Tesis sobre el tema "Cowpea – Growth"

Genotype X cropping system interactions may complicate the plant breeders' task of increasing crop yields, since selection and improvement in one cropping system may not result in improved performance in a different cropping system. Field experiments were conducted in 1990 and 1991 to examine the effects of cowpea (Vigna unguiculata (L.) Walp.) genotypes and cropping systems on cowpea yield, yield components, biomass, and leaf area. When cowpea was grown in sole crop and in intercrop with pearl millet (Pennisetum americanum (L.) Leeke), a significant genotype X cropping system interaction for seed yield occurred in both years. In sole crop, 'California Blackeye 46' (CB46) yielded more than 'Tohono O'odham' (TOC). By contrast, in intercrop, there was no difference in yield between genotypes in 1990, but TOC outyielded CB46 in 1991. More vegetative biomass and leaf area was produced by TOC than CB46 and more was produced in sole crop than intercrop. In intercrop, TOC produced more leaf area in the furrow and higher in the intercrop canopy than CB46. TOC had a more negative effect on millet than CB46. In intercrops differing in row-spatial arrangement (within- and between-row intercrops), TOC outyielded CB46 in both the within- and between-row intercrops, and more yield was produced in the between-row than within-row intercrop. To identify plant traits associated with cowpea seed yield under intercropping, three F₂ cowpea populations were grown in intercrop with millet. All three yield components (pod number, seeds per pod, and mean seed weight) were significantly correlated with cowpea seed yield. The number of pods accounted for most of the variation in seed yield. There was a negative association between seeds per pod and mean seed weight. Plant length, number of nodes, and number of branches were also correlated with seed yield, as were the number of pods produced on basal and distal branches and from the longest (> 10 cm) internode category. Plant traits associated with yield in intercrop may differ from those associated with yield in sole crop. Hence, selection criteria for indirectly selecting yield will differ between cropping systems.

Abstract A field experiment involving two plant densities (83,333 and 166,666 plants per hectare), two cropping systems (monoculture and mixed culture) and five cowpea (Vigna unguiculata L. Walp.) genotypes (3 farmer-selected varieties: Bensogla, Sanzie and Omondaw, and 2 breeder-improved cultivars: ITH98-46 and TVuI509) was conducted for two years in 2005 and 2006 at Nietvoorbij (33°54S, 18°14E), Stellenbosch, South Africa, to evaluate the effect of these treatments on the growth and symbiotic performance of cowpea. The results showed that, of the five cowpea genotypes, plant growth and N2 fixation were significantly greater in the three farmer-selected varieties (Sanzie, Bensogla and Omondaw) relative to the two improved cultivars (ITH98-46 and TVuI509). Furthermore, plant growth and symbiotic performance (measured as tissue N concentration, plant N content, 15N natural abundance and N-fixed) were significantly (P:50.05) decreased by both high plant density and mixed culture (intercropping). However, the %Ndfa values were significantly (P:S0.05) increased by both high plant density and mixed culture compared to low plant density or monoculture (or monocropping). Whether under low or high plant density, the cv. Sanzie was found to accumulate significantly greater total N per plant in both 2005 and 2006, followed by the other two farmer varieties relative to the improved cultivars. Similarly, the actual amount ofN-fixed was much greater in cv. Sanzie, followed by the other farmer varieties, under both low and high plant density. The data also showed better growth and greater symbiotic N yield in cowpea plants cultivated in monoculture (or low plant density) relative to those in mixed culture (or high plant density). Our data suggest that optimising legume density in cropping systems could potentially increase N2 fixation in cowpea, and significantly contribute to the N economy of agricultural soils in Africa.

Abstract In 2005 and 2006, 30 and 15 cowpea genotypes were respectively evaluated for plant growth and symbiotic performance at Manga in Northern Ghana, in order to identify Nz-fixing potential of these cowpea genotypes as source of N for cropping systems. The results showed differences in biomass production by the 30 or 15 cowpea genotypes. In 2005, cultivars Fahari, Mchanganyiko, IT97K-499-39, IT93K-2045-29 and IT84S-2246 produced the most shoot biomass, while Apagbaala, Brown Eye, ITH98-46, Vita 7 and Iron Grey produced the least. Of the 15 genotypes tested in 2006, cv. TVu1l424 produced the largest amount of biomass, and ITH98-46, the least. Isotopic analysis of 15N in plant parts also revealed significant differences in 1)15N of the cowpea genotypes studied. As a result, the percent N derived from fixation (% Ndfa) also differed among the cowpea genotypes tested in 2005, with only 5 out of the 30 cultivars obtaining over 50% of their N from symbiotic fixation. Whether expressed as mg Nplant' or kg N.ha-I , the levels of Nz fixation by the cowpea genotypes varied considerably during 2005 and 2006, with values ofN contribution ranging from 14.1 kg N.ha-1 by cv. TVul509 to 157.0 kg N.ha-1by IT84S-2246 in 2005. The amounts ofN-fixed in 2006 ranged from 16.7 kg N.ha-1 by cv. ITH98-46 to 171.2 kg N.ha-1 by TVu11424, clearly indicating genotypic differences in symbiotic N yield. Re-evaluating 15 out of the 30 cowpea genotypes for Nz fixation in 2006, revealed higher % Ndfa values (>50%) in all (15 cowpea genotypes) relative to those tested in 2005, indicating greater dependence on Nz fixation for their N nutrition even though, the actual amounts of fixed-N were lower in 2006. This was due, in part, to reduced plant biomass as a result of very late sampling in 2006, close to physiological maturity (72 DAP in 2006 vs. 46 DAP in 2005) when considerable leaf matter was lost. The amount ofNfixed in 2006 can therefore be considered as being under-estimated.

Thesis (M. S.)--Michigan State University. Dept. of Food Science and Human Nutrition, 2006.
Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references (p. 67-70). Also issued in print.

