<p>Prinos zrna predstavlja jednu od najznačajnijih i najsloženijih osobina u oplemenjivanju biljaka. Poznavanje razvića, rastenja i akumulacije suve materije, omogućava pravilan odabir genotipova i odgovarajuće tehnologije gajenja. Cilj istraživanja je bio da se izvr&scaron;i ispitivanje filohrona, akumulacije i translokacije suve materije nadzemnog dela biljaka, prinosa zrna i komponenti prinosa, različitih genotipova ozime p&scaron;enice i ječma sejanih u vi&scaron;e rokova setve i vegetacionih sezona. Zatim da se utvrdi odgovarajuća jednačina koja opisuje akumulaciju suve materije i pojavu listova na glavnom stablu ječma i p&scaron;enice u funkciji sume temperatura tokom različitih rokova setve i vegetacionih sezona. U ogled je bilo uključeno po &scaron;est genotipova ozimog dvoredog ječma i ozime p&scaron;enice različitog porekla, pedigrea i agronomskih osobina, sejanih dve sezone u četiri roka setve. Sredinom cvetanja i u punoj zrelosti, uzeto je 10 slučajno odabranih biljaka. Na uzetim biljkama određena je masa pojedinačnih organa i komponente prinosa, kao i translokacija suve materije i doprinos asimilata akumuliranih pre cvetanja u masi zrna. Za utvrđivanje filohrona i ukupnog broja listova, dva puta nedeljno se očitavao broj listova na obeleženim biljkama tokom čitave sezone. Istovremeno se uzimao i uzorak od pet biljaka u cilju praćenja akumulacije suve materije. Sezona, rok setve i sorta su imali značajan uticaj na variranje ukupnog broja listova i filohrona kod ječma i p&scaron;enice. U proseku, sorte ječma su formirale vi&scaron;e listova u odnosu na p&scaron;enicu, dok se p&scaron;enica karakteri&scaron;e dužim filohronom. Kasnija setva dovela je do značajnog smanjenja broja listova i skraćenja filohrona kod obe vrste. U zavisnosti od sezone, roka setve, sorte i njihove interakcije menjala se i biomasa biljaka u cvetanju i prinos zrna. Translokacija suve materije je bila u pozitivnoj korelaciji sa biomasom biljaka u cvetanju. Akumulacija biomase nadzemnog dela biljaka tokom sezone, pratila je tipičan sigmoidni obrazac u svim kombinacijama rokova setve i sorti. Od tri posmatrane nelinearne jednačine, Logistička jednačina se pokazala najprikladnijom za opisivanje akumulacije suve<br />materije tokom sezone kod ječma i p&scaron;enice. Rezultati istraživanja ukazuju na značaj vegetativne mase biljaka u cvetanju, koja predstavlja bitan izvor asimilata za translokaciju u zrno. Ovi rezultati ukazuju da je tokom oplemenjivanja strnih žita, neophodno stvarati genotipove sa većim brojem listova koji bolje nakupljaju biomasu, odnosno genotipove koji će u optimalnom roku setve, imati usklađen fenolo&scaron;ki razvoj sa agroekolo&scaron;kim uslovima u području Panonske nizije.</p> / <p>Grain yield is one of the most important and complex traits in plant breeding. Knowledge about crop development, growth and dry matter accumulation enables the appropriate selection of genotypes and field technology. The aims of this study were to investigate the variability of phyllochron, dry matter accumulation and translocation, grain yield and yield components of various wheat and barley genotypes, in relation to the sowing date and growing season. Furthermore, the goal was to find the equation that would appropriately describe dry matter accumulation and leaf appearance of wheat and barley. Six winter barley and six winter wheat genotypes, characterized by different origin, pedigree and agronomic traits, were sown in two growing seasons across four sowing dates. At the anthesis and physiological maturity, 10 randomly selected plants were manually cut at ground level. Dry mass of different plant organs, yield components, dry matter translocation and contribution of pre-heading dry matter to grain yield were determined. To determine the leaf number and phyllochron, measuring was done according to the Haun scale on three tagged plants per replication three times per week. Also, samples consisting of five plants were collected to determine dry matter accumulation. Growing season, sowing date and variety had significant influence on the final leaf number and phyllochron of wheat and barley. At average, barley varieties had more leaf compared to wheat, while wheat had higher phyllochron values. Late sowing reduced the final leaf number and phyllochron in both barley and wheat. Furthermore, growing season, sowing date, variety and sowing date &times; variety interaction had significant influence on crop biomass at anthesis and grain yield. Dry matter translocation was in positive correlation with dry matter content at anthesis. Dry matter accumulation across growing seasons had a typical sigmoid pattern in every combination of sowing date and variety. Among studied models, the logistic equation was the most appropriate for description of dry matter accumulation in wheat and barley. Results from this study highlight the importance of dry matter content at anthesis, which represent a significant source of assimilates for translocation into the grain. These results indicated that during the selection of small grain cereals, it is necessary to develop genotypes characterized by higher leaf number and increased biomass, i.e. genotypes that in optimal sowing dates, have an adjusted phenological development to the agro-ecological conditions of the Panonian plane.</p>

