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Made available in DSpace on 2014-06-11T19:22:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-20Bitstream added on 2014-06-13T19:27:21Z : No. of bitstreams: 1 cruz_cs_me_botfca.pdf: 432313 bytes, checksum: 67b704c172a7ce4307b2fa05c723a8bc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The search for an ecologically sustainable and economically viable agriculture is growing through the years. Conservation tillages and production systems that aim maximizing soil and water use in a sustainable form, has becoming alternatives, mainly for regions that have relatively short periods of rain and high temperatures. The objective of this research was to evaluate intercropping systems with maize and Brachiaria that has better adaptation to the edaphoclimatic conditions in Zona da Mata region, State of Alagoas. The experiment was conducted in 2005, in the experimental area of Campus Delza Gitaí belonging to the Centro de Ciências Agrárias - CECA, Universidade Federal de Alagoas - UFAL. The treatments consisted of a BRS 3150 hybrid of maize, cultivated in the systems: 1) Conventional Cropping, 2) Minimum Cultivation and 3) No-tillage (BRS 3150 intercropped with Brachiaria decumbens). The randomized block design was used, with subdivided splots and four replications, with an area of 44.8 m2 (6.4 x 7 m) for each subplot. During maize flowering period, it was measured plant height, stem diameter and number of photosynthetic active leaves; for these evaluations... (Complete abstract click electronic access below)

Thesis (M.Sc. (Agriculture)) --University of the North, 1985 / Refer to the document / University of the North, HSRC (Human Science Research Council), and Lebowa Project Committee

Thesis (MSc. (Agriculture)) --University of Limpopo, 2011 / Maize is the most important cereal crop grown in South Africa. This crop is produced throughout the country under diverse environments. The study only focuses on the technical efficiency because it is an important subject in developing agriculture where resources are limited, but high population growth is very common. Technical efficiency is the ability of a farmer to obtain output from a given set of physical inputs. Farmers have a tendency of under and/or overutilising the factors of production. The main aim of this study was to analyse the technical efficiency of small-scale maize producers in Ga-Mothiba rural community of Limpopo Province. The objective of the study was to determine the level of technical efficiency of smallscale maize producers and to identify the socio-economic characteristics that influence technical efficiency of small-scale maize producers in Ga-Mothiba. Purposive and Snowball sampling techniques were used to collect primary data from 120 small-scale farmers. Cobb-Douglas production function was used to determine the level of technical efficiency and Logistic regression model was used to analyse the variables that have influence the technical efficiency of maize production. Cobb-Douglas results reveal that small-scale farmers in Ga-Mothiba are experiencing technical inefficiency in maize production due to the decreasing return to scale, which means they are over-utilising factors of production. Logistic regression results indicate that out of 13 variables included in the analysis as socio-economic factors, 10 of them (level of education, income of the household on monthly basis, farmer`s farming experience, farm size, cost of tractor hours, fertiliser application, purchased hybrid maize seeds, membership to farmers` organisation, is maize profitable) were found to be significant and 3 (gender, age and hired labour) are non-significant. However, farm size was found to be the vi most significant variable at 99% level, showing a positive relationship to smallscale maize producer`s technical efficiency. Therefore, it is recommended that government should do the on-farm training since farmers mainly depend on trial and error and farmers` should have access to enough arable land and tractor services. However, farmers need to be trained on matters relating to fertiliser application, on the amount of seeds a farmer should apply per ha, and the importance of using hybrid seed.

Thesis (M.Agric. (Agricultural Economics)) --University of Limpopo, 2011 / Maize is the most important cereal crop grown in South Africa. This crop is produced throughout the country under diverse environments. The study only focuses on the technical efficiency because it is an important subject in developing agriculture where resources are limited, but high population growth is very common. Technical efficiency is the ability of a farmer to obtain output from a given set of physical inputs. Farmers have a tendency of under and/or over- utilising the factors of production. The main aim of this study was to analyse the technical efficiency of small-scale maize producers in Ga-Mothiba rural community of Limpopo Province. The objective of the study was to determine the level of technical efficiency of small- scale maize producers and to identify the socio-economic characteristics that influence technical efficiency of small-scale maize producers in Ga-Mothiba. Purposive and Snowball sampling techniques were used to collect primary data from 120 small-scale farmers. Cobb-Douglas production function was used to determine the level of technical efficiency and Logistic regression model was used to analyse the variables that have influence the technical efficiency of maize production. Cobb-Douglas results reveal that small-scale farmers in Ga-Mothiba are experiencing technical inefficiency in maize production due to the decreasing return to scale, which means they are over-utilising factors of production. Logistic regression results indicate that out of 13 variables included in the analysis as socio-economic factors, 10 of them (level of education, income of the household on monthly basis, farmer`s farming experience, farm size, cost of tractor hours, fertiliser application, purchased hybrid maize seeds, membership to farmers` organisation, is maize profitable) were found to be significant and 3 (gender, age and hired labour) are non-significant. However, farm size was found to be the most significant variable at 99% level, showing a positive relationship to small- scale maize producer`s technical efficiency.Therefore, it is recommended that government should do the on-farm training since farmers mainly depend on trial and error and farmers` should have access to enough arable land and tractor services. However, farmers need to be trained on matters relating to fertiliser application, on the amount of seeds a farmer should apply per ha, and the importance of using hybrid seed.