Thesis (DTech (Faculty of Applied Sciences)--Cape Peninsula University of Technology, 2009
A 3-factorial experiment involving two cowpea densities (83,000 and 167,000 plants.ha-1), two cropping systems (i.e. monoculture and mixed culture) and five cowpea genotypes (i.e. three farmer-selected cultivars, Bensogla, Sanzie and Omondaw and two improved varieties, ITH98-46 and TVu1509) was conducted in the field for two consecutive years in 2005 and 2006. The aim was to assess the effect of plant density, cropping system and cowpea genotypes on: (i) chlorophyll and gas-exchange, (ii) rhizosphere mineral concentration and tissue uptake of nutrients, (iii) acid and alkaline phosphatase activities in the rhizosphere, (iv) plant growth and symbiotic performance, and (v) concentration of flavonoids and anthocyanins in seed extracts and plant organs and their effect on pest infestation and diseases. The results showed that high plant density (167,000 plants.ha-1) and mixed culture significantly decreased gas-exchange parameters, leaf chlorophyll content, 13C and %C in both cowpea and sorghum plants compared with low plant density (83,000 plants.ha-1) and monoculture. The data also showed significantly higher 13C and lower %C in ITH98-46 and TVu1509 compared with Bensogla, Omondaw and Sanzie genotypes with a significant correlation between 13C and water-use efficiency. At harvest, grain yield of cowpea and sorghum was significantly decreased by high plant density and mixed culture compared with low plant density and monoculture. Sanzie genotype was generally superior in grain yield (2,550 kg.ha-1) followed by cvs. Omondaw and Bensogla (2,250 and 2,150 kg.ha-1, respectively) compared with the improved cultivars. Sorghum plants in mixture with cv. TVu1509 or cv. ITH98-46 performed better (1,570 and 1,550 kg.ha-1, respectively) compared with those in mixture with other cultivars. The results also showed greater land equivalent ratio (LER = 1.42 to 1.52), suggesting that mixed culture produced greater total yields per unit land area compared with monoculture.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
A sensibilidade à salinidade varia com o estÃdio de desenvolvimento da cultura. O feijÃo-de-corda [Vigna unguiculata (L.) Walp.] constitui uma das principais culturas, em diversas regiÃes semi-Ãridas do mundo. Avaliou-se o efeito da irrigaÃÃo com Ãgua salina, aplicada em diferentes estÃdios de desenvolvimento de plantas de feijÃo-de-corda. O experimento foi conduzido no campo, e obedeceu ao delineamento em blocos ao acaso, com cinco tratamentos (T1, T2, T3, T4 e T5) e cinco repetiÃÃes. O feijÃo-de-corda foi cultivado no espaÃamento de 0,8 m entre linhas e 0,3 m entre plantas, com duas plantas por cova. Os tratamentos utilizados foram: T1 - plantas irrigadas com Ãgua do poÃo (CEa de 0,8 dS m-1) durante todo o ciclo; T2 - Ãgua salina com CEa de 5,0 dS m-1, com aplicaÃÃo iniciada apÃs a germinaÃÃo e permanecendo atà o final do ciclo; T3 - Ãgua salina com CEa de 5,0 dS m-1, da semeadura atà 22 dias apÃs o plantio (DAP), correspondendo Ãs fases de germinaÃÃo e crescimento inicial, e Ãgua do poÃo no restante do ciclo; T4 - Ãgua salina com CEa de 5,0 dS m-1, aplicada de 23 a 42 DAP (fase de intenso crescimento vegetativo atà a prÃ-floraÃÃo), e Ãgua do poÃo nas demais fases do ciclo; T5 - Ãgua do poÃo da semeadura atà 42 DAP e Ãgua salina (CEa de 5,0 dS m- 1) aplicada a partir dos 43 DAP (floraÃÃo e frutificaÃÃo). Foram avaliadas a cobertura vegetal do solo, crescimento vegetativo, fotossÃntese, transpiraÃÃo, condutÃncia estomÃtica, produtividade, partiÃÃo de matÃria seca, os teores, os totais extraÃdos e a distribuiÃÃo dos nutrientes na planta, a eficiÃncia nutricional, eficiÃncia no uso da Ãgua e o acÃmulo de sais no solo. A irrigaÃÃo com a combinaÃÃo de Ãgua do poÃo com Ãgua salina reduziu o acÃmulo de sais no solo, em relaÃÃo ao T2. O T2 reduziu as taxas de fotossÃntese e transpiraÃÃo, em relaÃÃo ao T1. O T3 provocou reduÃÃo das trocas gasosas somente na primeira mediÃÃo, enquanto, que similar aplicaÃÃo nos outros estÃdios (T4 e T5) nÃo provocou reduÃÃes significativas nas trocas gasosas das plantas. O T2 inibiu o crescimento vegetativo da planta, enquanto o T3 provocou retardo no desenvolvimento da planta. Os tratamentos T2 e T3 provocaram reduÃÃes significativas no nÃmero de vagens e na produÃÃo de sementes por planta, em relaÃÃo aos demais tratamentos. Por outro lado, os tratamentos T4 e T5 nÃo afetaram o crescimento e a produtividade da cultura, sendo que o T4 causou aceleraÃÃo no ciclo reprodutivo da cultura. Os minerais foram extraÃdos pelo feijÃo-de-corda na seguinte ordem decrescente: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, no entanto, o T2 reduziu a extraÃÃo da maioria dos elementos analisados, com exceÃÃo do Na e Cl. Os minerais Na, Cl, K, Ca, Fe e Mn permaneceram preferencialmente nas partes vegetativas enquanto N e P foram exportados em maiores proporÃÃes pelos frutos. O T3 reduziu a eficiÃncia de utilizaÃÃo da maioria dos nutrientes. O T2 reduziu a eficiÃncia agronÃmica de utilizaÃÃo de N, P e K, entretanto nÃo afetou a eficiÃncia de utilizaÃÃo dos nutrientes extraÃdos pelas plantas.
The sensitivity of crops to salinity often changes from one growth stage to another. Cowpea [Vigna unguiculata (L.) Walp.] is an important crop specie cultivated in different semi-arid regions of the world. The objective of this work was to evaluate the effect of the irrigation with saline water, applied at different growth development stages of cowpea. The experiment was set up in the field, during the dry season. A completely randomized block design, with five treatments (T1, T2, T3, T4 and T5) and five repetitions, was adopted. The distance between lines and plants were 0.8 m and 0.3 m, respectively, with two plants per hole. The treatments studied were: T1 - Groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; T2 - Saline water (ECw = 5.0 dS m-1) during the whole crop cycle, starting after germination; T3 - Saline water (ECw = 5.0 dS m-1) from sowing until the 22th day after sowing (germination and initial growth) and groundwater in remaining stages of the crop cycle; T4 - Saline water (ECw = 5.0 dS m-1) from the 23th to the 42nd day after germination (intense growth and pre-flowering), and groundwater irrigation for the remaining growth stages. T5 - Groundwater from sowing to the 42nd day after sowing and saline water (ECw = 5.0 dS m-1) during flowering and pod-filling stages. Soil coverage, gas exchange, vegetative growth and crop yield were measured. The mineral concentration and quantity of nutrient removed from the soil, as well as the nutrient use efficiency and salt accumulation in soil were also determined. The irrigation with combination of groundwater and saline water reduced the salt accumulation in soil, in relation to continuous use of saline water. The continuous application of water with ECw of 5.0 dS m-1 (T2) reduced the rates of photosynthesis and transpiration, in relation to the well water (T1). Plants of the treatment 3 showed reduction in gas exchanges only in the first measurement, while the saline water application in other growth stages (T 4 and T5) did not provoke significant reductions in leaf in the gas exchanges of the plants. It was found that the continuous use of saline water inhibits plant growth, while the irrigation with saline water during germination and initial growth causes retardation in plant development. For treatments 2 and 3, reduction in the number of pods and in seed production was verified. Irrigation with saline water from the 23rd to the 42nd day (T4) and from the 43rd to the 63rd (T5) day after sowing did not affect reproductive and vegetative growth, but the saline water application in the pre-flowering (T4) caused anticipation of reproductive cycle. Cowpea plants removed the minerals analyzed in the following decreasing sequence: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, but the continuous use of saline water (T2) reduced the total extracted for the most nutrients, except for Na e Cl. The minerals Na, Cl, K, Ca, Fe and Mn were distributed preferentially to vegetative plant parts, while the most of N and P were exported in the pods. The irrigation with saline water during germination and initial growth stage (T3) reduced the mineral use efficiency of most of analyzed nutrients. The continuous application of saline water (T2) reduced the agronomic efficiency of the fertilizer application (N, P and K), but it did not affect the nutrient use efficiency by the plants.

