Master of Science / Department of Agronomy / Dorivar Ruiz Diaz / The limitation of an essential nutrient for plant growth can affect crop yield. Research has been focused mainly on macronutrients, nevertheless micronutrients are equally important. This thesis is divided into three studies, which had the purpose of assessing frequent questions that producers have about micronutrient fertilizers and their effect on several crops in Kansas. The objective of the first study was to summarize and analyze results from studies since 1962 until 2015 to verify responses to zinc (Zn) and sulfur (S) fertilization in corn (Zea mays), sorghum (Sorghum bicolor (L.) Moench), wheat (Triticum aestivum) and soybean (Glycine max (L.) Merr). The treatments evaluated consisted of fertilizer Zn or S application versus their respective unfertilized treatments. Zinc fertilization significantly increased corn yield; no significant response was found for sorghum, wheat and soybean. Sulfur fertilization did not increase yields on corn and wheat. The objectives of the second study were: (i) to evaluate soybean response to S and micronutrients boron (B), copper (Cu), manganese (Mn), and Zn fertilizer application and to assess soil test and soybean seed and tissue nutrient concentration with fertilization. Treatments consisted of an unfertilized control, micronutrient fertilizer as individual nutrient for B, Cu, Mn, S and Zn applied broadcast pre-plant, in addition to a blend of these nutrients using two different placements (broadcast and band). Secondary and micronutrient fertilization showed no significant effect on soybean yield at any of the ten locations. Zinc fertilization showed significant effects on soybean tissue and seed Zn concentration. The objective of the third study was to evaluate soybean tissue nutrient response to micronutrient fertilizers in field strips with high variability in soil properties in the area evaluated. The study consisted of two strips (with and without fertilizer) and replicated three times. The treatment with fertilizer included a blend of Cu, Mn and Zn at a rate of 11.2 kg ha⁻¹ and B at a rate of 2.8 kg ha⁻¹. Initial soil tests B, Cu, Mn and Zn were not good indicators of soybean tissue response. Within-field variability of soybean Zn and B tissue content were affected by soil pH and organic matter; and these factors may be used to help explain field variability in plant availability. The micronutrient blend treatment showed higher tissue Zn and B values compared to the control. When pH ranged from 5.5 to 7.6, B in soybean tissue was higher on the control than the micronutrient blend treatment. Copper concentration in soybean tissue did not show significant difference between treatments at any location, regardless of pH and organic matter levels.

Frente ao aumento populacional e consequente incremento na demanda por alimentos, é importante estabelecer um melhor aproveitamento da área de cultivo, objetivando a colheita de produtos agrícolas em maior quantidade e de melhor qualidade. O aumento da concentração de micronutrientes nos produtos colhidos, especialmente de zinco é um desafio crescente para a agricultura, com possibilidade de trazer benefícios à saúde humana e à produtividade da cultura. Nesse sentido, a aplicação foliar de zinco realizada periodicamente, à partir da antese floral, é uma técnica capaz de incrementar o teor do micronutriente nas sementes e biofortificar os grãos de feijão e trigo, causando melhoria de aspectos agronômicos (crescimento vegetativo e produtividade da cultura) de plantas provenientes dessas sementes, além de resultar proveitos para a saúde humana daqueles que se alimentam de produtos biofortificados, e ainda com potencial para produzir grãos e sementes como produtos de maior valor comercial no mercado, valendo-se de inovação tecnológica. Porém, atualmente pouco se conhece sobre os diversos aspectos desta técnica. Assim sendo, objetivou-se: (i) elucidar o efeito da aplicação foliar de zinco, à partir da antese floral, como método para incrementar o teor do micronutriente nos grãos de feijão (Phaseolus vulgaris L.) e de trigo (Triticum aestivum L.), em substrato com teor adequado do micronutriente (ii) utilização de diferentes fontes de zinco aplicadas via foliar visando estabelecer a melhor fonte para o aumento