<p>У раду су приказани резултати огледа са једанаест сорти пшенице (Triticum aestivum L.) и једном сортом тритикалеа (Triticosecale W.) на локалитету Кумане у Банату, у стресним условима халоморфног земљишта типа солоњец. Током три вегетационе сезоне је испитана генотипска варијабилност, праћењем фенотипске варијације и интеракције генотип/спољна средина за принос и компоненте приноса (висина биљке, дужина класа, маса класа, маса зрна по класу и број зрна по класу). Оглед је постављен на контролној варијанти (солоњец без поправке) и третманима са мерама поправке, уз примену фосфогипса у количини од 25 t/ha и 50 t/ha. За анализу интеракције генотипа и спољне средине је примењен Модел главних ефеката и вишеструке интеракције-AMMI (Аdditive Мain Еffects and Мultiplicative Interaction). Међузависност испитиваних особина је утврђена анализом једноструких корелација. У циљу дефинисања реакције генотипова на стресне услове солоњеца, испитанa је активност ензимских и неензимских компоненти антиоксидативног система, као и липидне пероксидације.<br />Испољена је статистичка значајност главних ефеката генотипа, агроекосредина и њихове интеракције на варијабилност свих испитиваних својстава. Уочени су генотипови мале интеракције генотип/спољна средина за поједине особине, што би могло да се окарактерише као стабилна реакција тих генотипова у променљивим условима средине, у односу на мелиоративни третман и вегетациону сезону. Корелационом анализом су<br />установљене значајне и високозначајне вредности коефицијената корелације између већине испитиваних својстава. Разлике у активности ензима и неензимских компоненти антиоксидативног система заштите указују да су генотипови различито реаговали на стресне услове солоњеца.<br />Добијени резултати могу да помогну процес стварања генотипова пшенице, који ће да се гаје на земљиштима са вишим концентрацијама натријума и неповољним физичким особинама, са добром стабилношћу.</p> / <p>U radu su prikazani rezultati ogleda sa jedanaest sorti pšenice (Triticum aestivum L.) i jednom sortom tritikalea (Triticosecale W.) na lokalitetu Kumane u Banatu, u stresnim uslovima halomorfnog zemljišta tipa solonjec. Tokom tri vegetacione sezone je ispitana genotipska varijabilnost, praćenjem fenotipske varijacije i interakcije genotip/spoljna sredina za prinos i komponente prinosa (visina biljke, dužina klasa, masa klasa, masa zrna po klasu i broj zrna po klasu). Ogled je postavljen na kontrolnoj varijanti (solonjec bez popravke) i tretmanima sa merama popravke, uz primenu fosfogipsa u količini od 25 t/ha i 50 t/ha. Za analizu interakcije genotipa i spoljne sredine je primenjen Model glavnih efekata i višestruke interakcije-AMMI (Additive Main Effects and Multiplicative Interaction). Međuzavisnost ispitivanih osobina je utvrđena analizom jednostrukih korelacija. U cilju definisanja reakcije genotipova na stresne uslove solonjeca, ispitana je aktivnost enzimskih i neenzimskih komponenti antioksidativnog sistema, kao i lipidne peroksidacije.<br />Ispoljena je statistička značajnost glavnih efekata genotipa, agroekosredina i njihove interakcije na varijabilnost svih ispitivanih svojstava. Uočeni su genotipovi male interakcije genotip/spoljna sredina za pojedine osobine, što bi moglo da se okarakteriše kao stabilna reakcija tih genotipova u promenljivim uslovima sredine, u odnosu na meliorativni tretman i vegetacionu sezonu. Korelacionom analizom su<br />ustanovljene značajne i visokoznačajne vrednosti koeficijenata korelacije između većine ispitivanih svojstava. Razlike u aktivnosti enzima i neenzimskih komponenti antioksidativnog sistema zaštite ukazuju da su genotipovi različito reagovali na stresne uslove solonjeca.<br />Dobijeni rezultati mogu da pomognu proces stvaranja genotipova pšenice, koji će da se gaje na zemljištima sa višim koncentracijama natrijuma i nepovoljnim fizičkim osobinama, sa dobrom stabilnošću.</p> / <p>This paper presents the results of an experiment with eleven varieties of wheat (Triticum aestivum L.) and one triticale variety (Triticosecale W.). The experiment was conducted in stress conditions of the site Kumane in Banat, on solonetz soil. Genotypic variability has been examined, during three growing seasons, through phenotypic variation and genotype/environment interaction for yield and yield components (plant height, spike length, spike weight, seed weight per spike and number of grains per spike). The experiment was set up in the control treatment (solonetz soil without melioration) and the improvement measures with application of phosphogypsum in amount of 25 t/ha and 50 t/ha. The genotype/environment ineraction was analyzed using AMMI model (Additive Main Effect and Multiplicative Interaction). The interrelationship of the studied traits was determined by the single correlation coefficients. In order to define the genotype response to stress of solonetz, the activity of enzimatic and non-enzimatic antioxidant system and lipid peroxidation were examined.