A study was conducted to investigate the influence of planting methods and tuber weight on growth and yield of local yam cultivars obtained by the minisett technique from white yam (D. rotundata) in Gabon. Trials were carried out in 2014 and 2015 at the experimental ground of the Higher National Institute of Agronomy and Biotechnology, under natural conditions of lightness, temperature and relative humidity. Twentyfour weeks old mini tubers obtained from local cultivar MVA of D. rotundata were harvested, weighed and categorized (40-80g; 100-150g; 200-300g), and three planting methods (horizontal, oblique and vertical),arranged in ridges constituted the main factors. The experiment was laid out in Randomized Completely Block Design with eighteen treatments and two replications. Data pertaining to sprouting were recorded for 30, 60, 90 and 180 DAP, for tuber length (cm), tuber weight (Kg) and number of tubers per plant 270 DAP. Significant differences among tuber weight in all variables tested were observed. The larger tubers had better sprouting ability than the rest of the tuber weight. The methods of planting had no effects on yield and its components but they affect the depth and spread of tubers. Vertical planting produced deeper but more compactly arranged tubers while horizontal planting produced tubers which were shallower but more widespread. Slanting was intermediate for both depth and spread. The number and weight of tubers obtained from mini tubers planted out according to slanting method were significantly different (P< 0.05) from other planting methods. The production of seedlings from mini tuber is an improvement of traditional production of seed yam. Mini tubers must have at least 100-300 g and they should be planted slanting or vertically.
{"title":"Effects of planting methods and tuber weights on growth and yield of yam cultivars (Dioscorea rotundata Poir.) in Gabon","authors":"P. O. Ovono, C. Kevers, J. Dommes","doi":"10.14303/IRJAS.2016.025","DOIUrl":"https://doi.org/10.14303/IRJAS.2016.025","url":null,"abstract":"A study was conducted to investigate the influence of planting methods and tuber weight on growth and yield of local yam cultivars obtained by the minisett technique from white yam (D. rotundata) in Gabon. Trials were carried out in 2014 and 2015 at the experimental ground of the Higher National Institute of Agronomy and Biotechnology, under natural conditions of lightness, temperature and relative humidity. Twentyfour weeks old mini tubers obtained from local cultivar MVA of D. rotundata were harvested, weighed and categorized (40-80g; 100-150g; 200-300g), and three planting methods (horizontal, oblique and vertical),arranged in ridges constituted the main factors. The experiment was laid out in Randomized Completely Block Design with eighteen treatments and two replications. Data pertaining to sprouting were recorded for 30, 60, 90 and 180 DAP, for tuber length (cm), tuber weight (Kg) and number of tubers per plant 270 DAP. Significant differences among tuber weight in all variables tested were observed. The larger tubers had better sprouting ability than the rest of the tuber weight. The methods of planting had no effects on yield and its components but they affect the depth and spread of tubers. Vertical planting produced deeper but more compactly arranged tubers while horizontal planting produced tubers which were shallower but more widespread. Slanting was intermediate for both depth and spread. The number and weight of tubers obtained from mini tubers planted out according to slanting method were significantly different (P< 0.05) from other planting methods. The production of seedlings from mini tuber is an improvement of traditional production of seed yam. Mini tubers must have at least 100-300 g and they should be planted slanting or vertically.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76552483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heat waves have become more frequent as global warming continues to raise the average temperature of the earth. This study investigated the annual average trend and variability of atmospheric temperature in Ijebu-Ode, Southwest Nigeria. Secondary data of atmospheric air temperature was obtained from the Nigeria Meteorological agency (NIMET) Ijebu-Ode, Ogun state station, which covers thirty-one (31) years. Both parametric (Least Square Regression) and non parametric (Mann Kendall) test was performed on the data to investigate the trends, while variability was investigated using the ttest statistics and standardized index. The analysis of result revealed that temporal air temperature trend has remained generally on the increase since 1983. The increase was gradual between 1991 and 2013. A slight drop in temperature was experienced between the late 1984 and 1985. Thereafter, the gradual increase continued until date. Both least square regression and Mann Kendall test showed that the increasing trend was significant. Stakeholders ranging from government, individuals and cooperate bodies have been encouraged to take the issue of climate variability serious in the study area and Southwest Nigeria in general.