Made available in DSpace on 2015-03-26T13:39:52Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1923841 bytes, checksum: 6546cf1460a88bdf741cf76afb6b98ed (MD5) Previous issue date: 2012-10-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work examines the accumulation of nutrients of the lulo plants under field conditions. The work was carried out from November 2010 to July 2011, at the precipice orchard belonging to the Federal University of Viçosa, in Viçosa, Minas Gerais State, Brazil. The experimental design was in randomized complete blocks with four replications. The treatment consisted of fifteen collection dates, beginning 30 days after transplanting (DAT), at 15 day intervals. The collected plants were fractionated into leaves, stems and fruits, dried and subjected to determination of nutrients concentration (N, P, K, Ca, Mg, S, Fe, Cu, Zn, and Mn). From the concentration of this nutrients and dry mass of the leaves, stem and fruits, it was determined the accumulation of nutrients in different parts of plants and total plant in each time. It was evaluated: dry matter accumulation in leaves, branches, fruits and total. The fruits provided higher production of dry mass in comparation to other organs. In the crop, at 240 days after transplanting (DAT), 45% of dry matter was allocated in the fruits 35% in the leaves and 20% in the stem. N and Fe were the macro and Micronutrients more absorved on the plant. The order of accumulation of nutrients was 28,684; 23,182; 9,148; 3,762; 1,846; 1,736 g.planta-1, respectively, for K, N, Ca, Mg, P, S e 442, 67; 80, 56; 30, 76; 6,63 mg.planta-1, respectively for Fe, Mn, Zn, Cu. The nutrients N, K, P, Ca, S and Cu accumulated preferentially in the fruits, while Mg, Fe, Zn and Mn accumulated in vegetative part. The period of large absorption of N and K of plants lulo was between 165 and 240 day after transplanting date, respectively. / Este trabalho teve como objetivo determinar o acúmulo de nutrientes pela cultura de lulo desenvolvida em condições de campo. O trabalho foi realizado no período de novembro de 2010 a julho de 2011, no pomar do Fundão pertencente a Universidade Federal de Viçosa, no município de Viçosa, Estado de Minas Gerais, Brasil. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições. Os tratamentos consistiram em quinze épocas de coletas iniciadas aos 30 dias após o transplantio, com intervalo entre coletas de 15 dias. As plantas coletadas foram fracionadas em folhas, caule e frutos; secas e submetidas a determinação das concentrações de nutrientes (N, P, K, Ca, Mg, S, Fe, Cu, Zn e Mn). A partir das concentrações desses nutrientes, e da massa seca de folhas, caule e frutos determinou-se o acúmulo de nutrientes em cada época. Foram avaliados: acúmulo de massa seca nas folhas, caule, frutos e total. Aos 240 dias após o transplantio (DAT), 45% da massa seca alocou-se nos frutos, 35% no caule e 20% nas folhas. O K e o Fe foram os macro e micronutrientes mais absorvidos pela planta. O acúmulo de nutrientes pelas plantas de lulo por ordem decrescente foi de 28,684; 23,182; 9,148; 3,762; 1,846; 1,736 g.planta-1, respectivamente para K, N, Ca, Mg, P, S e 442, 67; 80,56; 30,76; 6,63 mg.planta-1, respectivamente para Fe, Mn, Zn, Cu. Os nutrientes N, K, P, Ca, S e Cu acumularam-se preferencialmente nos frutos, enquanto Mg, Zn, Mn e Fe na parte vegetativa. O período de maior absorção de N e K pelas plantas de lulo foi entre 165-240 dias após o transplantio.

Orientadora: Ana Cláudia Ruggieri / Banca: André Fischer Sbrissia / Banca: Kleber Tomás de Resende / Resumo: A produção de forragem é influenciada pelas estratégias de manejo impostas a ela, desta maneira, as técnicas para identificação do melhor momento para início e término do pastejo, aliadas aos estudos das características morfogênicas e estruturais das plantas, tornam-se úteis para direcionamento do manejo, pois buscam auxiliar no melhor entendimento do crescimento vegetal, e por conseqüência, da produção forrageira. O experimento foi realizado no setor de Forragicultura, em área pertencente à FCAV da UNESP - Jaboticabal no período de dezembro de 2008 a abril de 2009, com o objetivo de avaliar o efeito de índices de área foliar residual (IAFr) sobre as características morfogênicas e estruturais, além do acúmulo de forragem em pastos de Cynodon spp cv Tifton-85 sob regime de lotação rotacionada com ovinos. Os tratamentos foram constituídos por três IAFr, 2,4, 1,6 e 0,8, mantidos por regime de lotação rotacionada com ovinos. O delineamento experimental utilizado foi o de blocos completos casualizados em arranjo de parcelas subdivididas no tempo com sete repetições, totalizando 21 unidades experimentais. Foram avaliadas nas condições de pré e pós-pastejo, as alturas do dossel, os IAF e a massa de forragem, além da taxa de acúmulo de forragem e as características morfogênicas e estruturais dos pastos. No pré e pós-pastejo as alturas médias e o IAF do dossel se comportaram de forma análoga, decrescendo com a diminuição dos IAFr. O maior valor de interceptação luminosa no pós-pastejo (68,19%), foi verificado para o IAFr 2,4 e o menor valor (35,57%) para o IAFr 0,8. A taxa de aparecimento de folhas foi maior para o dossel mantido sob IAFr 0,8 em função da sua menor taxa de alongamento de colmos (0,51 cm/perfilho.dia). Os pastos mantidos sob IAFr 0,8 apresentaram maior densidade populacional de perfilhos. A massa de forragem seca... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The production of forage is influenced by handling strategies imposed on the techniques to identify the best moment for the beginning and ending of grazing, linked to the studies of morphogenetic and structural characteristics of plants, become useful tools for the directing of management for they aim to aid the best understanding of vegetal growth, and as consequence, forage plants. The experiment was conducted at Setor de Forragicultura at Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, at UNESP - Jaboticabal from December 2008 to April 2009, and aimed to evaluate the effect of residual leaf area index (LAIr) about the morphogenical and structural characteristics, and forage accumulation in pastures of Cynodon spp cv Tifton-85 in a rotational stocking system with sheep. The treatments were constituted by three LAIr, 2,4, 1,6 e 0,8, maintained by rotational stocking with sheep. A complete randomized block design was used arranged in sub-divided parcels with seven replications, totaling 21 experimental units. They were evaluated in pre and post-grazing conditions, the height of the sward, LAI and forage mass, besides the accumulation of forage rate and the morphogenetic and structural characteristics. In the pre and post-grazing, the average height and the LAI of sward, decreasing with the diminishing of LAIr. The biggest value of light interception in post-grazing (68,19%), was verified by LAIr 2,4 and the smallest value (35,57%) for LAIr 0,8. The stem elongation rate (0,51 cm/tiller.day). The grazing maintained by LAIr 0,8 had higher tiller population density. The total dry forage mass was 27,1% superior for LAIr 2,4 regarding to LAIr 0,8 in pre-grazing conditions, being this total production, 72,0% was composed by stem fractions and dead material. The biggest rates of dry matter accumulation were observed with LAIr 2.4, in the second and third grazing cycles... (Complete abstract click electronic access below) / Mestre

Destacam-se as semelhanças entre os nutrientes boro (B) e cálcio (Ca) quanto às formas e as funções que eles exercem nos vegetais. Partindo do princípio que a interação Ca - B afeta os atributos morfológicos, ultraestruturais e bioquímicos, bem como a nodulação nas plantas leguminosas, objetivou-se com esse estudo determinar a relação Ca:B mais adequada para a produção de grãos e matéria seca de soja, bem como avaliar os efeitos da interação B e Ca na fixação biológica de N2 (atividade da nitrogenase -N-ase [EC 1.18.6.1]), na morfologia de raízes (comprimento e superfície total), anatomia de raízes (nódulos) e de folhas, assim como as avaliações ultraestruturais dos mesófilos foliares, rendimento do teor de óleo nos grãos das plantas de soja (cultivar BRS 284), crescidas em solução nutritiva. Foram avaliadas ainda a produção de massa seca das plantas, as concentrações e os acúmulos de Ca, B, Mg, K e N na parte aérea e raízes. Foi empregado um esquema fatorial 5² incompleto, perfazendo treze combinações de doses de Ca (mmol L-1) e B (µmol L-1), as quais foram distribuídas segundo o delineamento experimental de blocos ao acaso, com quatro repetições. As maiores atividades da N-ase foram obtidas com as maiores doses de Ca e B (7,25 mmol L-1 de Ca e 50 µmol L-1 de B). A menor dose de Ca resultou na inibição da N-ase em cerca de 90%. Os maiores comprimentos e superfícies totais de raízes foram obtidos na combinação de doses de 7,25Ca e 12,5B, enquanto que para a combinação das menores doses de Ca e B observou-se uma redução de cerca de 70% e 60% para comprimento e superficial de raízes, respectivamente. A maior produção de biomassa seca das plantas e de grãos, os maiores acúmulos de Ca, B, N, K e Mg nas folhas e o maior rendimento de óleo foram obtidos com o fornecimento de 4,25 mmol L-1 de Ca e 12,5 µmol L-1 de B, observando-se relação Ca:B na solução nutritiva próxima de 350:1 e nas folhas de 700:1. O teor de óleo nos grãos incrementou cerca de 20% com o aumento das doses de B de 3,125 para 50 µmol L 1. O número de camadas de células do córtex dos nódulos aumentou com o incremento das concentrações de Ca e B na solução. Observou-se ruptura da membrana dos cloroplastos no mesófilo foliar e elevado número de bactérias fixadoras de N2 penetrando o interior dos tecidos nodulares quando as plantas foram submetidas ao menor suprimento de Ca e maior de B. A combinação da menor dose de B junto a maior dose de Ca provocou ruptura da parede celular e o espessamento da lamela média das folhas. O aumento no fornecimento de Ca ameniza os efeitos negativos do baixo suprimento de B na produção de biomassa das plantas e de grãos, no comprimento e superfície de raízes e na atividade da nitrogenase. A relação Ca:B, tanto na solução, quanto no tecido vegetal, não pode ser entendida como parâmetro exclusivo de equilíbrio nutricional / Regarding mineral nutrition of plants, we highlight the similarities between nutrients boron (B) and calcium (Ca) in relation to similar functions they play in plant physiology. However, the mechanisms involved in the interaction between these nutrients are not very well known. Assuming that the interaction Ca - B affects the morphological, ultrastructural and biochemical attributes, as well as the nodulation in leguminous plants, the objective with this study was to determine the optimum Ca:B ratio, in the solution and plan tissue as well for dry matter yield of grain and dry matter of soybean, and to evaluate the effects of B - Ca interaction in the biological N2 fixation (nitrogenase activity - N-ase [EC 1.18.6.1]), root morphology (total root length and total root surface area), root anatomy (nodules), as well as in the ultrastructural evaluation of foliar mesophilic, and yield of oil content of soybean (cultivar BRS 284), grown in nutrient solution. Dry matter yield of plants, Ca-concentrations and amounts of Ca, B, Mg, K and N in shoots and roots were also evaluated. The experimental arrange used was an incomplete 5² factorial, making thirteen combinations of Ca (mmol L-1) and B (µmol L-1) rates, which were set in a randomized block design, with four replications. The highest N-ase activity was obtained with the highest doses