<br />The statistical significance of the main effects of genotypes, environments and their interaction on variation of all the traits was observed. The observed genotypes with low genotype/environment interaction for certain traits, which could be characterized as a stable reaction of these genotypes in variable environmental conditions, in relation to the ameliorated measures and growin seson. For the different traits as the most stable ones, various genotypes were obtained. The genotypes in study reacted differently to different levels of melioration, in relation to each treatment<br />and growing season. Correlation analysis were established significant and highly significant values of correlation coefficients between the most of studied traits. Differences in the activity of enzymatic and non-enzymatic components of the antioxidant protection suggests that the genotypes responded differently to stress conditions of solonetz.<br />The results can help the process of creating wheat genotypes, which will be grown on soils with higher concentrations of sodium and unfavorable physical properties, which would have good stability.</p>

A field experiment was conducted to examine the responses in growth, total dry matter (TDM), seed yield and nitrogen (N) accumulation of Kabuli chickpea cv. Principe and narrow-leafed lupin cv. Fest to different irrigation levels and N fertilizer on a Templeton silt loam soil at Lincoln University, Canterbury, New Zealand in 2007/08. The irrigation and fertilizer treatments were double full irrigation, full irrigation, half irrigation and nil irrigation and a control, full irrigation plus 150 kg N ha⁻¹. There was a 51 % increase in the weighed mean absolute growth rate (WMAGR) by full irrigation over no irrigation. The maximum growth rates (MGR) followed a similar response. The growth rates were not significantly decreased by double irrigation. Further, N fertilizer did not significantly improve crop growth rates. With full irrigation MGRs were 27.6 and 34.1 g m⁻² day⁻¹ for Kabuli chickpea and narrow-leafed lupin, respectively. Seed yields of fully-irrigated crops were trebled over the nil irrigation treatment. With full irrigation, seed yield of chickpea was 326 and that of lupin was 581 g m⁻². Seed yield of the two legumes was reduced by 45 % with double irrigation compared with full irrigation. Nitrogen fertilizer did not increase seed yields in either legume. Increased seed yield with full irrigation was related to increased DM, and crop growth rates, seeds pod⁻¹ and seeds m⁻². Crop harvest index (CHI) was significantly (P < 0.05) increased by irrigation and was related to seed yield only in narrow-leafed lupin. With full irrigation, the crops intercepted more than 95 % of incoming incident radiation at leaf area indices (LAIs), 2.9 and 3 or greater in Kabuli chickpea and narrow-leafed lupin, respectively. In contrast, without irrigation the two legumes achieved a maximum fraction of radiation intercepted of less than 90 %. With full irrigation, total intercepted photosynthetically active radiation (PAR) was increased by 28 % and 33 % over no irrigation for Kabuli chickpea and narrow-leafed lupin, respectively. Fully-irrigated Kabuli chickpea intercepted a total amount of PAR of 807 MJ m⁻² and fully-irrigated narrow-leafed lupin intercepted 1,042 MJ m⁻². Accumulated DM was strongly related to accumulated intercepted PAR (R² ≥ 0.96**). The final RUE was significantly (P < 0.001) increased by irrigation. With full irrigation the final RUE of Kabuli chickpea was 1.49 g DM MJ⁻¹ PAR and that of narrow-leafed lupin was 2.17 g DM MJ⁻¹ PAR. Total N accumulation of Kabuli chickpea was not significantly affected by irrigation level. Kabuli chickpea total N was increased by 90 % by N fertilizer compared to fully-irrigated Kabuli chickpea which produced 17.7 g N m⁻². In contrast, total N accumulated in narrow-leafed lupin was not increased by N fertilizer but was decreased by 75 % with no irrigation and by 25 % with double irrigation (water logging) compared to full irrigation with a total N of 45.9 g m⁻². Total N was highly significantly related to TDM (R² = 0.78** for Kabuli chickpea and R² = 0.99** for narrow-leafed lupin). Nitrogen accumulation efficiency (NAE) of narrow-leafed lupin was not affected by irrigation or by N fertilizer. However, the NAE of Kabuli chickpea ranged from 0.013 (full irrigation) to 0.020 (no irrigation) and 0.017 g N g⁻¹ DM (full irrigation with N fertilizer). The N harvest index (NHI) was not affected by irrigation, N fertilizer or legume species. The NHI of Kabuli chickpea was 0.50 and that of narrow-leafed lupin was 0.51. The NHI was significantly (r ≥ 0.95 **) related to CHI.

