MORPHOGENESIS AND PRODUCTION OF TANZANIA, MOMBACA AND MULATO GRASSES UNDER NITROGEN FERTILIZATION

A field trial was conducted designed in a completely randomized block in a 4 x 3 factorial arrangement to evaluate the application of nitrogen doses (N) (0, 40, 80 and 160 kg/ha) on the morphogenical characteristics and dry matter partition of three forage grasses (Panicum maximum cvs. Mombasa and Tanzania and Brachiaria sp. Hybrid Mulato). The leaf appearance (LAR, leaf/day) and stretching (LER; mm/day) rates, the number of green leaves per tiller (NLT) and the average weight of tillers (MTW; g) presented s positive linear response to the N dose while the phyllochron (Phil; day/leaves) showed a negative linear response. The highest LER, IAL and final leaf length (FLL; cm) occurred in the Mombaca and Tanzania grasses, while the highest LAR occurred in the Mulato grass. There was a negative quadratic effect of the N dose on the stem elongation rate (SER; mm/day) and LF. The Mombaca and Tanzania grasses presented the highest SER; however, in just two forages. The production of total dry matter (TDM; kg/ha), leaves (LDM; kg/ha) and stems (SDM; kg/ha) increased linearly and quadratically with the N dose, respectively, for the Mombaca and Tanzania grasses. There was a high positive correlation among DM, LDM and SDM and the Mombaca grass MTW. The dry matter production and morphogenic characteristics were influenced by the nitrogen fertilization as a result of the substantial increase in the flow of tissues stimulated by fertilization, proving the importance of N for forage biomass accumulation.

Resposta da soqueira da cana-de-açúcar à aplicação de nitrogênio na ausência e na presença de silício

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Fontes e manejo de nitrogênio na cultura da batata em solos arenosos

Pós-graduação em Agronomia (Agricultura) - FCA

Resposta da terceira soqueira da cana-de-açúcar à aplicação de nitrogênio na presença e ausência de silício

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Sistemas de cultivo antecessores e doses de nitrogênio em cobertura no feijoeiro em plantio direto = cover crop systems and nitrogen topdressing on common bean in no tillage

The objective of this work was to evaluate the grass cover crop production in crop systems involving maize and Urochloa ruziziensis, and the influence of topdressing nitrogen rates in the yield and agronomic efficiency on common-bean cultivated in succession in no-tillage. The experiments were conducted in Jaboticabal-SP, in a eutrophic red latosol, in the second year of no-tillage system implementation. The IPR 139 cultivar was used in split plot design with three replications, in randomized block. The plots had been composed for three crop systems in the summer season, with maize exclusive, maize intercropped with U. ruziziensis and U. ruziziensis exclusive. The subplots had been constituted for five nitrogen rates (0, 40, 80, 120 and 160 kg ha(-1)), applied as topdressing at V4-4 in irrigated common-bean cultivated in the winter-spring season. The use of U. ruziziensis in crops systems, exclusive or intercropped with maize favors the grass cover crop production sufficiently to total soli surface covered, possibility similar grain yield compared to maize exclusive. The topdressing nitrogen application doesn't affect the common-bean yield in succession to maize and U. ruziziensis intercropped. The increase of nitrogen rates in common-bean in succession to maize exclusive improves the yield, although decreases the agronomic efficiency.

Adubação orgânica e fertirrigação potássica em videira Syrah no Semiárido

Apesar da grande importância da adubação na qualidade das uvas, ainda existem poucos estudos sobre a fertirrigação em videira de vinho no Vale do Submédio São Francisco. Com o objetivo de avaliar a produção de uvas sob a influência de doses de potássio e de adubo orgânico, um experimento foi realizado na Embrapa Semiárido, em Petrolina-PE, com videiras (Vitis vinifera L.), ‘Syrah’, enxertadas sobre o porta-enxerto ‘Paulsen’ 1103 e cultivadas no espaçamento 3 x 1 m. As plantas foram irrigadas por um sistema de gotejamento, com um emissor por planta, com vazão de 2 L h¹. Os tratamentos foram constituídos de cinco doses de potássio (0, 20, 40, 80 e 160 kg ha¹) e duas doses de adubo orgânico (0 e 7,5 m³ qual o adubo orgânico constituiu as parcelas e as doses de potássio as subparcelas. Foram avaliados na colheita o número de cachos por planta, a produção total por planta, o peso médio dos cachos e o rendimento total das plantas. As diferentes doses de potássio aplicadas pelo sistema de irrigação e de adubo orgânico aplicados via solo não influenciaram significativamente as características avaliadas.