of Ca and B (7,25 mmol L-1 of Ca and 50 µmol L-1 of B). The lowest Ca rate resulted in approximately 90% inhibition of N-ase. The highest total root length and total root surface area were obtained with combination of 7,25Ca and 12,5B rates, whereas the combination of the lowest Ca and B rates caused reduction of approximately 70% and 60% on root length and area, respectively. The highest dry matter and grain yield, highest accumulations of Ca, B, N, K and Mg on the leaves and the highest oil content in grains were obtained when 4,25 mmol L-1 of Ca and 12,5 µmol L-1 of B were supplied, resulting in a Ca:B ratio of approximately 350:1 on nutrient solution and 700:1 on leaves. The oil content in grains raised about 20% increasing B rates from 3,125 to 50 µmol L-1. The number of cell layers of nodule cortex raised with increasing Ca and B levels in the solution. It was observed membrane rupture of chloroplasts in leaf mesophyll and high number of N2-fixing bacteria entering the interior of nodular tissues when plants were supplied with the lowest Ca rate (1,75Ca) and the highest B (50B). The combination of the lowest B rate (3,125B) and the highest Ca rate (7,25) caused cell wall rupture and thickening of the middle lamella on the leaves. The increase of Ca levels on the solution mitigates the negative effects of the low B supply in plant biomass and grain yield, in root length and root surface area and in N-ase activity. The Ca:B ratio either in the solution or plant tissue, cannot be understood as an exclusive parameter of nutritional status

Made available in DSpace on 2016-08-12T19:15:22Z (GMT). No. of bitstreams: 1 RomuloMOF_DISSERT.pdf: 1866145 bytes, checksum: 9f9729462fbec5049c6b3e9bb450b4fa (MD5) Previous issue date: 2012-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The cowpea crop has great importance for the Brazilian Northeast, especially for the poorest population. One of the major problems encountered for this crop is drought stress caused by erratic rainfall, coupled with the high temperatures common in this region. The no-tillage system has features, such as reduction of soil water evaporation, higher water retention and lower soil temperature fluctuations, and can be a way to minimize the water stress in a cowpea crop. Thus, this study aims to obtain information on growth, yield components and cowpea yield under moisture stress in no-tillage and conventional crop systems. For this purpose an experiment was conducted at Universidade Federal Rural do Semi-Arido, in a split plot with randomized complete blocks design with four replications, using the cowpea cultivar BRS Guariba, and no-tillage and conventional crop systems treatments. For the dry spells simulation, irrigation systems has been suspended at 34 days after sowing, during the onset of flowering, for periods of 2, 6, 10, 14, 18 and 22 days, after what the irrigation was resumed. To evaluate the effect of the crop systems and moisture stress on growth, samples were taken between 15 and 64 days after sowing, in the treatments with and without irrigation (22 days duration). The evaluation of yield components (pod length, number of grains per pod, number of pods per plant and hundred grains weight) and yield was performed at 70 days after sowing. The tillage systems influenced the leaf area, and stem leaf, pod and plant dry weight. The growth rates were influenced by the plant phenological phase (age) and by water stress. The highest growth rates were achieved in the no-tillage system. Water stress affected negatively all the variables, regardless of tillage system. The no-tillage system was more productive both for the irrigated and the stress treatments. The dry spells periods affected grain yield and all other yield components studied in a negative way, except for the hundred grains weight. Among the systems studied, the no-tillage system provides higher values for the yield components, except for the hundred grains weight / A cultura do feijão-caupi possui grande importância para a região Nordeste, principalmente para a população mais carente. Um dos grandes problemas encontrados para essa cultura é o estresse hídrico, provocado pela irregularidade das chuvas, aliado a altas temperaturas, comuns a esta região. O sistema de plantio direto possui características como redução da evaporação da água do solo, maior retenção do solo e menores oscilações da temperatura, e pode ser uma forma de minimizar o efeito do estresse hídrico para a cultura do feijão-caupi. Deste modo, o presente trabalho se propõe a obter informações relativas ao crescimento, componentes da produção e rendimento de feijão-caupi sob veranico nos sistemas de plantio direto e convencional. Para isso, foi realizado, na Universidade Federal Rural do Semi-Árido, um experimento em delineamento de blocos completos casualizados em parcelas subdivididas com 4 repetições, utilizando-se a cultivar de feijão-caupi BRS Guariba em plantio direto e convencional. Para aplicação do veranico, a irrigação foi suspensa nos sistemas aos 34 dias após a semeadura por períodos de 2, 6, 10, 14, 18 e 22 dias sem irrigação, ocasião em que foi verificado o início do florescimento. Para avaliar o efeito dos sistemas e do veranico no crescimento, foram realizadas coletas entre os 15 e 64 dias após a semeadura, nos tratamentos com e sem irrigação (22 dias de duração). A avaliação dos componentes de produção (comprimento de vagem, número de grãos por vagem, número de vagens por planta e peso de cem grãos) e rendimento de grãos foi realizada aos 70 dias após a semeadura. Os sistemas de plantio influenciam o crescimento da área foliar, da matéria seca do caule, de folhas, de vagens e total do feijão-caupi. Os índices de crescimento são influenciados pela fase fenológica da planta (idade) e pelo estresse hídrico. As maiores taxas de crescimento foram alcançadas no sistema de plantio direto. O estresse hídrico afetanegativamente todas as variáveis avaliadas, independentemente do sistema de plantio. O sistema de plantio direto é mais produtivo do que o convencional quando em irrigação e em condição de estresse. Os períodos de veranico influenciaram o rendimento de grãos e todos os componentes de produção estudados de forma negativa, com exceção do peso de cem grãos. Entre os sistemas estudados, o direto é o que proporciona maiores valores para os componentes de produção, exceto peso de cem grãos