This thesis is presented in the form of a series of papers some of which have already been published. It is prefaced by a review of research on the agronomy and physiology of wheat yield in New Zealand, and concluded with a general discussion, Other relevant papers in which the author was a contributor may be found in the Appendix. / Between 1972 and 1976 a series of field experiments were conducted to investigate the factors limiting grain yield in wheat (Triticum aestivum L). Spike population restricted yield when it was below about 500 spikes/m² but once it exceeded 700/m² grain yield declined due to a reduction in the number of grains per spikelet. Irrigation, high sowing rate, and nitrogen fertiliser generally increased spike number but the effects on the number of grains/spikelet were variable, apparently depending on processes related to leaf area index. The semi-dwarf Karamu outyielded New Zealand wheats when spring-sown because it produced more spikelets/spike and more grains/ spikelet than the other cultivars. The superior grain set of Karamu was because more of the distal florets within each spikelet produced grain than in the other cultivars. The results are discussed in relation to cultural practices and plant breeding.

Made available in DSpace on 2016-12-08T16:44:38Z (GMT). No. of bitstreams: 1 PGPV08MA069.pdf: 749700 bytes, checksum: 8827df9f189a59df731fb6cc3e561047 (MD5) Previous issue date: 2008-03-06 / The white oat (Avena sativa L.) is a winter cereal adapted different regions, used in the production of grains, green grass, hay, silage and mutch soil coverage in the winter. The leaf rust and helminthosporium are considered frequent diseases in oats. The damages are due to the reduction of the plant green area photosynthesis. This report aimed to obtain equations of damage function to multiple pathosystem involving leaf rust and helminthosporiosis in two white oat cultivars and correlate the disease intensity with the yield components. The experiments were performed in the Center of Agroveterinarian Sciences, Santa Catarina State University, Lages, SC experimental area, in the 2006 and 2007 agricultural harvest. The leaf diseases degree was generated through the use of increasing doses and number of applications (one, two and four) of pyraclostrobina + epoxiconazole (33.25 +12.5, 49.87 +18.75, 66.5 +25 g ai ha-1) fungicide in UPFA 20 Teixeirinha and UPFA 22 Temprana cultivars. The experimental units consisted of five lines of sowing, spaced at 0.20 m and five meters in length. Were analyzed the following variables: leaf incidence and severity, grain yield, a thousand grain mass and hectoliter weight. The disease evaluations were performed every 10 days pulling up randomly 10 plants per plot. Generally the helminthosporiosis was the prevalent disease in both agricultural harvest and oat cultivars until the flowering beginning. The leaf rust had its intensity increased in subsequent stages. In the first part of this study was attempted to determine the equations of damage function by the regression analysis between disease intensity and grain yield for each plant development stage. Significant equations were obtained for the UPFA 20 and UPFA 22 cultivars in both agricultural harvests, where through them was possible to calculate the Economic Damage Threshold (EDT) by phonological stage of culture. In its second part, the leaf incidence and severity values were submitted to the Area Under the Disease Progress Curve (AUDPC), which were correlated with the grain yield, thousand grain mass and hectoliter weight. There were negative and significant correlations from the AUDPC with grain yield, thousand grain mass and hectoliter weight in both growing season. From these values it was achieved that as higher is the leaf diseases intensity highest are the AUDPC values, resulting in the decrease of productive variables values. With values of grain yield, thousand grain mass and hectoliter weight the third work purpose quantify the economic damage treschold and control percentage of these two diseases according to the number and dose of fungicide application. The damage to the grain yield, thousand grains mass and hectoliter weight were higher in the 2007 harvest for both cultivars. The leaf diseases control percentage was higher in both cultivars in the 2007 harvest, reaching based on the leaf severity 86.74 % and 85.90 % respectively for UPFA 20 and UPFA 22 / A aveia branca (Avena sativa L.) é um cereal de estação fria adaptado a diferentes regiões, usada na produção de grãos, forragem verde, feno, silagem, e