do teor do micronutriente no grão de feijoeiro e (iii) determinação das doses de zinco mais adequadas a serem aplicadas através de pulverização foliar visando o aumento do teor do nutriente no grão de plantas de feijão e de trigo. Com base nos resultados obtidos, concluiu-se que (i) a aplicação foliar de zinco realizada periodicamente, à partir da antese floral é capaz de aumentar o teor do micronutriente em grãos de feijão e de trigo; (ii) a fonte mais viável para o enriquecimento de grãos de feijão é o sulfato de zinco; (iii) e todas as doses testadas (125, 250, 375 e 500 g Zn ha-1) aplicadas via foliar na forma de sulfato de zinco foram efetivas para o enriquecimento de grãos de feijão e de trigo, em relação ao controle (0 g Zn ha-1). / In view of the population increase and consequent growth of food demand, it is important to establish a better utilization of the cultivation area, aiming the harvest of agricultural products in greater quantity and of better quality. The increased concentration of micronutrients in products harvested, especially zinc, is a growing challenge for agriculture, with potential to bring benefits to human health and crop productivity. In this matter, the foliar zinc application performed periodically starting at floral anthesis is a technique capable of increasing the micronutrient content in the seeds and biofortifying grains of common bean and wheat, causing agronomic aspects improvement (vegetative growth and crop productivity) of plants derived from these seeds, in addition to bringing benefits to human health of those who feed on biofortified products, and still with potential to produce grains and seeds as products of greater commercial value in the market, being a technological innovation. However, currently little is known about the aspects that circumvent this technique. The objective of this study was: (i) elucidate the effect of foliar application of zinc, starting at floral anthesis, as a method to increase the micronutrient content of common bean (Phaseolus vulgaris L.) and wheat (Triticum aestivum L.) (ii) the use of different sources of zinc applied in a foliar way, in order to establish the best source for increasing the micronutrient content in common bean grains, and (iii) the determination of the most suitable zinc doses, applied by foliar spraying to increase the nutrient content of common bean and wheat plants. Based on the results obtained, it was concluded that (i) the periodic application of zinc foliar application starting at floral anthesis is capable of increasing the micronutrient content in common bean and wheat grains; (ii) the most viable source for the enrichment of bean grains is zinc sulphate; (iii) and all the doses tested (125, 250, 375 and 500 g Zn ha-1) applied via foliar in the form of zinc sulfate were effective for the enrichment of common bean and wheat grains, in relation to the control (0g Zn ha-1).

Orientador: André Rodrigues dos Reis / Resumo: O selênio (Se) é um nutriente para humanos e animais e um elemento benéfico para as plantas, sua baixa concentração nos solos do Brasil pode gerar deficiência nos animais e humanos. O fitato é a principal forma de reserva de fósforo (P) encontrado nas sementes de plantas, sendo considerado um “anti-nutriente” por formar complexos não digeríveis com nutrientes como Fe, Ca e Zn. Desta forma, existe a necessidade de se buscar alternativas para aumentar os teores de Se e reduzir o teor de fitato nas partes comestíveis de cultivares modernos. O objetivo do trabalho foi avaliar doses e fonte ótimas de Se a serem aplicadas em condições brasileiras, bem como a influência do Se na produção e qualidade nutricional em 29 genótipos de feijão-caupi. Para isso, foram desenvolvidos dois experimentos a seguir: Experimento 1: Foi avaliada a eficiência da biofortificação agronômica utilizando 2 fontes de Se (selenato e selenito) e 7 doses de Se (0; 2,5; 5,0; 10,0; 20,0; 40,0 e 60 g ha-1) aplicados via solo, foi realizada analise de fitatos nos grãos. Experimento 2: Foi realizado um experimento para caracterizar a absorção e acúmulo de Se, teor de fitatos, açucares, proteínas de reversa e amino ácidos nos grãos de diferentes genótipos de feijão-caupi, nesse experimento, 29 genótipos foram avaliados na presença e ausência de Se (0 e 25 kg ha-1), cultivados até o final do ciclo para a obtenção dos grãos. No experimento 1, observou-se que a aplicação de selenato proporciona maiores concentrações d... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Fructans are polysaccharides that are made up mainly of fructose. They are non-digestible carbohydrates and act as prebiotics to selectively promote the growth of colonic bifidobacteria, thereby improving human gut health. Fructans are present in the grain of wheat (Triticum aestivum L.), a staple food crop. Until now, there has been no research on genetic improvement of the concentration of fructans in wheat grain, partly because it has been difficult to accurately measure. One aim of this research project was to develop a simple and effective method to measure the fructan concentration in wheat grain. This was achieved by modifying a method that involves extraction of fructans from wheat grain followed by enzymatic hydrolysis to break down fructans into monosaccharides and quantification by anion-exchange liquid chromatography coupled with pulsed amperometric detection. The modified procedure is reliable and allows the handling of large numbers of flour samples at a relatively low cost, and can therefore be useful for assessing large numbers of wheat breeding lines. Using this method, grain samples taken from a diverse set of 117 wheat cultivars and breeding lines, including parents of mapping populations, were analysed for grain fructan concentration. There was significant genotypic variation among these materials, with grain fructan concentration ranging from 0.3 to 2.3% of grain dry weight. There was no evidence of strong genotype-byenvironment interaction; the fructan concentrations of the same genotypes were positively correlated over different environments in Australia. Genetic mapping was carried out to detect and map loci affecting grain fructan concentration in wheat using a doubled haploid population derived from a cross between Berkut (high fructan) and Krichauff (low fructan). Grain samples were obtained from two field sites in South Australia and one in Kazakhstan. Fructan concentration varied widely within the population (0.6-2.6% of grain dry weight), with heritability estimated as h² = 0.71. A linkage map of 528 molecular markers covering 21 wheat chromosomes was used for locating quantitative trait loci (QTL). Genetic mapping identified two major QTLs on chromosomes 6D and 7A, with the (high fructan concentration) alleles contributed from Berkut, contributing to a 30-40% increase in wheat grain fructan compared to the Krichauff alleles. Effects of these chromosome regions were validated in additional environments and in another mapping population, Sokoll/Krichauff, with the favourable alleles contributed from Sokoll. The major QTL on chromosome 7A was in the same region with a reported fructosyltransferase orthologue (AB029888), while the major QTL on chromosome 6D seemed to be co-located with a reported gene encoding for a fructan-degrading enzyme 1-exohydrolase (1-FEHw2). It is concluded that grain fructan concentration of wheat can be improved by breeding and that molecular markers could be used to select effectively for favourable alleles in two regions of the wheat genome. / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2009

Fructans are polysaccharides that are made up mainly of fructose. They are non-digestible carbohydrates and act as prebiotics to selectively promote the growth of colonic bifidobacteria, thereby improving human gut health. Fructans are present in the grain of wheat (Triticum aestivum L.), a staple food crop. Until now, there has been no research on genetic improvement of the concentration of fructans in wheat grain, partly because it has been difficult to accurately measure. One aim of this research project was to develop a simple and effective method to measure the fructan concentration in wheat grain. This was achieved by modifying a method that involves extraction of fructans from wheat grain followed by enzymatic hydrolysis to break down fructans into monosaccharides and quantification by anion-exchange liquid chromatography coupled with pulsed amperometric detection. The modified procedure is reliable and allows the handling of large numbers of flour samples at a relatively low cost, and can therefore