Made available in DSpace on 2016-08-12T19:18:43Z (GMT). No. of bitstreams: 1 RomuloMOF_DISSERT.pdf: 1866145 bytes, checksum: 9f9729462fbec5049c6b3e9bb450b4fa (MD5) Previous issue date: 2012-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The cowpea crop has great importance for the Brazilian Northeast, especially for the poorest population. One of the major problems encountered for this crop is drought stress caused by erratic rainfall, coupled with the high temperatures common in this region. The no-tillage system has features, such as reduction of soil water evaporation, higher water retention and lower soil temperature fluctuations, and can be a way to minimize the water stress in a cowpea crop. Thus, this study aims to obtain information on growth, yield components and cowpea yield under moisture stress in no-tillage and conventional crop systems. For this purpose an experiment was conducted at Universidade Federal Rural do Semi-Arido, in a split plot with randomized complete blocks design with four replications, using the cowpea cultivar BRS Guariba, and no-tillage and conventional crop systems treatments. For the dry spells simulation, irrigation systems has been suspended at 34 days after sowing, during the onset of flowering, for periods of 2, 6, 10, 14, 18 and 22 days, after what the irrigation was resumed. To evaluate the effect of the crop systems and moisture stress on growth, samples were taken between 15 and 64 days after sowing, in the treatments with and without irrigation (22 days duration). The evaluation of yield components (pod length, number of grains per pod, number of pods per plant and hundred grains weight) and yield was performed at 70 days after sowing. The tillage systems influenced the leaf area, and stem leaf, pod and plant dry weight. The growth rates were influenced by the plant phenological phase (age) and by water stress. The highest growth rates were achieved in the no-tillage system. Water stress affected negatively all the variables, regardless of tillage system. The no-tillage system was more productive both for the irrigated and the stress treatments. The dry spells periods affected grain yield and all other yield components studied in a negative way, except for the hundred grains weight. Among the systems studied, the no-tillage system provides higher values for the yield components, except for the hundred grains weight / A cultura do feijão-caupi possui grande importância para a região Nordeste, principalmente para a população mais carente. Um dos grandes problemas encontrados para essa cultura é o estresse hídrico, provocado pela irregularidade das chuvas, aliado a altas temperaturas, comuns a esta região. O sistema de plantio direto possui características como redução da evaporação da água do solo, maior retenção do solo e menores oscilações da temperatura, e pode ser uma forma de minimizar o efeito do estresse hídrico para a cultura do feijão-caupi. Deste modo, o presente trabalho se propõe a obter informações relativas ao crescimento, componentes da produção e rendimento de feijão-caupi sob veranico nos sistemas de plantio direto e convencional. Para isso, foi realizado, na Universidade Federal Rural do Semi-Árido, um experimento em delineamento de blocos completos casualizados em parcelas subdivididas com 4 repetições, utilizando-se a cultivar de feijão-caupi BRS Guariba em plantio direto e convencional. Para aplicação do veranico, a irrigação foi suspensa nos sistemas aos 34 dias após a semeadura por períodos de 2, 6, 10, 14, 18 e 22 dias sem irrigação, ocasião em que foi verificado o início do florescimento. Para avaliar o efeito dos sistemas e do veranico no crescimento, foram realizadas coletas entre os 15 e 64 dias após a semeadura, nos tratamentos com e sem irrigação (22 dias de duração). A avaliação dos componentes de produção (comprimento de vagem, número de grãos por vagem, número de vagens por planta e peso de cem grãos) e rendimento de grãos foi realizada aos 70 dias após a semeadura. Os sistemas de plantio influenciam o crescimento da área foliar, da matéria seca do caule, de folhas, de vagens e total do feijão-caupi. Os índices de crescimento são influenciados pela fase fenológica da planta (idade) e pelo estresse hídrico. As maiores taxas de crescimento foram alcançadas no sistema de plantio direto. O estresse hídrico afetanegativamente todas as variáveis avaliadas, independentemente do sistema de plantio. O sistema de plantio direto é mais produtivo do que o convencional quando em irrigação e em condição de estresse. Os períodos de veranico influenciaram o rendimento de grãos e todos os componentes de produção estudados de forma negativa, com exceção do peso de cem grãos. Entre os sistemas estudados, o direto é o que proporciona maiores valores para os componentes de produção, exceto peso de cem grãos