Avaliação de atributos físico-químicos do solo sobre palhadas de diferentes poáceas e adubação nitrogenada em semeadura direta na cultura do feijoeiro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Assessing biophysical variable parameters of bean crop with hyperspectral measurements

Recently high spectral resolution sensors have been developed, which allow new and more advanced applications in agriculture. Motivated by the increasing importance of hyperspectral remote sensing data, the need for research is important to define optimal wavebands to estimate biophysical parameters of crop. The use of narrow band vegetation indices (VI) derived from hyperspectral measurements acquired by a field spectrometer was evaluated to estimate bean (Phaseolus vulgaris L.) grain yield, plant height and leaf area index (LAI). Field canopy reflectance measurements were acquired at six bean growth stages over 48 plots with four water levels (179.5; 256.5; 357.5 and 406.2 mm) and tree nitrogen rates (0; 80 and 160 kg ha-1) and four replicates. The following VI was analyzed: OSNBR (optimum simple narrow-band reflectivity); NB_NDVI (narrow-band normalized difference vegetation index) and NDVI (normalized difference index). The vegetation indices investigated (OSNBR, NB_NDVI and NDVI) were efficient to estimate LAI, plant height and grain yield. During all crop development, the best correlations between biophysical variables and spectral variables were observed on V4 (the third trifoliolate leaves were unfolded in 50 % of plants) and R6 (plants developed first flowers in 50 % of plants) stages, according to the variable analyzed.

Different approaches to identify markers for meat quality and production traits in pigs: analysis of the transcriptome in post mortem skeletal muscle and investigation of candidate genes