Abstract In this study, 30 cowpea genotypes were assessed for symbiotic N2 fixation in 2005, and 15 of them were reevaluated in 2006 using the 15N natural abundance technique. Shoot dry matter yield of cowpea genotypes increased significantly in cvs. Vuli-1, Glenda, IT93K-2045- 29, IT90K-59, Omondaw, Apagbaala, and IT84S-2246 in 2005 producing about 3.0 to 3.6-fold more biomass relative to cv. Vallenga. In 2006, seven out of the 15 cowpea genotypes tested (namely, IT97K-499-39, TVu11424, Botswana White, IT84S-2246, Sanzie, Brown Eye, and Glenda) also produced more dry matter than cv. CH14. Shoot δ15N values ranged from −0.58‰ to 1.49‰ in 2005, and −1.51‰ to 1.40‰ in 2006, and these resulted in %Ndfa values of 63.5–86.7% and 56.2–96.3%, respectively. The amount of N-fixed was 49–178 kg N ha−1 in 2005 and 62–198 kg N ha−1 in 2006. Furthermore, there was a direct relationship between the level of symbiotic N nutrition and plant growth, and between grain yield and amount of N-fixed in 2005 and 2006. As a result, genotypes that fixed the most N also produced the largest biomass and the greatest amount of grain yield. The observed relationship between N2 fixation and biomass confirmed our view that cowpea (and other grain legumes) can be concurrently selected for higher N2 fixation, superior plant growth, and greater grain yield. The high levels of N-fixed by many of the cowpea genotypes in this study suggest that they can contribute large amounts of N to cropping systems in African agriculture.