Destacam-se as semelhanças entre os nutrientes boro (B) e cálcio (Ca) quanto às formas e as funções que eles exercem nos vegetais. Partindo do princípio que a interação Ca - B afeta os atributos morfológicos, ultraestruturais e bioquímicos, bem como a nodulação nas plantas leguminosas, objetivou-se com esse estudo determinar a relação Ca:B mais adequada para a produção de grãos e matéria seca de soja, bem como avaliar os efeitos da interação B e Ca na fixação biológica de N2 (atividade da nitrogenase -N-ase [EC 1.18.6.1]), na morfologia de raízes (comprimento e superfície total), anatomia de raízes (nódulos) e de folhas, assim como as avaliações ultraestruturais dos mesófilos foliares, rendimento do teor de óleo nos grãos das plantas de soja (cultivar BRS 284), crescidas em solução nutritiva. Foram avaliadas ainda a produção de massa seca das plantas, as concentrações e os acúmulos de Ca, B, Mg, K e N na parte aérea e raízes. Foi empregado um esquema fatorial 5² incompleto, perfazendo treze combinações de doses de Ca (mmol L-1) e B (µmol L-1), as quais foram distribuídas segundo o delineamento experimental de blocos ao acaso, com quatro repetições. As maiores atividades da N-ase foram obtidas com as maiores doses de Ca e B (7,25 mmol L-1 de Ca e 50 µmol L-1 de B). A menor dose de Ca resultou na inibição da N-ase em cerca de 90%. Os maiores comprimentos e superfícies totais de raízes foram obtidos na combinação de doses de 7,25Ca e 12,5B, enquanto que para a combinação das menores doses de Ca e B observou-se uma redução de cerca de 70% e 60% para comprimento e superficial de raízes, respectivamente. A maior produção de biomassa seca das plantas e de grãos, os maiores acúmulos de Ca, B, N, K e Mg nas folhas e o maior rendimento de óleo foram obtidos com o fornecimento de 4,25 mmol L-1 de Ca e 12,5 µmol L-1 de B, observando-se relação Ca:B na solução nutritiva próxima de 350:1 e nas folhas de 700:1. O teor de óleo nos grãos incrementou cerca de 20% com o aumento das doses de B de 3,125 para 50 µmol L 1. O número de camadas de células do córtex dos nódulos aumentou com o incremento das concentrações de Ca e B na solução. Observou-se ruptura da membrana dos cloroplastos no mesófilo foliar e elevado número de bactérias fixadoras de N2 penetrando o interior dos tecidos nodulares quando as plantas foram submetidas ao menor suprimento de Ca e maior de B. A combinação da menor dose de B junto a maior dose de Ca provocou ruptura da parede celular e o espessamento da lamela média das folhas. O aumento no fornecimento de Ca ameniza os efeitos negativos do baixo suprimento de B na produção de biomassa das plantas e de grãos, no comprimento e superfície de raízes e na atividade da nitrogenase. A relação Ca:B, tanto na solução, quanto no tecido vegetal, não pode ser entendida como parâmetro exclusivo de equilíbrio nutricional / Regarding mineral nutrition of plants, we highlight the similarities between nutrients boron (B) and calcium (Ca) in relation to similar functions they play in plant physiology. However, the mechanisms involved in the interaction between these nutrients are not very well known. Assuming that the interaction Ca - B affects the morphological, ultrastructural and biochemical attributes, as well as the nodulation in leguminous plants, the objective with this study was to determine the optimum Ca:B ratio, in the solution and plan tissue as well for dry matter yield of grain and dry matter of soybean, and to evaluate the effects of B - Ca interaction in the biological N2 fixation (nitrogenase activity - N-ase [EC 1.18.6.1]), root morphology (total root length and total root surface area), root anatomy (nodules), as well as in the ultrastructural evaluation of foliar mesophilic, and yield of oil content of soybean (cultivar BRS 284), grown in nutrient solution. Dry matter yield of plants, Ca-concentrations and amounts of Ca, B, Mg, K and N in shoots and roots were also evaluated. The experimental arrange used was an incomplete 5² factorial, making thirteen combinations of Ca (mmol L-1) and B (µmol L-1) rates, which were set in a randomized block design, with four replications. The highest N-ase activity was obtained with the highest doses of Ca and B (7,25 mmol L-1 of Ca and 50 µmol L-1 of B). The lowest Ca rate resulted in approximately 90% inhibition of N-ase. The highest total root length and total root surface area were obtained with combination of 7,25Ca and 12,5B rates, whereas the combination of the lowest Ca and B rates caused reduction of approximately 70% and 60% on root length and area, respectively. The highest dry matter and grain yield, highest accumulations of Ca, B, N, K and Mg on the leaves and the highest oil content in grains were obtained when 4,25 mmol L-1 of Ca and 12,5 µmol L-1 of B were supplied, resulting in a Ca:B ratio of approximately 350:1 on nutrient solution and 700:1 on leaves. The oil content in grains raised about 20% increasing B rates from 3,125 to 50 µmol L-1. The number of cell layers of nodule cortex raised with increasing Ca and B levels in the solution. It was observed membrane rupture of chloroplasts in leaf mesophyll and high number of N2-fixing bacteria entering the interior of nodular tissues when plants were supplied with the lowest Ca rate (1,75Ca) and the highest B (50B). The combination of the lowest B rate (3,125B) and the highest Ca rate (7,25) caused cell wall rupture and thickening of the middle lamella on the leaves. The increase of Ca levels on the solution mitigates the negative effects of the low B supply in plant biomass and grain yield, in root length and root surface area and in N-ase activity. The Ca:B ratio either in the solution or plant tissue, cannot be understood as an exclusive parameter of nutritional status