Thesis (M.Sc. Agric.) --University of Limpopo, 2011 / Maize is the most important cereal crop grown in South Africa. This crop is produced throughout the country under diverse environments. The study only focuses on the technical efficiency because it is an important subject in developing agriculture where resources are limited, but high population growth is very common. Technical efficiency is the ability of a farmer to obtain output from a given set of physical inputs. Farmers have a tendency of under and/or over- utilising the factors of production. The main aim of this study was to analyse the technical efficiency of small-scale maize producers in Ga-Mothiba rural community of Limpopo Province. The objective of the study was to determine the level of technical efficiency of small- scale maize producers and to identify the socio-economic characteristics that influence technical efficiency of small-scale maize producers in Ga-Mothiba. Purposive and Snowball sampling techniques were used to collect primary data from 120 small-scale farmers. Cobb-Douglas production function was used to determine the level of technical efficiency and Logistic regression model was used to analyse the variables that have influence the technical efficiency of maize production. Cobb-Douglas results reveal that small-scale farmers in Ga-Mothiba are experiencing technical inefficiency in maize production due to the decreasing return to scale, which means they are over-utilising factors of production. Logistic regression results indicate that out of 13 variables included in the analysis as socio-economic factors, 10 of them (level of education, income of the household on monthly basis, farmer`s farming experience, farm size, cost of tractor hours, fertiliser application, purchased hybrid maize seeds, membership to farmers` organisation, is maize profitable) were found to be significant and 3 (gender, age and hired labour) are non-significant. However, farm size was found to be the most significant variable at 99% level, showing a positive relationship to small- scale maize producer`s technical efficiency. Therefore, it is recommended that government should do the on-farm training since farmers mainly depend on trial and error and farmers` should have access to enough arable land and tractor services. However, farmers need to be trained on matters relating to fertiliser application, on the amount of seeds a farmer should apply per ha, and the importance of using hybrid seed.

The U.S. is the largest maize producer in the world with a production of 300 million tons in 2012. Approximately 86% of the maize production is focused on the Midwestern states. The rest of the production is focused in the Southern states, where Texas is the largest maize producer. Grain yield in Texas ranges from 18 tons/ha in the irrigated production zones to 3 tons/ha in the dryland production zones. As a result, grain yield has increased slowly because of the poor production in the non-irrigated acres. Methods to improve the grain yield in Texas is to breed for maize varieties adapted to Texas growing conditions, including mapping genes that can be incorporated into germplasm through marker assisted selection. This dissertation includes two separate projects that exploit historical data and maize diversity to increase grain yield in Texas. For the first project, a large dataset collected by Texas AgriLife program was analyzed to elucidate past trends and future hints on how to improve maize yield within Texas. This study confirmed previous reports that the rate of increase for grain yield in Texas is less than the rate observed in the Midwestern US. For the second project, a candidate gene and whole genome association mapping analysis was performed for drought and aflatoxin resistance in maize. In order to do so, maize inbred lines from a diversity panel were testcrossed to isogenic versions of Tx714. The hybrids were evaluated under irrigated and non-irrigated conditions. The irrigated trials were inoculated with Aspergillus flavus and the aflatoxin level was quantified. This study found that the gene ZmLOX4 was associated with days to silk, and the gene ZmLOX5 gene was associated with plant and ear height. In addition, this study identified 13 QTL variants for grain yield, plant height, days to anthesis and days to silk. Furthermore, this study shows that diverse maize inbred lines can make hybrids that out yield commercial hybrids under heat and drought stress. Therefore, there are useful genes present in these diverse lines that can be exploited in maize breeding programs

Orientador: Silvio José Bicudo / Banca: Abel Washington de Albuquerque / Banca: José Roberto Santos / Abstract: The search for an ecologically sustainable and economically viable agriculture is growing through the years. Conservation tillages and production systems that aim maximizing soil and water use in a sustainable form, has becoming alternatives, mainly for regions that have relatively short periods of rain and high temperatures. The objective of this research was to evaluate intercropping systems with maize and Brachiaria that has better adaptation to the edaphoclimatic conditions in "Zona da Mata" region, State of Alagoas. The experiment was conducted in 2005, in the experimental area of "Campus Delza Gitaí" belonging to the "Centro de Ciências Agrárias - CECA, Universidade Federal de Alagoas - UFAL". The treatments consisted of a BRS 3150 hybrid of maize, cultivated in the systems: 1) Conventional Cropping, 2) Minimum Cultivation and 3) No-tillage (BRS 3150 intercropped with Brachiaria decumbens). The randomized block design was used, with subdivided splots and four replications, with an area of 44.8 m2 (6.4 x 7 m) for each subplot. During maize flowering period, it was measured plant height, stem diameter and number of photosynthetic active leaves; for these evaluations... (Complete abstract click electronic access below) / Mestre