cobertura verde/morta de solo no inverno. A ferrugem da folha e a helmintosporiose são consideradas doenças freqüentes em aveia. Os danos causados são atribuídos à redução da área foliar fotossintetizante ativa da planta. O objetivo deste trabalho foi obter equações da função de dano para patossistema múltiplo envolvendo ferrugem da folha e helmintosporiose em duas cultivares de aveia branca e correlacionar a intensidade das doenças com componentes do rendimento. Os experimentos foram conduzidos na área experimental do Centro de Ciências Agroveterinárias, Lages, SC, nas safras agrícolas de 2006 e 2007. O gradiente das doenças foliares foi gerado pelo uso de doses crescentes e número de aplicações (uma, duas e quatro) do fungicida piraclostrobina + epoxiconazole (33,25+12,5, 49,87+18,75, 66,5+25 g de i.a. ha- 1) nas cultivares UPFA 20 Teixeirinha e UPFA 22 Temprana. As unidades experimentais constaram de cinco linhas de semeadura, espaçadas em 0,20 m, com cinco metros de comprimento. Analisaram-se as seguintes variáveis: incidência e severidade foliar, rendimento de grãos, massa de mil grãos e peso do hectolitro. As avaliações de doença foram realizadas a cada 10 dias retirando-se 10 plantas aleatoriamente das parcelas. Em geral a helmintosporiose foi a doença predominante nas duas safras agrícolas e duas cultivares de aveia até o início do florescimento. A ferrugem da folha teve sua intensidade aumentada nos estádios subseqüentes. Na primeira parte deste trabalho procurou-se determinar as equações da função de dano pela análise de regressão entre intensidade de doença e rendimento de grãos para cada estádio de desenvolvimento das plantas. Foram obtidas equações significativas para as cultivares UPFA 20 e UPFA 22 nas duas safras agrícolas, onde por meio destas pode-se calcular o Limiar de Dano Econômico por estádio fenológico da cultura. Em sua segunda parte, os valores de incidência e severidade foliar foram utilizados para calcular à Área Abaixo da Curva de Progresso da Doença (AACPD), os quais foram correlacionados com o rendimento de grãos, massa de mil grãos e peso do hectolitro. Houve correlações negativas e significativas da AACPD com rendimento de grãos, massa de mil grãos e peso do hectolitro nas duas safras agrícolas. Destes concluiu-se que quanto maior a intensidade das doenças foliares maior são os valores da AACPD, resultando na diminuição dos valores das variáveis produtivas. De posse dos valores de rendimento de grãos, massa de mil grãos e peso do hectolitro a terceira parte deste trabalho teve como objetivo quantificar o percentual de dano, e controle destas duas doenças em função do número e dose de aplicação do fungicida. Os danos ao rendimento de grãos, massa de mil grãos e peso do hectolitro foram maiores na safra de 2007 para as duas cultivares. A percentagem de controle das doenças foliares foi maior nas duas cultivares na safra de 2007, atingindo com base na severidade foliar 86,74 % e 85,90 %, respectivamente para UPFA 20 e UPFA 22

Made available in DSpace on 2014-08-20T13:44:31Z (GMT). No. of bitstreams: 1 tese_jadiyi_concepcion_torales_salinas.pdf: 562734 bytes, checksum: 6ac3d6b04cd3273b14f7b555a86a9970 (MD5) Previous issue date: 2013-04-03 / It was conducted three research projects aimed at better understanding of the effect of aluminum silicate on yield and quality of soybean seeds as a source of silicon in the mineral nutrition and plant protection. In the first study was evaluated the effect of five doses of aluminum silicate applied via foliar as a source of silicon in the mineral nutrition acting on the yield and quality of soybean seeds produced in Arroio Grande, Rio Grande do Sul, Brazil. In the second study was evaluated the effect of different doses of aluminum silicate, silicon source, applied to the soil and leaves in yield components of soybean seeds produced in San Lorenzo, Paraguay. And the third experiment was evaluated the effect of different doses and aluminum silicate, applied via foliar and soil as a source of silicon in the mineral nutrition and plant protection, acting as seeds produced in San Lorenzo, Paraguay. The results obtained in the three studies showed that aluminum silicate applied foliar or soil had no effect on yield components. Seeds from plants that received foliar or soil application of aluminum silicate. There are changes in their physiological quality. / Foram conduzidos três trabalhos de pesquisa que visam melhor entender o efeito da aplicação de silicato de alumínio no rendimento e qualidade de sementes de soja como fonte de silício na nutrição mineral e