducing plant size, but it reduced the fresh and dry mass of the tubers, total yield per plant and the specific gravity of the tubers. Plants treated with PBZ and TE exhibited larger epidermal cells and a single layer of large and elongated palisade mesophyll cells. Treatments with PBZ were observed a thicker spongy mesophyll tissue. In the second experiment, the PBZ was efficient in reducing plant size and increasing the chlorophyll, flavonoid and nitrogen balance index of the leaves. The two higher doses (10 and 100 mg L -1 ) of PBZ delayed the emergence of aerial part, the beginning of plant tuberization, reduced the number of tubers per plant and the starch content of the tubers. Leaves from PBZ-treated seed potatoes at doses 10 and 100 mg L -1 exhibited larger epidermal cells, more elongated palisade mesophyll cells and thicker spongy mesophyll. In both experiments, the TE was not efficient in reducing the size of the plants, showing their selectivity only to certain species.

This diploma thesis deals with acidic proteins contained in the potato (Solanum tuberosum) tubers, or rather about their separation with chromatography techniques. For the analysis were chosen tubers of two czech potato varieties, Adéla and Westamyl. From the concentrated potato juice were eliminated basic and most of the patatin proteins with the gravity column chromatography. In the next step were applied the chromatography techniques on the anion and hydroxyapatite columns by the fast protein liquid chromatography (FPLC) system. On the anion column were separated protein fractions which contained proteins of molecular weight in the range of 15 kDa to 60 kDa (Adéla) and 15 kDa to 100 kDa (Westamyl). The most abundant were the proteins with molecular weight 15 kDa a 20 kDa. In the last step was used the mass spectrometry for the identification of chosen protein fractions.

The potato (Solanum tuberosum L.) crop serves as a staple food worldwide and is capable of reducing the world’s food shortages because unlike cereals and other agricultural crops, it is less affected by prices in the international markets. Research on alleviation of food crises suggested root and tuber crops such as potatoes to be the solution to the problem of food shortage. The crop is widely cultivated but is difficult to produce due to susceptibility to numerous pests and pathogenic organisms, as well as abiotic stresses. To control these pests and diseases, strategies to limit susceptibility to factors that interfere with the growth and development of plants, or breeding new varieties that are able to withstand stresses are being researched. Recent studies have shown that non essential nutrients such as Silicon (Si) are beneficial to plants in terms of yield, protection from fungal diseases and improved uptake of phosphorus. Since very little research has focused on the role of Si in improving potato production, three glasshouse pot trials were conducted at the Hatfield Experimental farm and Department of Plant Pathology glasshouses of the University of Pretoria to evaluate the effect of various soil amendments on potato yield and quality. The effect of these soil amendments on pH was also investigated as P-uptake and development of common scab in potatoes are pH dependent. The soil amendments consisted of different silicon sources and an agricultural lime. The Si sources were Calmasil slag (Middleburg) (30% Si- containing liming material), fly ash (50% Si nonliming material), and Si fume/ash (99% Si non-liming material). Agricultural lime (CaCO3) was included as a control. The purpose of the first two trials was to identify the most promising silicon-containing source for potato production, while the third trial evaluated the effect of this silicon source on soil pH and potato tuber yield. In all three trials, agricultural lime was used as a control. Due to the high demand for nutrients by the potato crop, other nutrient elements were added to the soil through fertigation every 7 to 14 days, depending on the growth stage of the plants. Plants were irrigated with distilled water when necessary to maintain an adequate moisture level i.e. moist but not too wet. Weekly observations on growth parameters were made. To select the most promising soil amendment, parameters such as leaf chlorophyll content, plant height, tuber number and mass (Fwt), fresh and dry weight (top growth) and change in soil pH were analyzed. Slag treated plants tended to produce tubers with higher mass and better appearance. In this study the highest increase in soil pH was observed in soil mixed with slag, compared to all the other silicon sources. Although there was no significant difference observed among treatments there was a distinct difference in plant growth between trials when soil was amended with lime and slag. Plants treated with slag tended to produce tubers that weigh more, whilst plants treated with lime grew taller and had the highest tuber number. There was a significant rise in soil pH from both lime and slag, which might have in turn influenced vegetative and tuber growth. / Dissertation (MInst(Agrar)--University of Pretoria, 2013. / gm2014 / Plant Production and Soil Science / unrestricted