be useful for assessing large numbers of wheat breeding lines. Using this method, grain samples taken from a diverse set of 117 wheat cultivars and breeding lines, including parents of mapping populations, were analysed for grain fructan concentration. There was significant genotypic variation among these materials, with grain fructan concentration ranging from 0.3 to 2.3% of grain dry weight. There was no evidence of strong genotype-byenvironment interaction; the fructan concentrations of the same genotypes were positively correlated over different environments in Australia. Genetic mapping was carried out to detect and map loci affecting grain fructan concentration in wheat using a doubled haploid population derived from a cross between Berkut (high fructan) and Krichauff (low fructan). Grain samples were obtained from two field sites in South Australia and one in Kazakhstan. Fructan concentration varied widely within the population (0.6-2.6% of grain dry weight), with heritability estimated as h² = 0.71. A linkage map of 528 molecular markers covering 21 wheat chromosomes was used for locating quantitative trait loci (QTL). Genetic mapping identified two major QTLs on chromosomes 6D and 7A, with the (high fructan concentration) alleles contributed from Berkut, contributing to a 30-40% increase in wheat grain fructan compared to the Krichauff alleles. Effects of these chromosome regions were validated in additional environments and in another mapping population, Sokoll/Krichauff, with the favourable alleles contributed from Sokoll. The major QTL on chromosome 7A was in the same region with a reported fructosyltransferase orthologue (AB029888), while the major QTL on chromosome 6D seemed to be co-located with a reported gene encoding for a fructan-degrading enzyme 1-exohydrolase (1-FEHw2). It is concluded that grain fructan concentration of wheat can be improved by breeding and that molecular markers could be used to select effectively for favourable alleles in two regions of the wheat genome. / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2009

Made available in DSpace on 2015-03-26T13:36:40Z (GMT). No. of bitstreams: 1 texto completo.pdf: 890349 bytes, checksum: 3a3c4b6898edfb8ec6ee997137629c1e (MD5) Previous issue date: 2009-03-20 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Plants acquired strategies I and II for iron absorption. Strategy I occurs in terrestrial plants and includes the reduction of iron in the ferric form (Fe+3) to ferrous form (Fe+2). Strategy II of iron absorption is present in grasses and is characterized by the release of phytosiderophores to the environment that chelate ferric iron. The grain filling process in cereals involves the transfer of assimilates directly from the xylem to the grain and also remobilization of assimilates from vegetative organs through the phloem. The aim of this work was to study the pattern of accumulated nutrients in seeds of rice genotypes cultivated in two regions of Brazil and to study the pattern and correlations among the nutrients accumulated in the grain. Moreover, it was verified the occurrence of transcripts homologous to rice (Oryza sativa) gene families known to be related to iron homeostasis in ESTs databases of Sorghum bicolor, Zea mays, Triticum aestivum and Saccharum officinalis and in a database containing only maize (Z. mays) endosperm ESTs. These analyses pointed to gene families that are functionally expressed in these species and specifically during the formation of the maize grain. For the analysis of accumulation of nutrients in the grain it was used ICP-MS and the data were subjected to statistical analysis: ANOVA, Pearson correlation and path analysis. The Pearson correlation results of accumulated nutrients in the grain do not demonstrated the direct and indirect effects of nutrients accumulated. On the other hand, the path analysis of these same data revealed a direct correlation of Fe with P, S and Ca in the experiment conducted in MG and direct correlation of Fe with P in the experiment conducted in the RS. The data of correlation between iron content in flag leaves and panicle of rice in different stages of development showed positive correlation. Moreover, the levels of Fe accumulated in the grain of the genotypes grown in MG were higher compared to those