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior
Este trabalho teve por objetivo estudar os efeitos da aplicaÃÃo de Ãgua (CEa = 0,5 dS m-1) e ou soluÃÃo salina (CEa = 5,0 dS m-1), alternadamente, em diferentes fases de desenvolvimento do feijÃo de corda cv. Epace 10. Foram realizados dois experimentos, em condiÃÃes de ambiente protegido (telado), na Embrapa AgroindÃstria Tropical. Em ambos, as sementes foram colocadas em vasos dispostos em um delineamento de blocos ao acaso, com seis tratamentos e quatro repetiÃÃes. No primeiro experimento as plantas irrigadas com Ãgua ou soluÃÃo salina foram coletadas em diferentes Ãpocas do desenvolvimento da planta: 12, 42 e 55 dias apÃs a semeadura. Foram avaliados a CEes, teores de Cl-, Na+ e K+ do solo, parÃmetros de crescimento da planta (peso da matÃria seca das diferentes partes da planta, Ãrea foliar, altura e nÃmero de folhas), potenciais hÃdrico e osmÃtico e solutos inorgÃnicos. No segundo experimento, a Ãgua e a soluÃÃo salina foram aplicadas durante as seguintes fases de desenvolvimento da planta: FASE I â da germinaÃÃo atà o aparecimento da primeira folha trifoliolada; FASE II â do aparecimento da primeira folha trifoliolada atà o inÃcio da floraÃÃo; FASE III â da floraÃÃo atà a formaÃÃo completa das primeiras vagens, produzindo os seguintes tratamentos: 1. irrigaÃÃo com Ãgua atà o final da fase III; 2. irrigaÃÃo com soluÃÃo salina atà o final da fase III, 3. Ãgua atà o final da fase I e soluÃÃo salina atà o final da fase III, 4. soluÃÃo salina atà o final da fase I e Ãgua atà o final da fase III, 5.irrigaÃÃo com Ãgua atà o final da fase II e soluÃÃo salina atà o final da fase III, 6.irrigaÃÃo com soluÃÃo salina atà o final da fase II e Ãgua atà o final da fase III. Foram avaliados alÃm dos parÃmetros anteriores as trocas gasosas e os solutos inorgÃnicos. Os estÃdios de desenvolvimento mais afetados pela salinidade foram os de floraÃÃo e frutificaÃÃo. A parte aÃrea das plantas, em especial as folhas, sà foi afetada pela salinidade quando a mesma foi aplicada em mais de uma fase de crescimento, independente do estÃdio em que se iniciou o estresse. A taxa fotossintÃtica das plantas nÃo foi alterada pela salinidade em nenhum dos experimentos. Nas folhas, os carboidratos solÃveis nÃo sofreram influÃncia do estresse salino, enquanto os aminoÃcidos aumentaram quando o sal foi aplicado durante todo o perÃodo experimental. Nas raÃzes, ÃrgÃos que estavam em contato direto com o sal houve reduÃÃo tanto dos teores de proteÃnas quanto dos aminoÃcidos. O transporte de Na+ para a folha foi restringido, com o mesmo acumulando-se no caule, enquanto para o Cl- as plantas tiveram uma resposta tÃpica das glicÃfitas, com o maior teor deste Ãon nas folhas. A irrigaÃÃo de feijÃo de corda com soluÃÃo salina à possÃvel, desde que a mesma seja aplicada somente em parte do ciclo de crescimento da cultura, alternando com a aplicaÃÃo de Ãgua de qualidade superior.
The objective of this study the effects of water (CEw = 0.5 dS m-1) and saline solution (CEw = 5.0 dS m-1) applications, alternately, at different stages of development of cowpea cv. Epace 10. Two experiments were conducted under conditions of greenhouse in Embrapa AgroindÃstria Tropical. In both, seeds were placed into pots arranged in a randomized block design with six treatments and four replications. In the first experiment the plants irrigated with water or saline solution were collected at different times of development: 12, 42 and 55 days after sowing. CEes, as Cl-, Na + and K + in the soil, parameters of plant growth (dry weight of plant parts, leaf area, height and number of leaves), water potential and osmotic and inorganic solutes were evalueted. In the second experiment, water and saline solution were applied during the following stages of plant development: PHASE I - from germination to the appearance of the first trifoliolate leaf .PHASE II - the appearance of the first trifoliolate leaf until the beginning of flowering; PHASE III - flowering until the complete formation of the first pods, producing the following treatments: 1. irrigation with water until the end of phase III, 2. irrigation with saline solution until the end of Phase III, 3. water until the end of phase I and saline solution until the end of Phase III, 4. Saline solution until the end of phase I and water until the end of Phase III, 5.irrigation with water until the end of phase II and saline solution until the end of Phase III, 6.irrigation with saline solution until the end of phase II and water until the end of phase III. The parameters gas exchange and inorganic solutes were evaluated too. Flowering and fruiting stages were the most affected by salinity. The photosynthetic rate was not affected by salinity in plants shoots, especially leaves, when applied in more than one phase of growth, regardless of the stage where the stress began in both experiments. In leaves, the soluble carbohydrates were not affected by salt stress, while the amino acids increased when salt was applied throughout the experimental period. In roots, organs that were in direct contact with the salt decreased the levels of both proteins and amino acids. The transport of Na+ was restricted to the leaf with the same accumulated on the stem, while for the Cl- plants had a typical response of glycophyte with the highest level of this ion in the leaves. The cowpea irrigation with saline solution is possible, provided it is applied to only part of the cycle of crop growth, alternating with the application of water of superior quality.

The effects of spatial arrangement and density on agronomic efficiency, yield and yield components, dry matter partitioning and growth of an annual cotton/cowpea/maize intercrop were examined in 1990 and 1991 in Tucson, Arizona. The 1990 experiment consisted of four spatial arrangements crossed with four densities of cowpea and maize in a complete factorial design. The 1991 experiment consisted of two densities of cowpea and maize selected from the 1990 experiment in the best spatial arrangement crossed with five densities of cotton in a complete factorial design. A land use efficiency of 12% (or a land equivalent ratio of 1.12) was obtained in the spatial arrangement of single rows of cowpea and maize between singles rows of cotton, whereas a land use efficiency of 11% was obtained for cowpea and maize at a combined density of 50,000 plants/ha intercropped with cotton at a density of 50,000 plants/ha. Maize provided a greater contribution to the land use efficiency than either cotton or cowpea. Cotton yield was highest in the spatial arrangement of single rows of cowpea and maize between single rows of cotton. For the two food crops, cowpea yield was highest in the spatial arrangements in which cowpea and maize were grown in different rows between rows of cotton, whereas maize yield was highest in the spatial arrangements in which cowpea and maize were grown in the same rows between rows of cotton. Cotton fiber quality was not influenced by spatial arrangement, cowpea/maize density, and cotton density. Number of cowpea pods was affected by spatial arrangement in a manner similar to cowpea yield. Number of maize ears increased as cowpea/maize density increased, whereas number of kernels/ear, weight of 100 kernels and length of kernel rows decreased as cowpea/maize density increased. Dry matter accumulation in leaves, stems, and fruits of cotton and cowpea was greatest in the spatial arrangements in which cowpea and maize were grown in different rows between rows of cotton. Weekly cotton growth rate increased as cotton density increased from 39 to 74 days after sowing.