Genotypic differences in growth and yield of two common bean (Phaseolus vulgaris L) cultivars to Rhizobium inoculation and management were investigated. In 2003-04, the two bean cultivars (Scylla and T-49) were combined with three inoculant treatments (strains CC 511 and RCR 3644, and a control of no inoculation), two fertiliser levels (0 and 150 kg N ha⁻¹) and two irrigation treatments (irrigated and rainfed). There was no nodulation on either cultivar. To further investigate the symbiotic relationship, 16 rhizobial isolates, including the two used in the first field experiment, were combined with the cultivar Scylla and evaluated in a greenhouse. Subsequently, five Rhizobium isolates were chosen for further field evaluation, based on signs of early nodulation in the greenhouse trial. The second field experiment in 2004-05 combined the five inoculant strains (RCR 3644, UK 2, H 20, PRF 81, PhP 17 and a control) with two bean cultivars (Scylla and T-49). In the greenhouse, nodule number varied from 7 (UK 2) to 347 (H 441) nodules plant⁻¹ at 51 DAS and from 13 (UK 1) to 335 (CIAT 899) nodules plant⁻¹ at 85 DAS. In 2004-05, in the field, nodulation was also variable, ranging between 1 and approximately 70 nodules plant⁻¹, with higher nodules numbers plant⁻¹ being found on cultivar T-49. Of the isolates used in the field, strains H 20, PRF 81 and PhP 17 produced 70, 25 and 12 nodules plant⁻¹ at 70, 40 and 54 DAS respectively. Nodules formed were of various sizes and more than 80 % were pink to dark red in colour denoting the presence of leghaemoglobin and active N fixation. The remaining nodules were either green or white. The importance of selecting an appropriate cultivar for the growing conditions was highlighted in these experiments. Leaf area index, leaf area duration intercepted radiation and final utilisation efficiency were significantly affected by cultivar. In both seasons cv. T-49 reached maturity (dry seed) before Scylla, while unirrigated plants reached green pod maturity seven days before irrigated plants. Plants of cv. Scylla gave a final TDM of 730 g m⁻²; compared to the 530 g m⁻² produced by T-49. The average growth rate was 7.0 and 5.2 g m⁻² day⁻¹ for Scylla and T-49 respectively (2003-04). Plants receiving 150 kg N ha⁻¹ produced 665 g m⁻² TDM which was 12 % more than was produced by unfertilised plants. The application of 150 kg N ha⁻¹ gave an average growth rate of 6.4 g m⁻² day⁻¹ compared to 5.7 g m⁻² day⁻¹ from plants with no N. Inoculation in the field had no significant effect on TDM in both seasons. Temperature affected growth and DM accumulation. Accumulated DM was highly dependent on cumulative intercepted PAR. Air temperatures below the base temperature (10 °C) affected growth in 2004-05, resulting in plants accumulating just 0.24 g DM MJ⁻¹ PAR during early growth. This increased to 2.26 g DM MJ⁻¹ PAR when the temperature was increased above the base temperature. There was a strong relationship between LAI and intercepted PAR. A LAI of 4.0-4.5 was required to intercept 90-95 % of incident solar radiation. Cultivar significantly (p < 0.001) affected radiation use efficiency (RUE). Scylla had a RUE of 1.02 g DM MJ⁻¹ PAR compared to T-49 at 1.18 g DM MJ⁻¹ PAR. Seed yield was significantly (p < 0.001) affected by cultivar and fertiliser application. Cultivar Scylla produced 467 g m⁻² which was 76 % more than T-49, while a 12 % increase in seed yield was observed in N fertilised plants over unfertilised plants. Only cultivar significantly affected HI, while the yield components that had the greatest effect on seed yield were hundred seed weight and pods plant⁻¹. Inoculation significantly (p< 0.05) affected 100 seed weight (2004-05). Plants inoculated with strain H 20 had the highest 100 seed weight at 25.2 g with cv. Scylla producing larger seeds than T-49. The belief that local environmental conditions play a major role on field survival of bacteria, led to the use of PCR methods to identify field nodulating organisms. Amplification of genomic DNA from parent isolates using primers fC and rD generated a single band for each isolate. Isolates were identified to the species level as either Rhizobium or Agrobacterium, using the highly conserved internally transcribed spacer (ITS) region and are known to nodulate common bean. The DNA extracted from the isolates recovered from nodules of field grown beans gave multiple bands with primers fC and rD. Five distinct banding patterns were observed. All of these were different from those of parent isolates. Sequencing of the 16S rRNA demonstrated that nodules of field grown beans in Canterbury were inhabited by Pseudomonads either alone or in association with other root nodulating organisms. The inability to identify the inoculant strains in nodules of field grown beans does not rule out their infection and nodulating function in the cultivars used. The results suggest the possibility of both Rhizobium and Pseudomonads cohabiting in the nodules of field grown beans. The aggressive nature of Pseudomonads on artificial media, possibly out competing the inoculant rhizobia is proposed, leading to the inability to identify the inoculant strain from the nodules of the field grown beans by PCR methods. The need to identify the nodule forming or nodule inhabiting bacteria in the nodules is necessary to classify the importance of these organisms and their economic benefit to agricultural production. This study also underlines the importance of using PCR methods to gain valuable insights into the ecological behaviour of Rhizobium inoculants and nodule inhabiting organisms.