grown in RS. To verify the occurrence of homology, the amino acid sequences related to the rice transcripts were obtained from NCBI and KOME databases. The sequences of ESTs from other grass species were obtained from TIGR-Plant transcripts assemblies program and the maize endosperm database was obtained from NCBI. The genes were aligned using the program BLAST2 with TBLASTN tool with e-value of 1e-10 and minimal identity of 40%. It was found counterparts of the gene families studied in all species evaluated. The NAS gene family, related to phytosiderophores synthesis showed high conservation (about 70%) among Poaceae family members studied, except wheat and maize endosperm. The OsFER1 gene showed high conservation (80%) among all members of Poaceae. This suggests the importance of these gene families in the transport and accumulation of iron among the Poaceae species. It was found representatives from each one of the families IRT1, YSL and ZIP in maize endosperm which suggests that these genes may be functionally expressed during the formation of maize grain. / As plantas adquiriram estratégias I e II de absorção do ferro. A estratégia I ocorre em plantas terrestres e inclui a redução do ferro da forma férrica (Fe+3) para a forma ferrosa (Fe+2). A estratégia II de absorção de ferro está presente nas gramíneas e é caracterizada pela liberação de fitosiderósforos no ambiente que se complexam ao íon férrico. O processo de enchimento do grão em cereais envolve a transferência de assimilados diretamente do xilema para o grão e também a remobilização de assimilados de órgãos vegetativos, através do floema. O objetivo do presente trabalho foi estudar o padrão de nutrientes acumulados nas sementes de genótipos de arroz cultivados em duas regiões do Brasil e estudar o padrão e as correlações entre os nutrientes acumulados no grão. Além disso, foi verificada a ocorrência de transcritos homólogos a famílias gênicas de arroz (Oryza sativa) conhecidamente relacionadas com homeostase de ferro em bancos de ESTs de Sorghum bicolor, Zea mays, Triticum aestivum e Saccharum officinalis e em um banco contendo apenas ESTs de endosperma de milho (Z. mays). Estas análises permitiram prever quais famílias gênicas são funcionalmente expressas nestas espécies e especificamente durante a formação do grão de milho. Para as analises de acúmulo de nutrientes no grão foi utilizado o ICP-MS e os dados foram submetidos às analises estatísticas: ANOVA, correlação de Pearson e análise de trilha. Os resultados de correlação de Pearson dos nutrientes acumulados no grão não evidenciaram os efeitos diretos e indiretos dos nutrientes acumulados. Por outro lado a análise de trilha destes mesmos resultados demonstrou efeitos de correlação direta do Fe com P, S e Ca no experimento realizado em MG e correlação direta do Fe com P no experimento realizado no RS. Os dados de correlação entre teor de ferro acumulado nas folhas bandeiras de arroz e nas panículas nos diferentes estádios de desenvolvimento tiveram correlação positiva. Além disso, os teores de Fe acumulado no grão dos genótipos cultivados em MG foram superiores comparados aos cultivados no RS. Para verificar a ocorrência de homologia, as seqüências de aminoácidos referentes aos transcritos em arroz foram obtidas a partir do banco de dados NCBI e KOME. As seqüências de ESTs de banco de dados das espécies de gramíneas foram obtidas a partir do programa TIGRPlant transcripts assemblies e do banco de endosperma de milho foi obtido do NCBI. Os genes foram alinhados utilizando o programa BLAST2 com a ferramenta TBLASTN com e-value de 1e-10 e identidade mínima de 40%. Foram encontrados homólogos das famílias gênicas estudadas em todas as espécies avaliadas. A família gênica NAS, relacionada com a síntese de fitosideróforos, possui alta conservação (cerca 70%) entre os genes da família Poaceae estudada, com exceção do trigo e endosperma de milho. O gene OsFER1 apresentou alta conservação (cerca de 80%) entre todos os genes de Poaceae. Isto indica a importância dessas famílias gênicas no transporte e acúmulo de ferro entre as espécies de Poaceae. Foram encontradas representantes de cada uma das famílias IRT1, YSL e ZIP no endosperma de milho o que sugere que esses genes possam ser funcionalmente expressos durante a formação de grãos em milho.