The study examined interactions between morogo plants, arbuscular mycorrhizal fungi (AMF) and Fusarium species. Morogo refers to traditional leafy vegetables that, together with maize porridge, are dominant staple foods in rural areas of the Limpopo Province such as the Dikgale Demographic Surveillance Site (DDSS). Morogo plants grow either as weeds (often among maize), occur naturally in the field or are cultivated as subsistence crops by rural communities. Botanical species of morogo plants consumed in the DDSS were determined. Colonisation of morogo plant roots by AMF and Fusarium species composition in the immediate soil environment were investigated in four of eight DDSS subsistence communities, Isolated AMF were shown to belong to the genera Acaulospora and Glomus. Twelve Fusarium species were isolated from soil among which Fusariurn verticilliodes and Fusarium proliferaturn occurred predominantly. Greenhouse pot trials were conducted to examine the effect of AMF on morogo plant growth (cowpea; Mgna unguiculata) and Fusarium proliferatum levels in soil, Interaction between plants and AMF, as well as tripartite interactions of cowpea plants, AMF and Fusarium proliferatum were investigated. Non-inoculated cowpea plants served as controls for the following inoculations of cowpea in pots: (i) Fusarium proliferatum; (ii) commercial AMF from Mycoroot (PTY) Ltd. (a mixture of selected indigenous Glomus spp referred to commercial AMF for the purpose of this study); (iii) indigenous AMF obtained from DDSS soil (referred to iocal AMF for the purpose of this study); (iv) commercial AMF plus Fusarium proliferatum; (v) local AMF plus Fusariurn proliferatum. Results showed reduced root colonization by local as well as commercial AMF when Fusarium proliferatum were present. Local AMF significantly enhanced cowpea growth while commercial AMF apparently reduced the level of Fusarium proliferatum in the rhizosphere and surrounding soil. Results suggest that AMF may have potential as biological growth enhancers and bioprotective agents against Fusarium proliferatum.
Thesis (M. Environmental Science (Water Science))--North-West University, Potchefstroom Campus, 2007.

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Fundação de Amparo a Pesquisa do Estado de Minas Gerais
The aim of this study was to analyze the growth and water use efficiency of maize and cowpea crops under different irrigation water depths in sole and intercropping systems in a semi-arid region. The experiment was carried out at the Experimental Field Station of Bebedouro (09 ° 09'S, 40 ° 22'W) Embrapa Semiarido, located at Petrolina-PE. The cowpea and maize in different cropping systems (sole and intercropping) were subjected to five different irrigation water depths applied shortly after tasseling in corn and flowering stage in cowpea 40 days after sowing. Combining the three settings of cropping systems and the five different irrigation water depths, the crops of maize and cowpea were subjected to 15 different treatments. Three different methods were used to obtain the values of crop coefficient (Kc): Soil water balance method, using the equation proposed by FAO bulletin 56, and Kc adjusted according to degree days values. To attain these objectives, the access tubes were settled down in each experimental treatment to a depth of 1.0 m for monitoring the soil water content in daily basis through an access tube model Diviner 2000 (Sentek Pty Ltd., Australia). The measurements were taken on weekly basis and the total biomass yield at the end of crop cycle (at 102 and 78 days for maize and cowpea, respectively). Morphophysiological indices were calculated to characterize the growth of corn and cowpea in different cropping systems. Indicators of the response of crop production and performance of water application in the cropping system were calculated by using data of total income, the relationship between the prices of commercial grain production for both crops, as well as amounts of precipitation (P) and volume of water applied by irrigation (I). The consortium has significantly reduced the total dry matter of shoots, leaf area index, the rate of crops growth, leaf weight and leaf area ratio of maize and cowpea. The coefficient of sole crop system showed values of 0.86, 1.10 and 0.52 for corn and 0.68, 1.04, 1.06 and 0.63 for cowpea, respectively, for phases beginning, middle and end. Intercropping system these values were 0.90, 1.30 and 0.72 for corn and 0.86 1.30 and 0.91 for cowpea, for these phases in the order they were mentioned. The grain yield of corn and cowpea in response to soil water availability was reduced in mixed stands in relation to unique plantings and water use efficiency of corn and cowpea planting was higher in exclusive compared to intercropping. Even so, in economic terms the adoption of the consortium was more advantageous in all treatments. This information is of great importance to support the improvement of water management in the Semiarid Northeast Brazil.
O objetivo desse trabalho foi analisar o crescimento, as necessidades hídricas e a eficiência do uso de água das culturas do milho e do feijão-caupi, submetidas a diferentes lâminas de água nos sistemas de plantio, exclusivo e consorciado, no Semiárido brasileiro. O experimento foi conduzido no Campo Experimental de Bebedouro (09°09 S; 40°22 W, 365,6m) da Embrapa Semiárido, localizado no município de Petrolina-PE. As culturas, nos diferentes sistemas de plantio (exclusivo e consorciado), foram submetidas a cinco lâminas de irrigação, aplicadas logo após o pendoamento no milho e na fase de floração do feijão-caupi aos 40 dias depois da semeadura. Combinando as configurações de sistema de cultivo e as diferentes lâminas de irrigação, as culturas do milho e do feijão-caupi foram submetidas a 15 tratamentos distintos. Foram utilizados três diferentes métodos para obtenção dos valores de coeficiente de cultura (Kc): balanço hídrico no solo, utilização da equação proposta pela FAO56 e ajuste da variável graus-dia aos valores de Kc. Para tanto, o monitoramento do teor de água no solo foi realizado diariamente por meio de uma sonda modelo Diviner 2000 (Sentek Pty Ltd., Austrália) e tubos de acesso instalados em cada tratamento. Realizaram-se medições de biomassa em intervalos semanais e de rendimento ao final do ciclo das culturas, que ocorreram aos 109 e 76 dias, para o milho e o feijão-caupi, respectivamente. Foram calculados índices morfofisiológicos para caracterizar o crescimento das culturas do milho e feijão-caupi nos diferentes sistemas de plantio. Além disso, foram utilizados indicadores que consideram a resposta produtiva da cultura e o desempenho de aplicação de água no sistema deprodução, que foram calculados por meio dos dados de rendimento total, da relação entre os preços da produção comercial de grãos de ambas as culturas, bem como dos valores de precipitação (P) e do volume de água aplicado por irrigação (I). O consorcio reduziu significativamente a fitomassa seca total da parte aérea, o índice de área foliar, a taxa de crescimento da cultura, a razão de massa foliar e a razão de área foliar do milho e feijão-caupi. O coeficiente de cultura em sistema exclusivo apresentou valores médios de 0,86, 1,10 e 0,52 para o milho e de 0,68, 1,04, 1,06 e 0,63 para o feijão-caupi, respectivamente para as fases inicial, intermediária e final. No sistema consorciado esses valores foram de 0,90, 1,30 e 0,72 para o milho e 0,86, 1,30 e 0,91 para o feijão-caupi, para as referidas fases na ordem que foram mencionadas. A produtividade de grãos das culturas do milho e feijão-caupi em resposta à disponibilidade hídrica no solo foi reduzida nos plantios consorciados em relação aos plantios exclusivos e a eficiência de uso de água das culturas do milho e do feijão-caupi foi superior no plantio exclusivo em relação ao consorciado. Mesmo assim, em termos econômicos a adoção do consórcio mostrou ser mais vantajosa em todos os tratamentos. Essas informações são de grande importância para subsidiar a melhoria do manejo da água no Semiárido do Nordeste brasileiro.