The aim of our diploma thesis was to evaluate the influence of drop irrigation on achieved profit and the quality of chosen consumable variety of potatoes. The field experiment was established on lands of experimental field station AF MENDELU in Žabčice, Brno during a trial period from 2016 to 2017. Two consumable varieties of potatoes with different duration of vegetative period – very early season variety called Monika and mid-early season variety called Jolana – were used for experiments. The influence of additional drop irrigation on profit and strachiness of potatoe tubers was closely monitored. The experiment consisted of four options, always in four repetitions. Particular options were: Control, P60, P65 and P70% of usable water capacity. On the basis of attained results it is possible to note that the drop irrigation is very effective and efficient way to raise profit and quality of potatoes. Due to practical and economic reasons, P60 and P65 appear to be an optimal option of drop irrigation providing medium soil humidity.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of this study was to evaluate the processing quality of potato tubers to identify superior clones under different growing conditions of Southern Brazil. Two trials were carried out in different conditions. The first trial was carried out during summer in São Joaquim, SC, and during spring and fall seasons in Júlio de Castilhos, RS to evaluate the genotype x environmental interaction for tuber quality and the gain from selection. A total of 18 potato genotypes were evaluated for chip color, dry mass, reducing sugar and amylose contents. Summer growing conditions increase the gain from selection and the selection is correlated with both spring and autumn seasons. The second trial was carried out to evaluate the yield and the tuber quality of potato clones in early harvest during autumn and spring seasons in Júlio de Castilhos, RS. A total of 12 potato genotypes were evaluated for yield, dry mass, sucrose and reducing sugar contents in tubers harvested at 70 and 90 days after planting (DAP), autumn season, and 70 DAP, spring season. Potato tubers harvested at 90 DAP in autumn and at 70 DAP in spring do not get the minimal processing quality necessary for the industry. / O objetivo desse trabalho foi avaliar a qualidade de processamento de tubérculos de batata para a seleção de clones em diferentes condições de cultivo no Sul do Brasil. Para isso foram considerados dois estudos. No primeiro estudo, foram conduzidos experimentos em condições de cultivo de verão em São Joaquim (SC), e de primavera e outono, em Júlio de Castilhos (RS), representativos das principais épocas de cultivo da batata na região Sul do Brasil, com o objetivo de avaliar a interação genótipo x ambiente em caracteres de qualidade de tubérculos de batata e seus reflexos no ganho de seleção. Em cada cultivo, foram avaliados 18 clones de batata para os caracteres coloração de chips e da composição dos tubérculos em teores de matéria seca, açúcares redutores, amido e amilose. O cultivo de verão maximiza os ganhos genéticos, sendo a seleção neste ambiente correlacionada aos ambientes de primavera e outono. No segundo estudo, realizado em Júlio de Castilhos (RS), foram conduzidos experimentos com o objetivo de avaliar a produtividade e a qualidade de tubérculos de clones de batata com maturidade precoce no outono e na primavera. Foram avaliados 12 clones de batata para produtividade, matéria seca, sacarose e açúcares redutores de tubérculos colhidos aos 70 e 90 dias após o plantio (DAP) no outono e aos 70 DAP na primavera. Os tubérculos colhidos aos 90 dias após o plantio de outono e aos 70 dias após o plantio de primavera ainda não atingiram a qualidade mínima para o processamento industrial.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Potato tubers are used as food and seed. Post-harvest conditions affect tubers for both usages, since physiological changes occur during tuber storage. The objective of this work was to assess the processing quality and time until tuber sprouting of advanced clones of potato. We evaluate thirteen clones and two check varieties of potato in a storage room at 10ºC in two years. The processing quality was evaluated right before loading and after 30, 60, 90 and 120 days of storage for the fresh and dry weight content, chip color and reduced sugars. The experiment was a factorial of clone and storage time in the complete random design, with four repetitions. The percentage of fresh weight loss increased over time during storage, mainly at 120 days. The assessed clones presented dry weight content between 17.4% to 25.2 % during the cold storage. Chip color showed an intense yellow tone and acceptable color classification for the processing industry, even with the increase of reduced sugars during storage. The storage at 10 ºC extended in a 100 days the sprout process. The refrigerated storage promote physiological changes on the tubers, but this changes don´t compromise the use in the industry processing and also allows to increase the storability period of the tubers for both consumption and seeds. / Os tubérculos de batata são destinados tanto para a alimentação quanto para a propagação. Ambas as finalidades são influenciadas pelas condições de armazenamento, que é capaz de promover mudanças fisiológicas nos tubérculos. O objetivo deste trabalho foi avaliar a qualidade de processamento e o tempo de armazenamento até a brotação dos tubérculos de clones avançados de batata. Foram avaliados 13 clones de batata e duas testemunhas, que