proteção de plantas. No primeiro trabalho avaliou-se o efeito de cinco doses de silicato de alumínio aplicadas via foliar, como fonte de silício na nutrição mineral atuando no rendimento e na qualidade das sementes de soja produzidas em Arroio Grande, Rio Grande do Sul, Brasil. No segundo trabalho avaliou-se o efeito de diferentes doses de silicato de alumínio, como fonte de silício, aplicada no solo e via foliar, nos componentes de rendimento de sementes de soja produzidas em São Lorenzo, Paraguai. E no terceiro experimento avaliou-se e efeito de doses diferentes de silicato de alumínio, aplicadas via foliar e no solo, como fonte de silício na nutrição mineral e proteção vegetal, atuando na qualidade de sementes de soja produzidas em São Lorenzo, Paraguai. Os resultados obtidos nos três trabalhos permitiram concluir que o silicato de alumínio aplicado via foliar ou no solo não apresenta efeitos sobre os componentes do rendimento. Sementes provenientes de plantas que receberam aplicação foliar ou no solo de silicato de alumino, não sofrem alterações na sua qualidade fisiológica.

La lentille (Lens culinaris Med.) est une composante importante des régimes alimentaires de nombreuses populations à travers le monde mais sa consommation en Europe est relativement faible. L’Europe produit seulement 26% de sa consommation de lentille et ce déficit est en partie causé par d’importants verrous agronomiques comme la verse, les bruches et la compétition des adventices qui réduisent ses rendements, notamment en agriculture biologique. Les associations de cultures, définies comme la culture simultanée d’au moins deux espèces différentes sur une même surface pendant une durée significative, sont considérées comme une option pour lever ces verrous agronomiques et ainsi développer la production de lentille en agriculture biologique. Les objectifs de cette thèse étaient de (1) évaluer le potentiel des associations de lentille et de blé de printemps pour produire de la lentille en conditions d’agriculture biologique et (2) comprendre les principaux mécanismes sous-jacents à la performance des associations. Des essais agronomiques ont été mis en place en 2015 et 2016 en conditions d’agriculture biologique. Quatre variétés de lentille et de blé de printemps ont été conduites en culture pures et en plusieurs associations de type substitutif et additif. Nos résultats montrent que le rendement moyen des associations avant récolte mécanique était plus élevé que le rendement moyen des cultures pures. Néanmoins, le rendement de lentille en association était inférieur à celui de la lentille en culture pure en raison d’une compétition forte et précoce du blé pour les ressources qui a causé la diminution nombre de ramifications par plante de la lentille. Le prix de la lentille étant environ quatre fois plus élevé que celui du blé, la marge brute des associations avant récolte était inférieure à celle de la lentille en culture pure. Cependant, la verse de la lentille a été fortement réduite en association, entrainant une augmentation de l’efficacité de sa récolte mécanique. En conséquence les rendements de lentille issus de la récolte mécanique se sont avérés similaires en association et en culture pure. Enfin, après tri et nettoyage des graines, la marge brute des associations sur le rendement commercialisable était supérieure à celle des cultures pures. Nos résultats montrent que (1) les associations n’ont pas eu d’effet sur le taux de bruchage des lentilles, (2) l’association la plus performante est constituée de lentille à densité équivalente à la culture pure dans laquelle on ajoute 15-20% de blé, (3) la performance des associations est due à une utilisation complémentaire de l’azote rendue possible par la fixation symbiotique de l’azote par la lentille et (4) l’intensité des compétitions entre espèces dépendent de l’année, de la densité de blé et des génotypes. En conclusion, nos travaux indiquent que les associations de lentille et de blé de printemps peuvent permettre de développer la production de lentille en agriculture biologique mais qu’une meilleure compréhension des interactions de type génotype x environnement x conduite pourrait permettre de mettre au point des couverts encore plus performants. / Lentil (Lens culinaris Med.) is an important component of the human diet in the world, but in the meantime, Europe produces only 26% of the lentils it consumes. This is partly due to strong agronomic weaknesses that reduce yield such as lodging, bruchid beetles and weeds, especially in organic farming. Intercropping, the simultaneous growing of