Seaweed extracts are known to have a stimulatory effect on the growth and development of plants. This study investigated the effect of applying a commercial seaweed concentrate (kelpak) on rhizobia growth (Bradyrhizobium strain CB756 and Bradyrhizobium japonicum strain CB 1809) and nitrogen fixation in cowpea ( Vigna ungulata L. Walp.) and soybean (Glycine ma.x L. Merr.) plants. Two concentrations of Kelpak (1:100 v/v and 1:500 v/v seaweed concentrate dilutions) were applied to pots with seeds or seedlings at sowing and after every 14 days (1:l00A; 1:500A), at sowing and after every 7 days (1:100B; 1:500B) or after germination and after every 14 days (1: l00C; 1:500C). From the first experiment, cowpea plants in the various treatments showed no change in shoot biomass. The root biomass was significantly inhibited in treatment 1:100B relative to the control. The nodule dry matter of cowpea was reduced in 1:100A, 1:100B and 1:100C Kelpak concentrations compared to control, with a significant increase only in 1:100B Kelpak concentration. As a result, cowpea plants showed the highest total biomass in 1:500B treatment. Although shoot N in cowpea plants remained unchanged under the various kelpak treatments, root N was significantly reduced. Soybean plants showed a significant decrease in shoot and root biomass compared to the control. Nodule dry matter was lowest for soybean plants in Kelpak treatments 1:500B, 1:100B and 1:100C. As a result, there was a decrease in soybean total growth in treatment 1:500B compared to the control. Total N in shoots and roots was highest in soybean plants growing in 1:500A relative to the control. Culturing cells of Bradyrhizobium strain CB756 with Kelpak showed a significant increase in growth at 1:100 and 1:500 dilutions compared to the control. However, over the 93 h period with sterile Kelpak culture there was an inhibition in growth of strain CB756 relative to the control. Beyond the 93 h there was a significant increase in growth of Bradyrhizobium japonicum strain CB 1809 in all Kelpak treatments. The 1:100 concentration showed the highest bacterial growth compared to the control and the other treatments. These data suggests the presence of an active molecule in Kelpak that stimulates rhizobial growth and its symbiotic interaction with legumes.