foram submetidos ao armazenamento em câmera refrigerada a uma temperatura de 10 ºC em dois anos. A qualidade de processamento foi avaliada no momento do armazenamento, imediatamente após a cura, e aos 30, 60, 90 e 120 dias. Os caracteres avaliados foram massa fresca e seca, coloração de chips e o teor de açúcares redutores. Também foi anotado o número de dias para o rompimento da dormência e da dominância apical, quando respectivamente os tubérculos apresentaram um e dois brotos com pelo menos 2 mm de comprimento. O experimento foi um fatorial de clones e épocas de avaliação segundo o delineamento experimental inteiramente casualizado, com quatro repetições. O percentual de perda de massa fresca foi crescente ao longo do armazenamento refrigerado, sobretudo aos 120 dias. Os clones avaliados apresentaram teor de massa seca entre 17,4 % a 25,2 % ao longo do armazenamento refrigerado. A coloração de chips apresentou uma tonalidade amarela intensa e uma classificação aceitável para a indústria, mesmo com o aumento no teor de açúcares redutores após o armazenamento. O armazenamento a 10 ºC prolongou o processo de brotação em até 100 dias de armazenamento. O armazenamento refrigerado promove mudanças fisiológicas nos tubérculos, mas estas mudanças não comprometem a utilização na indústria de processamento, e também possibilita armazenar os tubérculos por um longo período para o consumo e plantio.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Micro-propagation is a common technique to produce disease free potato materials. Mini-cuttings of just acclimatized plantlets or older plants associated with micro-propagation may reduce production costs of potato mini-tubers. This work was carried out to study the micro-propagation and mini-cutting techniques to maximize the production of mini-tubers and to minimize the costs of potato seeds. Two experiments were conducted, being in the first evaluated the micro-propagation and acclimatization of plantlets and in the second evaluated the mini-cutting of potato plants. The first experiment was conducted in two steps. In vitro growth of potato explants were evaluated in two concentrations of MS medium (½ MS and MS), three sucrose doses (30, 45 and 60 g L-1), and three clones (Asterix, Macaca e SMINIA793101-3). The same treatment combinations were evaluated during plantlet acclimatization in two systems (floating and sand). The mini-cutting was evaluated in three experiments. The effect of irrigation solution (tap water, nutrient solution and the combination) and the physiological age of stock plant (just acclimatized and in mini-tuber production) were evaluated in the mini-cutting rooting of Asterix, Macaca and SMINIA793101-3 clones. A third experiment was carried out to evaluate the effect of indol butyric acid (IBA) (0; 300; 600; 900 ppm) in mini-cutting rooting of Asterix clone. The MS medium with 50% of the salt concentration increases the plantlet survival during acclimatization. The sucrose has no effect on plantlet acclimatization. Both floating and substrate (sand) are suitable systems for acclimatization of potato plantlets. Mini-cuttings root in sand as substrate irrigated with tap water or nutrient solution. Apical mini-cuttings are suitable for the production of potato plantlets. Rooting potential of mini-cuttings is affected by the advance of the physiological age of the stock plant. / A micropropagação é uma técnica comumente utilizada para a produção de material propagativo de batata livre de doenças. Associada a essa técnica, a miniestaquia de plântulas recém aclimatizadas ou em produção pode ser uma forma de reduzir os custos de produção de minitubérculos de batata. Este trabalho foi conduzido com o objetivo de estudar a micropropagação e a miniestaquia, para maximizar a produção de mudas e minimizar os custos da batata-semente. Dois experimentos foram conduzidos, sendo no primeiro avaliado a micropropagação e aclimatização de plântulas e, no segundo, avaliado a miniestaquia de plantas batata. O primeiro experimento foi conduzido em duas etapas. Em laboratório foi avaliado o crescimento dos explantes em função da combinação de concentrações do meio MS (½ MS e MS completo), com doses de sacarose (30, 45 e 60 g L-1) em três clones (Asterix, Macaca e SMINIA793101-3). Em telado foi avaliado o efeito dos tratamentos aplicados na micropropagação sobre a aclimatização de plântulas em dois sistemas (flutuação e areia). A miniestaquia foi estudada em três experimentos. Um experimento foi conduzido para avaliar o efeito da solução de irrigação (água, solução nutritiva e a combinação de ambas) e outro a idade da planta matriz (recém aclimatizada e em produção) sobre o enraizamento de miniestacas dos clones Asterix, Macaca e SMINIA793101-3. Um terceiro experimento foi conduzido para avaliar o efeito do ácido indol-butírico (AIB) (0, 300, 600 e 900 mg L-1) no enraizamento das miniestacas do clone Asterix. O meio ½ MS, independente da dose de sacarose, aumenta a sobrevivência das plântulas de batata durante a aclimatização. Tanto o sistema com flutuação, quanto com substrato (areia) podem ser utilizados para a aclimatização de plântulas de batata. Miniestacas apicais podem ser utilizadas para a produção de mudas de batata, no sistema de enraizamento com substrato (areia), irrigadas com água de torneira ou solução nutritiva. O potencial de enraizamento das miniestacas é negativamente afetado pelo avanço da idade fisiológica da planta matriz.