two or more species in the same field is tested here as an option to reduce these drawbacks and develop organic lentil production. The aims of this thesis were to (1) assess the potential of lentil-spring wheat intercrops to produce organic lentil, (2) understand the mechanisms that explain their performances, and (3) evaluate the profitability of such intercrops. A two-year field experiment was carried out in southwestern France in 2015 and 2016 under organic farming rules. Four lentil and two wheat cultivars were grown as sole crops and intercrops in multiple additive and substitutive designs. Our results showed that the total intercrop attainable grain yield was higher than the mean of sole crops. Yet, lentil yield in intercrop was lower than in sole crop as the result of a strong competition for resources from wheat in early lentil growth stages reducing the number of branches per plant of lentil. This led to lower gross margins of intercrops. However, lentil lodging was strongly reduced in intercrops thus its mechanical harvest efficiency increased. This led to similar mechanically harvested yields of lentil in intercrop and sole crop. Consequently, after mechanical harvest and grain cleaning, the marketable gross margin of intercrops was higher than that of sole crops. Our results suggest that (1) intercrop had no effect on bruchids, (2) the most effective intercrop is when lentil is at sole crop density and wheat at 15-20%, (3) intercrop performance is due to complementary use of N pools through legume N2 fixation and (4) the intensity of interspecific interactions depends on year, wheat density and genotypes. Our work indicates that lentil-spring wheat intercrop can develop organic lentil production but a better understanding of Genotype x Environment x Cropping system interactions may be useful to design optimized managements.

The association between individual plant performance and seed yield variability within and between field pea crops was investigated. In 1988/89 six F8 genotypes with morphologically distinct characteristics were selected from a yield evaluation trial. Analysis of the individual plant performance within these crops indicated an association between low seed yields and the location and dispersion of plant harvest index (PHI) and plant weight (PWT) distributions. The analyses also showed there was a strong linear relationship between the seed weight (SWT) and PWT of the individual plants within each crop, and that the smallest plants tended to have the lowest PHI values. A series of 20 simulations was used to formalize the relationships between SWT, PWT and PHI values within a crop into a principal axis model (PAM). The PAM was based on a principal axis which represented the linear relationship between SWT and PWT, and an ellipse which represented the scatter of data points around this line. When the principal axis passed through the origin, the PHI of a plant was independent of its PWT and the mean PHI was equal to the gradient of the axis. However, when the principal axis had a negative intercept then the PHI was dependent on PWT and a MPW was calculated. In 1989/90 four genotypes were sown at five plant populations, ranging from 9 to 400 plants m⁻². Significant seed and biological yield differences were detected among genotypes at 225 and 400 plants m⁻². The plasticity of yield components was highlighted, with significant genotype by environment interactions detected for each yield component. No relationship was found between results for yield components from spaced plants and those found at higher plant populations. The two highest yielding genotypes (CLU and SLU) showed either greater stability or higher genotypic means for PHI than genotypes CVN and SVU. Despite significant skewness and kurtosis in the SWT, PWT, and PHI distributions from the crops in this experiment, the assumptions of the PAM held. The lower seed yield and increased variability in PHI values for genotype CVN were explained by its higher MPW and the positioning of the ellipse closer to the PWT axis intercept than in other genotypes. For genotype SVU, the lower seed yield and mean PHI values were explained by a lower slope for the principal axis. Both low yielding genotypes were originally classified as having vigorous seedling growth and this characteristic may be detrimental to crop yields. A method for selection of field pea genotypes based on the PAM is proposed. This method enables the identification of weak competitors as single plants, which may have an advantage over vigorous plants when grown in a crop situation.