Submitted by Morgana Andrade (morgana.andrade@ufes.br) on 2016-03-18T17:22:54Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação _lidiane.pdf: 714346 bytes, checksum: 6a87adcea4d9735de717a47c7ab65a18 (MD5) / Approved for entry into archive by Morgana Andrade (morgana.andrade@ufes.br) on 2016-03-21T17:18:23Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação _lidiane.pdf: 714346 bytes, checksum: 6a87adcea4d9735de717a47c7ab65a18 (MD5) / Made available in DSpace on 2016-03-21T17:18:23Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação _lidiane.pdf: 714346 bytes, checksum: 6a87adcea4d9735de717a47c7ab65a18 (MD5) / FAPES / O feijoeiro (Phaseolus vulgaris L.) é um dos principais alimentos consumidos no Brasil, rico em vitaminas, carboidratos e minerais. É crescente o número de pesquisas que integram desde o melhoramento de plantas e o manejo da adubação para incrementar nutrientes nas partes comestíveis, desenvolvendo plantas com maiores teores de vitaminas e micronutrientes. A introdução de alimentos biofortificados como o feijão, complementa a nutrição humana que sofre com desnutrição. Sendo assim, é importante conhecer como as condições de cultivo influenciam na qualidade do grão e na importância para obtenção de um alimento com maior valor nutricional. Além de conhecer até que ponto a influência de planta daninha afeta a produção e a absorção de nutrientes pelo feijoeiro. O objetivo deste trabalho foi analisar as características agronômicas e nutricionais influenciadas pela interferência de planta daninha, efeito da adubação e do solo, nas cultivares de feijão. Foi avaliado o teor de clorofila, número de folhas, diâmetro do caule, número de vagem por planta, índice de colheita por planta, massa seca da trapoeraba, relação grão e lócus, peso médio de sementes e análise de ferro e zinco nas folhas e nos grãos. Os resultados obtidos no estudo apontaram que a competição com trapoeraba afetou algumas características agronômicas, devido à competição por nutriente. O solo para cultivo também interferiu na produção, o solo eutrófico proporcionou melhores resultados das cultivares. A adubação não interferiu nos teores de ferro e zinco nos grãos do feijoeiro. As cultivares BRS Agreste, BRS Ametista e BRS Estilo apresentaram melhores resultados na maioria das características analisadas. Por fim, conclui-se que a produção do feijoeiro, necessita de um solo com uma boa nutrição, um bom teor de matéria orgânica, manejo da adubação e de plantas daninhas para aumentar a produção.

Frente ao aumento populacional e consequente incremento na demanda por alimentos, é importante estabelecer um melhor aproveitamento da área de cultivo, objetivando a colheita de produtos agrícolas em maior quantidade e de melhor qualidade. O aumento da concentração de micronutrientes nos produtos colhidos, especialmente de zinco é um desafio crescente para a agricultura, com possibilidade de trazer benefícios à saúde humana e à produtividade da cultura. Nesse sentido, a aplicação foliar de zinco realizada periodicamente, à partir da antese floral, é uma técnica capaz de incrementar o teor do micronutriente nas sementes e biofortificar os grãos de feijão e trigo, causando melhoria de aspectos agronômicos (crescimento vegetativo e produtividade da cultura) de plantas provenientes dessas sementes, além de resultar proveitos para a saúde humana daqueles que se alimentam de produtos biofortificados, e ainda com potencial para produzir grãos e sementes como produtos de maior valor comercial no mercado, valendo-se de inovação tecnológica. Porém, atualmente pouco se conhece sobre os diversos aspectos desta técnica. Assim sendo, objetivou-se: (i) elucidar o efeito da aplicação foliar de zinco, à partir da antese floral, como método para incrementar o teor do micronutriente nos grãos de feijão (Phaseolus vulgaris L.) e de trigo (Triticum aestivum L.), em substrato com teor adequado do micronutriente (ii) utilização de diferentes fontes de zinco aplicadas via foliar visando estabelecer a melhor fonte para o aumento do teor do micronutriente no grão de feijoeiro e (iii) determinação das doses de zinco mais adequadas a serem aplicadas através de pulverização foliar visando o aumento do teor do nutriente no grão de plantas de feijão e de trigo. Com base nos resultados obtidos, concluiu-se que (i) a aplicação foliar de zinco realizada periodicamente, à partir da antese floral é capaz de aumentar o teor do micronutriente em grãos de feijão e de trigo; (ii) a fonte mais viável para o enriquecimento de grãos de feijão é o sulfato de zinco; (iii) e todas as doses testadas (125, 250, 375 e 500 g Zn ha-1) aplicadas via foliar na forma de sulfato de zinco foram efetivas para o