Due to the growing attention of consumers towards their food, improvement of quality of animal products has become one of the main focus of research. To this aim, the application of modern molecular genetics approaches has been proved extremely useful and effective. This innovative drive includes all livestock species productions, including pork. The Italian pig breeding industry is unique because needs heavy pigs slaughtered at about 160 kg for the production of high quality processed products. For this reason, it requires precise meat quality and carcass characteristics. Two aspects have been considered in this thesis: the application of the transcriptome analysis in post mortem pig muscles as a possible method to evaluate meat quality parameters related to the pre mortem status of the animals, including health, nutrition, welfare, and with potential applications for product traceability (chapters 3 and 4); the study of candidate genes for obesity related traits in order to identify markers associated with fatness in pigs that could be applied to improve carcass quality (chapters 5, 6, and 7). Chapter three addresses the first issue from a methodological point of view. When we considered this issue, it was not obvious that post mortem skeletal muscle could be useful for transcriptomic analysis. Therefore we demonstrated that the quality of RNA extracted from skeletal muscle of pigs sampled at different post mortem intervals (20 minutes, 2 hours, 6 hours, and 24 hours) is good for downstream applications. Degradation occurred starting from 48 h post mortem even if at this time it is still possible to use some RNA products. In the fourth chapter, in order to demonstrate the potential use of RNA obtained up to 24 hours post mortem, we present the results of RNA analysis with the Affymetrix microarray platform that made it possible to assess the level of expression of more of 24000 mRNAs. We did not identify any significant differences between the different post mortem times suggesting that this technique could be applied to retrieve information coming from the transcriptome of skeletal muscle samples not collected just after slaughtering. This study represents the first contribution of this kind applied to pork. In the fifth chapter, we investigated as candidate for fat deposition the TBC1D1 [TBC1 (tre-2/USP6, BUB2, cdc16) gene. This gene is involved in mechanisms regulating energy homeostasis in skeletal muscle and is associated with predisposition to obesity in humans. By resequencing a fragment of the TBC1D1 gene we identified three synonymous mutations localized in exon 2 (g.40A>G, g.151C>T, and g.172T>C) and 2 polymorphisms localized in intron 2 (g.219G>A and g.252G>A). One of these polymorphisms (g.219G>A) was genotyped by high resolution melting (HRM) analysis and PCR-RFLP. Moreover, this gene sequence was mapped by radiation hybrid analysis on porcine chromosome 8. The association study was conducted in 756 performance tested pigs of Italian Large White and Italian Duroc breeds. Significant results were obtained for lean meat content, back fat thickness, visible intermuscular fat and ham weight. In chapter six, a second candidate gene (tribbles homolog 3, TRIB3) is analyzed in a study of association with carcass and meat quality traits. The TRIB3 gene is involved in energy metabolism of skeletal muscle and plays a role as suppressor of adipocyte differentiation. We identified two polymorphisms in the first coding exon of the porcine TRIB3 gene, one is a synonymous SNP (c.132T> C), a second is a missense mutation (c.146C> T, p.P49L). The two polymorphisms appear to be in complete linkage disequilibrium between and within breeds. The in silico analysis of the p.P49L substitution suggests that it might have a functional effect. The association study in about 650 pigs indicates that this marker is associated with back fat thickness in Italian Large White and Italian Duroc breeds in two different experimental designs. This polymorphisms is also associated with lactate content of muscle semimembranosus in Italian Large White pigs. Expression analysis indicated that this gene is transcribed in skeletal muscle and adipose tissue as well as in other tissues. In the seventh chapter, we reported the genotyping results for of 677 SNPs in extreme divergent groups of pigs chosen according to the extreme estimated breeding values for back fat thickness. SNPs were identified by resequencing, literature mining and in silico database mining. analysis, data reported in the literature of 60 candidates genes for obesity. Genotyping was carried out using the GoldenGate (Illumina) platform. Of the analyzed SNPs more that 300 were polymorphic in the genotyped population and had minor allele frequency (MAF) >0.05. Of these SNPs, 65 were associated (P<0.10) with back fat thickness. One of the most significant gene marker was the same TBC1D1 SNPs reported in chapter 5, confirming the role of this gene in fat deposition in pig. These results could be important to better define the pig as a model for human obesity other than for marker assisted selection to improve carcass characteristics.

Study of Candidate Genes for production and carcass traits in Italian Heavy Pigs: identification of a new DNA Markers, Expression Studies and Association Analysis using Different Experimental Design

Heavy pig breeding in Italy is mainly oriented for the production of high quality processed products. Of particular importance is the dry cured ham production, which is strictly regulated and requires specific carcass characteristics correlated with green leg characteristics. Furthermore, as pigs are slaughtered at about 160 kg live weight, the Italian pig breeding sector faces severe problems of production efficiency that are related to all biological aspects linked to growth, feed conversion, fat deposition and so on. It is well known that production and carcass traits are in part genetically determined. Therefore, as a first step to understand genetic basis of traits that could have a direct or indirect impact on dry cured ham production, a candidate gene approach can be used to identify DNA markers associated with parameters of economic importance. In this thesis, we investigated three candidate genes for carcass and production traits (TRIB3, PCSK1, MUC4) in pig breeds used for dry cured ham production, using different experimental approaches in order to find molecular markers associated with these parameters.

N budget and NH3 exchange of a grass/clover crop at two levels of N application

Atmospheric ammonia (NH3) exchange during a single growing season was measured over two grass/clover fields managed by cutting and treated with different rates of mineral nitrogen (N) fertilizer. The aim was to quantify the total NH3 exchange of the two systems in relation to their N budget, the latter was split into N derived from symbiotic fixation, from fertilization, and from the soil. The experimental site was located in an intensively managed agricultural area on the Swiss plateau. Two adjacent fields with mixtures of perennial ryegrass (Lolium perenne L.), cocks foot (Dactylis glomerata L.), white clover (Trifolium repens L.) and red clover (Trifolium pratense L.) were used. These were treated with either 80 or 160 kg N ha−1 applied as NH4NO3 fertilizer in equal portions after each of four cuts. Continuous NH3 flux measurements were carried out by micrometeorological techniques. To determine the contribution of each species to the overall NH3 canopy compensation point, stomatal NH3 compensation points of the individual plant species were determined on the basis of NH4+ + NH3 (NHx) concentrations and pH in the apoplast. Symbiotic N2 fixation was measured by the 15N dilution method.