No description available.

Studies were conducted on three field trials of wheat cv. Kopara to investigate the lack of compensation by later determined components of yield because of early disease constraints. The investigation was based on the hypothesis that early disease reduces root development and thus causes the plants to be water constrained at later growth stages when soil water deficits usually occur. The reduced root development and soil water deficits may reduce the ability of the plant to compensate for reductions in early determined components. The hypothesis was tested by the application of irrigation to alleviate water stress. In a disease free crop, the possible phytotonic effects of the fungicides benomyl and triadimefon on wheat were investigated. These fungicides had no phytotonic effects on shoot, root growth, or yield under the prevailing conditions. The effect of disease on root development was analysed by root length measurements. Disease present in the crop at any stage of growth affected root development. Root development in the upper zones of the soil profile was reduced more by disease compared to those zones below 35 cm. A full disease epidemic reduced root development more than an early or late disease epidemic. The early and late disease epidemics had similar effects on root length. Alleviation of early disease constraints enabled greater development of roots to offset any earlier reductions. Soil water deficits increased root development in the lower zones of the nil disease plants. The presence of adequate soil water from irrigation reduced the requirement for further root growth in all treatments. In the 1981-1982 field trial a full disease epidemic reduced yield by 14% whereas an early disease epidemic reduced yield by 7%. The reduction in yield was attributed to a lower grain number. With irrigation the yield reduction in the full disease plants was 12% whereas in the early disease plants the reduction was only 2.4%. This indicated that plants affected by the early disease epidemic were water constrained. In this study, the results suggested that, for conditions prevailing in Canterbury, the supply of water at later growth stages increased grain weight in plants which were subject to early disease epidemics. This suggests that reduced root development caused by early disease and soil water deficits may prevent compensation by grain weight. Water use was similar in all disease treatments. After irrigation the irrigated plants of all treatments used more water. Disease affected water use in relation to yield production however, and was better expressed by water use efficiency. Water use efficiency was reduced in the full disease plants. A stepwise regression analysis suggested that water use efficiency was affected directly by disease at later growth stages, and indirectly via an effect on total green leaf area at early growth stages. This study partially proves the hypothesis that reductions in root development caused by an early disease epidemic may constrain the plants at later growth stages when water deficits usually occur. It was shown that the reduction in root development caused by disease could be counteracted by irrigation. In this respect, water served as a tool to study the effect of disease constraints on the yield of wheat. A knowledge of cereal crop physiology, root growth and function is used to explain and discuss the observations made in this research programme. The results are discussed in relation to the way in which disease affects yield through its effect on root development. The possible reasons for the continued effects of disease even after the control of disease at later growth stages are discussed. The economic use of fungicides and water in diseased crops are also outlined. Suggestions for future studies on disease-yield loss relationships are provided. The repetition of these experiments in different sites and climatic regions could provide information which may be incorporated in disease-yield loss simulation models. This could then be used to predict root development and water requirements of diseased plants, and provide a basis for economic use of fungicides and water, and for better disease management programmes.