enriquecimento de grãos de feijão e de trigo, em relação ao controle (0 g Zn ha-1). / In view of the population increase and consequent growth of food demand, it is important to establish a better utilization of the cultivation area, aiming the harvest of agricultural products in greater quantity and of better quality. The increased concentration of micronutrients in products harvested, especially zinc, is a growing challenge for agriculture, with potential to bring benefits to human health and crop productivity. In this matter, the foliar zinc application performed periodically starting at floral anthesis is a technique capable of increasing the micronutrient content in the seeds and biofortifying grains of common bean and wheat, causing agronomic aspects improvement (vegetative growth and crop productivity) of plants derived from these seeds, in addition to bringing benefits to human health of those who feed on biofortified products, and still with potential to produce grains and seeds as products of greater commercial value in the market, being a technological innovation. However, currently little is known about the aspects that circumvent this technique. The objective of this study was: (i) elucidate the effect of foliar application of zinc, starting at floral anthesis, as a method to increase the micronutrient content of common bean (Phaseolus vulgaris L.) and wheat (Triticum aestivum L.) (ii) the use of different sources of zinc applied in a foliar way, in order to establish the best source for increasing the micronutrient content in common bean grains, and (iii) the determination of the most suitable zinc doses, applied by foliar spraying to increase the nutrient content of common bean and wheat plants. Based on the results obtained, it was concluded that (i) the periodic application of zinc foliar application starting at floral anthesis is capable of increasing the micronutrient content in common bean and wheat grains; (ii) the most viable source for the enrichment of bean grains is zinc sulphate; (iii) and all the doses tested (125, 250, 375 and 500 g Zn ha-1) applied via foliar in the form of zinc sulfate were effective for the enrichment of common bean and wheat grains, in relation to the control (0g Zn ha-1).

Iodine is an essential nutrient for humans, which is often not ingested through food in adequate quantities. Currently, Germany is once again one of the countries in which there is an iodine deficiency in the population. Women between the ages of 20 and 40 are particularly affected, a critical situation since pregnant and lactating women have an increased iodine requirement. Iodization of table salt is a widely used prophylactic measure. However, this method is not sufficient and may become less important in the future if further dietary salt reduction occurs, as nutritionists are demanding. Alternative approaches are therefore needed to improve the supply. One of these approaches is the agronomic biofortification of food crops. In this process, iodine is applied via fertilization measures during the cultivation of the plants. This gives the plants the ability to take up the mineral, which is only available in the soil to a very limited extent. In recent years, many studies have been published on the biofortification of vegetables and cereals. Foliar fertilization measures have proven to be significantly more efficient than soil fertilization measures. Nevertheless, up to now few results are available on the biofortification of fruit crops. However, fruit is also important for a healthy diet and the iodine supply of humans can only be improved if as many iodine-rich foods as possible are available. Therefore, the aim of this work was to investigate iodine biofortification of berry and tree fruit species in more detail. In order to be able to achieve this objective, trials were performed over several years with strawberries, apple and pear trees. In addition to suitable application methods, the aim was to determine the iodine form (iodide and iodate) and the necessary iodine quantity. On the one hand, the measured iodine contents in the fruit and leaf tissue allowed conclusions to be drawn about the translocation of iodine in the plant. On the other hand, this made it possible to evaluate the basic suitability for iodine biofortification of the fruit crops investigated. Since iodine has a phytotoxic effect above a certain amount, the plant compatibility should also be tested. In addition, common household processing methods, such as washing or peeling the fruit, as well as fruit storage over several months, should provide information on the extent to which such measures could reduce the iodine content. Another study