Optimización del Abonado Nitrogenado en el Melón (Cucumis Melo L.) Tipo Piel de Sapo

Spain is the fifth-largest producer of melon (Cucumis melo L.) and the second exporter in the world. To a national level, Castilla-La Mancha emphasize and, specifically, Ciudad Real, where is cultivated 27% of national area dedicated to this crop and 30% of melon national production. Melon crop is cultivating majority in Ciudad Real and it is mainly located in the Alto Guadiana, where the major aquifers of the region are located, the aquifer 23 or Mancha Occidental and the aquifer 24 or Campo de Montiel, both declared overexploited and vulnerable zones to nitrate pollution from agricultural sources. The problem is exacerbated because in this area, groundwater is the basic resource of supply to populations, and even often the only one. Given the importance of melon in the area, recent research has focused on the irrigation of melon crop. Unfortunately, scant information has been forthcoming on the effect of N fertilizer on melon piel de sapo crop, so it is very important to tackle in a serious study that lead to know the N requirements on the melon crop melon by reducing the risks of contamination by nitrate leaching without affecting productivity and crop quality. In fact, the recommended dose is often subjective and practice is a N overdose. In this situation, the taking of urgent measures to optimize the use of N fertilization is required. To do it, the effect of N in a melon crop, fertirrigated and on plastic mulch, was studied. The treatments consisted in different rates of N supply, considering N fertilizer and N content in irrigation water, so the treatment applied were: 30 (N30), 85 (N85), 112 (N112) and 139 (N139) Kg N ha-1 in 2005; 93 (N93), 243 (N243) and 393 (N393) kg ha-1 in 2006; and 11 (N11), 61 (N61), 95 (N95) and 148 (N148) kg ha-1 in 2007. A randomized complete-block design was used and each treatment was replicated four times. The results showed a significant effect of N on dry biomass and two patterns of growth were observed. On the one hand, a gradual increase in vegetative biomass of the plant, leaves and stem, with increasing N, and on the other hand, an increase of fruit biomass also with increasing N up to a maximum of biomass corresponding to the optimal dose determined in 90 kg ha-1 of N applied, corresponding to 160 kg ha-1 of N available for melon crop, since this optimum dose, the fruit biomass suffers a decline. A significant effect was observed in concentration and N uptake in leaf, steam, fruit and whole plant, increasing in all of them with increasing of N doses. Fast N uptake occurred from 30-35 to 70-80 days after transplanting, coinciding with the fruit development. The N had a clear influence on the melon yield, its components, skin thickness and flesh ratio. The melon yield increased, as the mean fruit weight and number of fruits per m2 with increasing N until achieve an above 95% of the maximum yield when the N applied is 90 kg ha-1 or 160 kg ha-1 of N available. When N exceeds the optimal amount, there is a decline in yield, reducing the mean fruit weight and number of fruits per square meter, and was also observed a decrease in fruit quality by increasing the skin thickness and decrease the flesh ratio, which means an increase in fruit hollowed with excessive N doses. There was a trend for all indexes of N use efficiency (NUE) to decline with increasing N rate. We observed two different behaviours in the calculation result of the NUE; on the one hand, all the efficiency indexes calculated with N applied and N available had an exponential trend, and on the other hand, all the efficiency indexes calculated with N uptake has a linear trend. The linear regression cuts the exponential curve, delimiting a range within which lies the optimum quantity of N. The N leaching as nitrates increased exponentially with the amount of N. The increase of N doses was affected on the N mineralization. There was a negative exponential effect of N available on the mineralization of this element that occurs in the soil during the growing season, calculated from the balances of this element. The study of N leaching for each N rate used, allowed to us to establish several environmental indices related to environmental risk that causes the use of such doses, a simple way for them to be included in the code of Best Management Practices.