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The common bean (Phaseolus vulgaris L.) is an important calcium source for human diet, thus the evaluation of the calcium use efficiency in common bean a relevant tool for crop sustainability. The aims of this study were to evaluate the response in common bean cultivars with different calcium concentrations in nutrient solution on dry matter production, yield components and calcium, potassium and magnesium accumulations; to investigate the association between these characters; to evaluate the genetic variability of lines for calcium availability in the solution; and identify lines of common bean-efficient and responsive to calcium application by different indexes. For this, three experiments were conducted from March 2011 to July 2012 in greenhouse, in a completely randomized design, in splitplots. In the first two experiments were tested calcium concentrations in nutrient solution from 1.10 to 4.95 mmol L-1 as components of the main plot and the BRS Expedito, Carioca and Iraí cultivars on subplots in the first experiment, with the exclusion of the cultivar Iraí in the second experiment. The third experiment evaluated the efficiency and the response of the calcium use of 12 different common bean lines at low (1.10 mmol L-1) and high (3.85 mmol L-1) calcium concentrations in the nutrient solution. Higher values for dry matter and grain yield components were observed for 3.30 mmol L-1 and 4.95 mmol L-1 calcium concentrations in the solution. The common bean cultivars acumulate greater quantity of calcium in the leaves, followed by stems, pods and grains. Highest accumulation of calcium in the leaves was obtained at a 4.95 mmol L-1 calcium concentration in the nutrient solution, and the calcium concentration in the leaves was 21 times higher than the value obtained in the bean grains. The increase of calcium concentration in the nutrient solution up to the concentration of 4.95 mmol L-1 does not change the absorption and the accumulation of potassium and magnesium in leaves and grains. Indirect selection by greater dry matter and higher values of the variables that form the grain yield in common bean will be efficient to increase the accumulation of calcium in grains. The lines L 15, L 234, L 246 and L 77 respond to the increase on calcium supply in the solution, because more calcium accumulates in grain in the cultivation with high calcium concentration. The lines L 246 and L 15 are calcium use efficient in the plant, in the acquisition and grain production, and are not responsive to calcium application. The line L 77 is calcium use efficient in the plant and in the grain production and is responsive to the calcium application in the nutrient solution. / O feijão (Phaseolus vulgaris L.) é uma importante fonte de cálcio para a alimentação humana, sendo a avaliação da eficiência no uso de cálcio em feijão uma ferramenta relevante para a sustentabilidade da cultura. Foram objetivos desse trabalho avaliar a resposta de cultivares de feijão a diferentes concentrações de cálcio em solução nutritiva na produção de massa seca, nos componentes da produtividade de grãos e no acúmulo de cálcio, potássio e magnésio; investigar a associação entre esses caracteres; avaliar a variabilidade genética de linhagens de feijão quanto a disponibilidade de cálcio na solução e identificar linhagens eficientes no uso de cálcio e responsivas a aplicação deste mineral por diferentes índices. Para isso foram realizados três experimentos no período de março de 2011 a julho de 2012, em casa-devegetação, em delineamento inteiramente casualizado, com parcelas subdivididas. Nos dois primeiros experimentos foram testadas concentrações de cálcio na solução nutritiva de 1,10 a 4,95 mmol L-1 como componentes da parcela principal e as cultivares BRS Expedito, Carioca e Iraí nas subparcelas no primeiro experimento, com a exclusão da cultivar Iraí para o segundo experimento. No terceiro experimento foram avaliadas a eficiência no uso e a resposta de 12 linhagens de feijão em baixa (1,10 mmol L-1) e em alta (3,85 mmol L-1) concentração de cálcio na solução nutritiva. Maiores valores para massa seca e para os componentes da produtividade de grãos foram observados para as concentrações de 3,30 mmol L-1 e de 4,95 mmol L-1. As cultivares de feijão acumulam maior quantidade de cálcio nas folhas, seguido pelos caules, vagens e grãos. Maior acúmulo de cálcio nas folhas foi obtido na concentração de 4,95 mmol L-1 de cálcio na solução nutritiva, quando a concentração de cálcio nas folhas é 21 vezes superior ao valor obtido nos grãos de feijão. O aumento da concentração de cálcio na solução nutritiva até a concentração de 4,95 mmol L-1 não altera a absorção e o acúmulo de potássio e de magnésio nas folhas e nos grãos de feijão. A seleção indireta pela maior massa seca de parte aérea e maiores valores das variáveis que formam a produtividade de grãos em feijão será eficiente para aumentar o acúmulo de cálcio nos grãos de feijão. As linhagens L 15, L 234, L 246 e L 77 respondem ao aumento do suprimento de cálcio na solução, pois acumulam mais cálcio nos grãos em cultivo com alta concentração deste mineral. As linhagens L 246 e L 15 são eficientes no uso de cálcio na planta, na aquisição de cálcio e na produção de grãos, e não são responsivas à aplicação de cálcio. A linhagem L 77 é eficiente no uso de cálcio na planta e na produção de grãos e é responsiva à aplicação de cálcio na solução nutritiva.