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The potato (Solanum tuberosum L.) is the fourth culture in economic importance in the world after the wheat, of the maize and the rice. Consequently, the research with this species can bring benefits for a considerable number of people. Tissue culture has contributed in the genetic improvement of the potato in the direction of attainment of free plants of virus and micropropagation of elite genotypes. However, plants regenerated from tissue culture can show variation in agronomic characteristics important. The induced variation by tissue culture is called somaclonal variation. The occurrence of somaclonal variation can be identified in vitro for parameters still auxiliary as the multiplication rate. In field, the use of morphologic markers can be used to identify somaclones. The work had as objective: To evaluate the behavior in vitro of cultivating them of potato Asterix and Macaca through the multiplication rate observed during a period of eight months. Identify variant somaclonais proceeding of the culture in vitro of them cultivate Asterix and Macaca through morphological markers.To evaluate the genotype effect, culture-age effect and the type of explant on the occurrence of somaclones. Multiplication rate was used in the attempt to identify the occurrence of somaclonal variation in cultivating of potato Asterix and Macaca with three sources of explantes (apex stems, stems and callus) and two ages of subculture (70 months-old clone and 12 months-new clone).The morphological characterization of the plants and basic tubercles was effected according to described methodology for COLLARES (2002) based in the minimum describers of the potato (Solanum tuberosum L.). The multiplication rat of cultivating Macaca was greater that of Asterix and the behavior of the multiplication rate of Macaca oscillated between extreme values different of the observed one in Asterix. The rate multiplication depends on cultivar.Through the morphological characterization it was possible to identify that to cultivate them Asterix and Macaca had presented different behavior how much to the stability of the morphologic characteristics when passing for culture in vitro. The explante derived from callus in such a way presented the biggest occurrence of somaclonais variants for the treatments that had included Asterix as Macaca. The age of subculture of 70 months and 12 months had not been adjusted for maintenance of disgnostic characteristics of them to cultivate Asterix and Macaca due to occurrence of somaclones. It was possible to identify variant somaclonais in the treatments that had included Asterix and Macaca through the minimum describers of the potato. / A batata (Solanum tuberosum L.) é a quarta cultura em importância econômica no mundo depois do trigo, do milho e do arroz. Conseqüentemente, a pesquisa com esta espécie pode trazer benefícios para um considerável número de pessoas. A cultura de tecidos tem contribuído no melhoramento genético da batata no sentido de obtenção de plantas livres de vírus e micropropagação de genótipos elite. No entanto, plantas regeneradas a partir de cultura de tecidos podem exibir variação em importantes caracteres agronômicos. A variação induzida por cultura de tecidos é chamada de variação somaclonal. A ocorrência de variação somaclonal pode ser identificada ainda in vitro por parâmetros auxiliares como a taxa de multiplicação. Em campo, o emprego de marcadores morfológicos pode ser usado para identificar somaclones. O trabalho teve como objetivos: avaliar o comportamento in vitro das cultivares Asterix e Macaca de batata através da taxa de multiplicação observada durante um período de oito meses. Identificar variantes somaclonais provenientes do cultivo in vitro das cultivares Asterix e Macaca através de marcadores morfológicos; avaliar o efeito do genótipo, do tempo de subcultivo e do tipo de explante sobre a ocorrência de variantes somaclonais. Foi empregada a taxa de multiplicação na tentativa de identificar a ocorrência de variação somaclonal na cultivares de batata Asterix e Macaca com três fontes de explantes (ápice caulinar, segmento nodal e calo) e dois tempos de subcultivo (70 meses-clone velho e 12 meses-clone novo). A caracterização morfológica das plantas e tubérculos básicos foi efetuada segundo metodologia descrita por COLLARES (2002) baseada nos descritores mínimos da batata. A taxa de multiplicação da cultivar Macaca foi maior que a de Asterix e o comportamento da de Macaca oscilou entre valores extremos diferente do observado em Asterix. A taxa de multiplicação in vitro depende da cultivar. Através da caracterização morfológica foi possível identificar que as cultivares Asterix e Macaca apresentaram comportamento diferente quanto à estabilidade dos caracteres morfológicos ao passarem por cultivo in vitro. O explante derivado de calo apresentou a maior ocorrência de variantes somaclonais, tanto para os tratamentos que incluíram Asterix como Macaca. Os tempos de subcultivo de 70 meses e 12 meses não foram adequados para manutenção dos caracteres diagnósticos das cultivares Asterix e Macaca devido à ocorrência de variantes somaclonais. Foi possível identificar variantes somaclonais nos tratamentos que incluíram Asterix e Macaca através dos descritores mínimos da batata.