The latter part of the reproductive growth phase in chickpea (<i>Cicer arietinum</i> L.) often coincides with declining temperature and wet conditions in western Canada, in sharp contrast to many other growing environments. This exacerbates the indeterminate nature of the crop, leading to excessive canopy development, and subsequently resulting in delayed maturity. The objectives of this study were to: i) determine the genetic relationships of short internode, double podding and early flowering traits with earliness of crop maturity; ii) determine the genetic control of major earliness traits in chickpea; iii) assess the patterns of post-flowering dry matter accumulation and partitioning to reproductive parts as related to earliness. <p>The results showed that double podding significantly reduced the number of days taken to maturity, under the conditions where this trait was sufficiently expressed. The best double podding genotypes, i.e. those with 1535% of the podded nodes bearing double pods, were about one week earlier than their single podding counterparts and standard checks. A physiological study revealed that the double podding parental genotype 272-2 partitioned a relatively greater proportion (about 58%) of the total dry matter to pods compared to 4254% in the single podding genotypes. Double podding increased the total number of pods set, and thus the increased demand for assimilates may have precluded further production of stems and leaves, resulting in an earlier transition of reproductive growth to physiological maturity. Days to flowering was positively associated with days to maturity, and partial path analysis revealed that days to flowering contributed to days to maturity indirectly via days to first pod maturity. Days to flowering explained 32% of the variation in days to first pod maturity. However, the short internode trait had an undesirable effect, in that all the short internode segregants were too late to mature. <p>Genetic studies revealed that days to flowering was determined by two major genes plus polygenes in chickpea in the short-season temperate environment of western Canada. The two major genes control over 65% of the phenotypic variation. Also, the additive component of genetic variance was significant for days to first podding, days to first pod maturity, reproductive period, and days to maturity; which is desirable for development of superior inbred cultivars of chickpea. These key phenological traits are interrelated but could be manipulated separately in the breeding process. Additional gain in earliness of crop maturity may be achieved through combined selection for these traits.

The latter part of the reproductive growth phase in chickpea (<i>Cicer arietinum</i> L.) often coincides with declining temperature and wet conditions in western Canada, in sharp contrast to many other growing environments. This exacerbates the indeterminate nature of the crop, leading to excessive canopy development, and subsequently resulting in delayed maturity. The objectives of this study were to: i) determine the genetic relationships of short internode, double podding and early flowering traits with earliness of crop maturity; ii) determine the genetic control of major earliness traits in chickpea; iii) assess the patterns of post-flowering dry matter accumulation and partitioning to reproductive parts as related to earliness. <p>The results showed that double podding significantly reduced the number of days taken to maturity, under the conditions where this trait was sufficiently expressed. The best double podding genotypes, i.e. those with 1535% of the podded nodes bearing double pods, were about one week earlier than their single podding counterparts and standard checks. A physiological study revealed that the double podding parental genotype 272-2 partitioned a relatively greater proportion (about 58%) of the total dry matter to pods compared to 4254% in the single podding genotypes. Double podding increased the total number of pods set, and thus the increased demand for assimilates may have precluded further production of stems and leaves, resulting in an earlier transition of reproductive growth to physiological maturity. Days to flowering was positively associated with days to maturity, and partial path analysis revealed that days to flowering contributed to days to maturity indirectly via days to first pod maturity. Days to flowering explained 32% of the variation in days to first pod maturity. However, the short internode trait had an undesirable effect, in that all the short internode segregants were too late to mature. <p>Genetic studies revealed that days to flowering was determined by two major genes plus polygenes in chickpea in the short-season temperate environment of western Canada. The two major genes control over 65% of the phenotypic variation. Also, the additive component of genetic variance was significant for days to first podding, days to first pod maturity, reproductive period, and days to maturity; which is desirable for development of superior inbred cultivars of chickpea. These key phenological traits are interrelated but could be manipulated separately in the breeding process. Additional gain in earliness of crop maturity may be achieved through combined selection for these traits.