Cowpea (Vigna unguiculata L.) is an important legume, especially in the hot, dry tropics and subtropics of sub-Saharan Africa. It has been widely reported to be drought tolerant. Cowpea is a highly nutritious, multi-purpose crop, used as a leafy vegetable and grain legume with potential to contribute to food security in marginal areas. However, the crop is still classified as a neglected underutilised species; legume research focus has been mainly devoted to established legumes such as common bean and soybeans. There is a need to collect empirical information on cowpea which could be used to advise farmers on management strategies. This study evaluated cowpea responses to water stress under controlled and field conditions. Initially, two cowpea varieties (Brown and White birch) were evaluated for seed quality using the standard germination that was laid out in a completely randomised design and each variety was replicated for times. Electrolyte conductivity test was also performed under laboratory conditions. Thereafter, a pot trial was conducted to evaluate cowpea response to water stress imposed at different growth stages under varying growth temperatures. The pot trial comprised three factors: temperature [High (33/27ºC), Optimum (27/21ºC) and Low (21/15ºC)], water regimes (no stress, terminal stress, intermittent stress – vegetative and intermittent stress - flowering) and cowpea varieties. Lastly, a field trial was conducted to evaluate cowpea production as well as the effect of sequential leaf harvesting on yield under irrigated and rainfed conditions. The field trial was laid out as a split-plot design, with water regime (irrigation vs. rainfed) as main factors, cowpea varieties as sub-factor and sequential harvesting (no harvest, harvested once and harvested twice), replicated three times. All treatments were arranged in a randomised complete block design. Results of the initial study showed that germination capacity and vigour of cowpea varieties were significantly different (P < 0.001). White birch had higher electrolyte leakage than Brown birch. Pot trial results showed that cowpea growth (leaf area, leaf number and plant height) was vigorous in the high temperature regime compared with optimum and low temperature regimes. Chlorophyll content index was higher under high temperature relative to optimum and low temperature regimes, respectively. Under low and optimum temperature regimes, cowpea growth was stunted; cowpea failed to flower and form yield. Whereas, under high temperature regime, cowpea growth was vigorous hence flowered and formed yield. Vegetative growth was more sensitive to water stress than flowering stage. Terminal stress and stress imposed during flowering resulted in increased proline accumulation relative to no stress and stress imposed during vegetative growth. Harvest index was lower when water stress was imposed during vegetative relative to flowering stage. Field trial results showed that cowpea growth was sensitive to water stress. Plant height, leaf number, chlorophyll content index and stomatal conductance were lower under rainfed relative to irrigated conditions. Sequential harvesting of leaves had no significant effect on cowpea yield. It is concluded that tropical temperature conditions are most suitable for cowpea production; the controlled environment study showed best crop performance under 33/27ºC. In the context of varieties used for the present study, vegetative growth was the most sensitive stage to water stress. Cowpea performed better under rainfed relative to irrigated conditions with respect to yield formation. Low temperature was found to be more limiting to cowpea growth, development and productivity compared with water stress. Whereas, under high temperature conditions, water stress was more limiting to plant growth and productivity. White birch may be used as a dual purpose crop due to its ability to produce reasonable grain yield regardless of defoliation.
Thesis (M.Sc.Agric)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

碩士
國立中興大學
土壤環境科學系所
101
The production of nitrogen fertilizer is the most energy consuming activity in agricultural sector. A good symbiotic nitrogen fixation bacteria can contribute main part of nitrogen requirement for legume crops. In Taiwan, there was few reports about cowpea symbiotic bacteria. In preliminary experiment, the growth of cowpea was seriously inhibited in non pH adjusted vermiculite medium. The purposes in this thesis were: First to isolate and identify the cowpea symbiotic nitrogen fixation bacteria for cowpea at first. Secondly, to develop a suitable culture medium formula for easier handle in bacteria re-inoculation test. Thirdly, to evaluate the plant promoting ability of the bacteria selected on the growth of cowpea in indoor controlled system, greenhouse, and field experiments. Last, to evaluate the effect of the fungicide and nitrogen fertilizer on the efficiency of the selected cowpea symbiotic nitrogen fixation bacteria. There were 7 effective cowpea symbiotic nitrogen fixation strains selected from 49 soil samples by using cowpea cultivar 101. MY2-23(2) strain is Ensifer sp. and six strains are Bradyrhizobium sp.. Nodule growth showed strain TY5 had largest number of nodules per plant, strain 6243 had the highest fresh nodule weight per plant. MY2-23(2) showed the highest ethylene reduction ability in 890 nmole C2H4 plant-1 hr-1 and 8715 nmole C2H4 g-1 hr-1. The 7 selected strains were cultured in pH of Yeast Extract Medium (YEM) at 4.8, 5.8, 6.8, 7.8, 8.8 and their growth were detected under O.D. 600. The results showed MY2-23(2) and 632 strains were grown better in alkaline range, DL4(2), TY5, 6242, 6243 strains were grown better in neutral range, PT2 strain was grown better in acid range, growth well in pH 4.8. In salinity tolerance test, the selected strains were cultured in YEM prepared in 0.02, 1, 3, 5, and 7% NaCl strengths. The results showed MY2-23(2)、PT2 can growth in 1% NaCl YEM solution. DL4(2)、 TY5、 6242、6243、632 can growth only in 0.02% NaCl YEM solution. In culture medium experiment, peat, perlite, agar, and acidified vermiculite were used in growing cowpea inoculated with the selected strain. The growth of cowpea in vermiculite medium was inhibited even whose pH was already pre-acidified, the growth of cowpea other three media were acceptable. However, it seems more convenient as cowpea growing in agar medium for easier observing the development of nodule for its partial transparent character. Additionally, peat used in this study containing more available nitrogen than other media but the number of nodules formed didn’t reduce in significant level. An extra potassium source added with 4.38 g L-1 chloride potassium into nutrient solution which can rise the fresh and dry weights significantly but reduce the ability of ethylene reduction and number of nodules. Three cowpea cultivars (101, 131, and white) and two nitrogen fixation bacteria (TY5, MY2-23(2)) were used to examine the cross infection between the cowpea and strains although both strains were selected through cultivar 101. In the result of inoculation, 101 had more fresh and dry weights inoculated by MY2-23(2), and cultivar 131 had more fresh weights and cultivar White had more dry weights as inoculated by TY5. The ethylene reduction ability of MY2-23(2) and TY5 strains in cultivar 131 were better than in cultivar 101. The combination effects of nitrogen fertilizer, nitrogen fixation bacteria, and fungicide on cowpea growth were examined in factorial combination of these three factors in pot and field experiments. In pot experiment, results showed that a higher fresh and dry weights in inoculating treatments no matter with nitrogen application or or not. In field experiment, although the formed nodules in inoculating treatments is higher, but lower cowpea pod productions was found. This may be due to the cowpea is not suitable for the winter season and more nodules may consume more carbohydrate from the host or may be the native nitrogen fixation bacteria is more efficient in nitrogen fixation than the introduced bacterium. The use of fungicide showed a decrease of the nodule formation. The disease severity of powdery mild were decreased by applying fungicide and cowpea nitrogen fixation bacteria. This will be a good practice in plant disease control and worth to pay attention to.