Nitrogen Fertirrigation: an Integrated Agronomic and Environmental Study

Proper management of the N applied to crops is necessary in order to increase yield, improve water use efficiency (WUE) and reduce the pollutions risks with the least economic, environmental and health costs. A field study with melon crops was conducted during 2005, 2006 and 2007 in central Spain, using 11 different amounts of N. Some environmental indexes have been proposed, to provide an essential tool for determining the groundwater pollution risks associated with common agricultural practices. These indexes are related to variation in the nitrate concentration of drinking water (Impact Index (II)) and groundwater (Environmental Impact Index (EII)). Also, the Management Efficiency (ME) was calculated, which is related to the amount of fruit produced per gram of N leached (Nl). To determine the optimum dose of N, it was also necessary to know the N mineralisation (NM). Our results show that 160 kg ha?1 of available N (Nav) produced the maximum fruit yield (FY), enhanced WUE and gave an NM of 85 kg ha?1, while the impact indexes did not exceed the fixed maximum allowable limits and ME was adequate. The proposed indexes proved to be an effective tool for determining the risk of nitrate contamination and confirmed that the optimum dose of N corresponded to the maximum FY with minimal loss of Nl.

Nitrogen fertigation: An integrated agronomic and environmental study

Proper management of the N applied to crops is necessary in order to increase yield, improve water use efficiency (WUE) and reduce the pollutions risks with the least economic, environmental and health costs. A field study with melon crops was conducted during 2005, 2006 and 2007 in central Spain, using 11 different amounts of N. Some environmental indexes have been proposed, to provide an essential tool for determining the groundwater pollution risks associated with common agricultural practices. These indexes are related to variation in the nitrate concentration of drinking water (Impact Index (II)) and groundwater (Environmental Impact Index (EII)). Also, the Management Efficiency (ME) was calculated, which is related to the amount of fruit produced per gram of N leached (Nl). To determine the optimum dose of N, it was also necessary to know the N mineralisation (NM). Our results show that 160 kg ha−1 of available N (Nav) produced the maximum fruit yield (FY), enhanced WUE and gave an NM of 85 kg ha−1, while the impact indexes did not exceed the fixed maximum allowable limits and ME was adequate. The proposed indexes proved to be an effective tool for determining the risk of nitrate contamination and confirmed that the optimum dose of N corresponded to the maximum FY with minimal loss of Nl.

Avaliação da fertilização azotada na produtividade e qualidade da variedade Hermes para indústria

O azoto é determinante na produtividade e na qualidade da batata para indústria. Com este trabalho pretendeu-se avaliar o efeito de diferentes doses de azoto na variedade de batata “Hermes”, em plena condições de cultivo do Vale do Tejo. Os tratamentos consistiram na aplicação de 0 (N0), 80 (N80), 160 (N160), 240 (N240) e 320 (N320) kg de azoto/ha, na forma de ENTECÒ 26. O ensaio foi instalado em parcelas totalmente aleatórias, com 4 repetições. Foi registado semanal a taxa de cobertura de solo pelo método da grelha até à sua cobertura total. Bissemanalmente, foram recolhidas plantas nos tratamentos N0 (0kgN/ha) e N160 (160kgN/ha) para avaliação do seu desenvolvimento e crescimento. No final do ciclo cultural avaliou-se a produção total, comercial, em peso e número de tubérculos. Avaliou-se ainda o peso específico, os teores em matéria seca dos tubérculos e a percentagem do azoto total na matéria seca das folhas e tubérculos. A adubação azotada influenciou a dimensão do aparelho fotossintético, através do estímulo de ramificações. Verificou-se uma maior produtividade de tubérculos nos tratamentos com maior aplicação de azoto, embora os acréscimos tenham sido menores a partir dos 160kg/ha. O azoto influenciou a percentagem de tubérculos de maior calibre.