parameter was the soluble solids content, as there is evidence that iodine can affect the sugar content of fruit. Furthermore, a combined application of potassium nitrate and selenium was carried out and their influence on iodine and sugar content was investigated. Selenium is also an essential trace element, which is usually inadequately absorbed through the diet. The results of the investigations showed that it was possible, in principle, to raise the iodine content of strawberries, apples and pears to a level of 50 to 100 µg iodine per 100 g fresh mass. In the case of strawberries, however, this was only feasible if the plants were in their first year of cultivation and the iodine was applied by foliar fertilization shortly before harvest. In the 2nd and 3rd year of cultivation, the plants had a very dense canopy, which prevented direct wetting of the fruit. However, direct wetting of the fruit surface with the iodine solution is imperative, as this was the only way to achieve a reliably high iodine content in the fruit mass. Soil fertilization proved to be completely unsuitable in trials with strawberries and apple trees. The translocation of iodine after soil fertilization occurred mainly via the xylem transport into the strongly transpiring leaves and not into the fruits. In addition, compared to a foliar application, a significantly higher iodine application rate was required. Furthermore, experiments with apple trees cultivated in a plastic tunnel, protected from precipitation, showed that the iodine transfer via the phloem into the fruits was only marginal. With regard to the phytotoxic effect of iodine application, no consistent difference was observed between potassium iodide and potassium iodate. Both forms of iodine did not affect yield or average individual fruit weight. Damage to fruit was not observed in any variant. However, with increasing iodine levels, significant damage to leaves was noticeable. Apple and pear trees also showed early leaf fall. Iodide generally led to significantly higher iodine contents in the plant mass after foliar application, but this was also associated with high fluctuations. With iodate, it was possible to reliably achieve the targeted iodine content in the fruit mass of apple and pear trees with an application rate of 1.5 kg iodine per hectare and meter canopy height. Washing the fruit reduced the iodine content of strawberries by up to 30%. For apples and pears, this value was about 14% at harvest and about 12% after 3 months of storage. Peeled apples and pears showed a significantly reduced iodine content. 51% of the iodine in apples was bound in the fruit peel or the cuticular waxes. A reduction of 73% was determined for pears. Cold storage for 3 months resulted in a significant loss of iodine in parts of the apple peel. At this point, the release of volatile iodine compounds is probably the cause of the reduction. However, this would still have to be confirmed by further investigations. Iodine application had a negative effect on the soluble solids content of strawberries above a certain level. It was not possible to observe significant changes for pome fruit in the trials conducted. However, the application of potassium nitrate (alone and in combination with iodine) resulted in an increase. Iodine uptake remained unaffected by the combined application of potassium nitrate and selenium. However, it was shown that selenium has a comparable uptake and translocation pattern to iodine and that a combined biofortification with both minerals is, in principle, possible. Accordingly, apple and pear trees are well suited for biofortification with iodine by foliar fertilization. However, further trials in commercial orchards are necessary to implement this process. In the future, appropriately fortified fruit could make an important contribution to the alimentary iodine supply for humans.

The demand for plant and other production is increasing with the growth of human population when the territory where plants can be grown is continually decreasing. The present agricultural production of food, industrial materials and drugs of plant origin is not enough for people, as for the effort to achieve higher environmental comfort, especially in developed countries. We are trying to find a simpler, cleaner and cheaper ways of crop production. The genetic modification is one of the modern ways how to achieve this goal. Students get a lot of information about this topic from various sources, but mainly just from the internet and television. It is recommended that students should be able to compare information received from the media with school knowledge as for avoiding opinion pressure and manipulations.