"February 2003"
Bibliography: leaves 160-174.
xi, 174 leaves : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
This study assessed separately the effects of Aluminium and of low pH on the growth of gigaspora margarita and its symbiotic function in the growth of cowpea (vigna unguiculata L. Walp,).
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2003

Thesis (MSc. Agriculture(Soil Science) -- University of Limpopo, 2018
Soil acidity is one of the abiotic stress factors that greatly limit the productivity of crops on farmers’ fields. A greenhouse study was carried out over two summer growing seasons to evaluate the effect of lime and phosphorus (P) application rates on the growth, yield and root attributes of a determinate cowpea variety on acid soil. The experiment was laid out as a 4x5 factorial arrangement with 4 replications. Treatment factors comprised of variable rates of Vaalburg dolomitic lime (0, 2, 4 and 6 t ha-1) and P (0, 15, 30, 45 and 60 kg ha-1) using single super phosphate, 10.5% P. The two treatment factors were combined resulting in a total of 20 treatment combinations. Data collected included cowpea growth parameters, crop phenology, yield attributes and root characteristics. While cowpea plants with no P application consistently gave the least plant height, stem diameter, number and length of trifoliate leaves, the 6 t ha1 lime rate appears to be completely disadvantaged for all measured parameters with generally lower values than in soil filled pots without lime application. Results showed that soil pH was increased with 6 t ha-1 lime application while soil electrical conductivity (EC), percent of organic matter (OM) and total organic carbon (TOC) were all increased with increasing P and lime rates. All measured cowpea growth attributes such as plant height, stem diameter, number of trifoliate leaves, and leaf area were significantly increased (p≤0.05) with increasing P and lime rates. During the two planting seasons, P and lime application resulted in reduced (p≤0.05) duration to flowering, pod formation and physiological maturity. The 6 t ha-1 lime application produced higher number of pods (2.50) compared to the other rates. Application rates of 45 kg P ha-1 and 6 t ha-1 of lime produced superior number of seeds per pod with high values of (13.71) and (12.85), respectively. However, cowpea root attributes namely number of nodules per plant, the third branching root diameter, angle of adventitious root, tap root diameter at 5 and 10 cm, shallow and deep score were significantly increased at moderate P rate of 30 kg P ha-1. Overall, findings of this study revealed that application of both P fertiliser and lime were able to ameliorate the negative effect of P deficiency from soil acidity on the evaluated cowpea variety and promoted increased yield. Keywords: Acid soil, grain cowpea, P fertiliser, lime, growth, root characteristics, yield
National Research Foundation (NRF) and Department of Agriculture, Forestry and Fisheries (DAFF)

This study’s main goal was to evaluate Bacillus subtilis inoculation and mine water irrigation effect on germination, growth, nodulation, physiology and shoot/grain quality of cowpea genotypes exposed to extreme climatic conditions (elevated temperatures). The first experiment evaluated the interactive effect of Bacillus subtilis (BD233) inoculation and elevated temperature on germination indices and plumule lengths of three genotypes (Asetanapa, Soronko and Nyira) of cowpea. The results showed that interaction between B. subtilis (BD233) and temperature significantly (p<0.05) influenced the germination indices (germination percentage (G%), germination index (GI) and germination rate index (GRI)) and plumule length of cowpea seedlings and genotype responses were significantly different. At elevated temperature (35oC), inoculation with B. subtilis (BD233) enhanced seed germination and growth of cowpea. The second experiment evaluated the effect of temperature on growth and nutritional content of cowpea incubated for seven days in a growth chamber. The results showed that when cowpea genotype, Soronko, was incubated at different temperature regimes, the whole plant biomass, shoot carbon and crude protein contents were significantly affected with temperature increases at all three stages of the plants’ life cycle. The results suggest that the pre-flowering (40 DAP) and flowering (90 DAP) stages of cowpea compared to post-flowering (123 DAP) are more susceptible to elevated temperatures (30-35oC). The third experiment evaluated Bacillus subtilis inoculation and mine water irrigation effect on growth, nodulation, physiology and nutritional content of cowpea under glasshouse conditions. The results revealed that the interaction of B. subtilis (BD233) inoculation and mine water (75% AMD) irrigation was significant for the growth, nodulation, stomatal conductance, chlorophyll contents and shoot/grain nutritional quality of cowpea genotypes. In comparison with control, generally, B. subtilis inoculation enhanced the growth, nodulation and yield of all tested cowpea genotypes and irrigation with mine water significantly influenced the mineral contents in both shoot and grain of cowpea. Taken together, findings in this study have implications for cultivation of cowpea, an important candidate for food/nutrition security in Africa, under future climate change scenarios.
Environmental Sciences
M. Sc. (Environmental Sciences)

碩士
國立清華大學
材料科學工程學系
95
This work is focused on the optimization on the composition and structure of electroless CoWP catalyst to enhance the carbon nanowire growth for interconnect application. The blanket (Cu/Ti/SiO2/Si) wafers were used to optimize the electroless plating process of CoWP for carbon nano-wire (CNW) growth. The structure wafers (provided by TSMC) with 70 nm via and Cu line underneath were used to measure via- resistance after CNW growth. The pH value, plating temperature, and plating time were optimized to modify the morphology of CoWP for CNW growth. Besides, the effect of W concentration on CNW growth was also investigated. The CNWs were grown by the chemical vapor deposition (CVD) at 400 oC, using C2H2 as a reaction gas at 0.05 – 2.5 Torr with Ar as a carrier gas and H2 to activate the catalyst. For CNW-via resistance measurement, Pt was deposited on the CNW-via by focus-ion-beam technique. The CNW-via resistance was measured by Multi-Probe Nano-Electronics Measurement (MPNEM) system. The ohmic behavior and a resistance of 7.2k Ω/via of CNW-vias was measured, which needs further improvement for future interconnect application.