{"title":"Analysis of trend and variability of atmospheric temperature in Ijebu-Ode, Southwest Nigeria","authors":"A. Oluwatobi, O. Oluwakemi","doi":"10.14303/IRJAS.2016.013","DOIUrl":"https://doi.org/10.14303/IRJAS.2016.013","url":null,"abstract":"Heat waves have become more frequent as global warming continues to raise the average temperature of the earth. This study investigated the annual average trend and variability of atmospheric temperature in Ijebu-Ode, Southwest Nigeria. Secondary data of atmospheric air temperature was obtained from the Nigeria Meteorological agency (NIMET) Ijebu-Ode, Ogun state station, which covers thirty-one (31) years. Both parametric (Least Square Regression) and non parametric (Mann Kendall) test was performed on the data to investigate the trends, while variability was investigated using the ttest statistics and standardized index. The analysis of result revealed that temporal air temperature trend has remained generally on the increase since 1983. The increase was gradual between 1991 and 2013. A slight drop in temperature was experienced between the late 1984 and 1985. Thereafter, the gradual increase continued until date. Both least square regression and Mann Kendall test showed that the increasing trend was significant. Stakeholders ranging from government, individuals and cooperate bodies have been encouraged to take the issue of climate variability serious in the study area and Southwest Nigeria in general.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"45 1","pages":"25-31"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79497697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite the fact that Coffee (Coffeaarabica) is one of the most consumed beverages in the world and it is second largest traded commodity after petroleum (Mussato et al., 2011). It is highly economical but its production in Nigeria is fast declining as a result of inadequate processing technologies necessary to help eliminate the high level of drudgery associated with manual dehulling and polishing of coffee beans (Gbabo et al., 2013). For the purpose of eliminating the drudgery, increasing both the quantity and quality of coffee beans production, the National Centre for Agricultural Mechanization (NCAM) Ilorin designed and developed a machine for depulping freshly harvested coffee and a machine for polishing dried coffee beans.
尽管咖啡(Coffeaarabica)是世界上消费最多的饮料之一，也是仅次于石油的第二大贸易商品(Mussato et al.， 2011)。它是高度经济的，但其在尼日利亚的产量正在迅速下降，因为没有足够的加工技术来帮助消除与手工去皮和抛光咖啡豆相关的高水平苦差事(gabbo等人，2013)。为了消除苦差事，提高咖啡豆生产的数量和质量，伊洛林国家农业机械化中心(NCAM)设计并开发了一台新收获的咖啡脱浆机和一台抛光干咖啡豆的机器。
{"title":"Performance evaluation of NCAM developed coffeedepulping machine","authors":"Jackson B.A, T. Faleye, Agaja M.O, Mofolasayo A.S","doi":"10.14303/IRJAS.2016.010","DOIUrl":"https://doi.org/10.14303/IRJAS.2016.010","url":null,"abstract":"Despite the fact that Coffee (Coffeaarabica) is one of the most consumed beverages in the world and it is second largest traded commodity after petroleum (Mussato et al., 2011). It is highly economical but its production in Nigeria is fast declining as a result of inadequate processing technologies necessary to help eliminate the high level of drudgery associated with manual dehulling and polishing of coffee beans (Gbabo et al., 2013). For the purpose of eliminating the drudgery, increasing both the quantity and quality of coffee beans production, the National Centre for Agricultural Mechanization (NCAM) Ilorin designed and developed a machine for depulping freshly harvested coffee and a machine for polishing dried coffee beans.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"44 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88274551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In irrigated farm lands of the Republic of Uzbekistan mung bean is grown as the main and repeated crop. In the component of bean 25 –31% of protein, it requires needs of food of the population, its straw is nutrient feed for stock – breeding. How much the area extends which planted mung bean (it is given simple bean), it will play an essential role of malnutrition of protein.
{"title":"Measures against diseases of mung bean","authors":"Rahmonov Jx, Sheraliev A.Sh","doi":"10.14303/IRJAS.2016.022","DOIUrl":"https://doi.org/10.14303/IRJAS.2016.022","url":null,"abstract":"In irrigated farm lands of the Republic of Uzbekistan mung bean is grown as the main and repeated crop. In the component of bean 25 –31% of protein, it requires needs of food of the population, its straw is nutrient feed for stock – breeding. How much the area extends which planted mung bean (it is given simple bean), it will play an essential role of malnutrition of protein.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"36 1","pages":"43-46"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83425973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To valorise sediments of iron mineral extraction zone of about 2500ha of coverage in Liberia, a concept of appropiate fertilizer was developed. A comparative study was carried out on two types of soil : a soil riched in organic matter called arable land and a soil formed exclusively with sediments called sediments or Tailings Pond. The results revealed that the choice of fertilizer types and forms played an important role in yield increase. Therefore, the best yields were obtained with the combination of the different forms of Nitrogen fertilizers and different forms of calcium and potassium fertilizers. The use of sawdust as supportive organic matter, from the different combinations, has increased or dercreased the yields of the two types of soils.
{"title":"Chlorite effects compared to sulfate in combination with forms of nitrogen on yields of oat and Chinese cabbage","authors":"Avonyo K.A","doi":"10.14303/irjas.2016.019","DOIUrl":"https://doi.org/10.14303/irjas.2016.019","url":null,"abstract":"To valorise sediments of iron mineral extraction zone of about 2500ha of coverage in Liberia, a concept of appropiate fertilizer was developed. A comparative study was carried out on two types of soil : a soil riched in organic matter called arable land and a soil formed exclusively with sediments called sediments or Tailings Pond. The results revealed that the choice of fertilizer types and forms played an important role in yield increase. Therefore, the best yields were obtained with the combination of the different forms of Nitrogen fertilizers and different forms of calcium and potassium fertilizers. The use of sawdust as supportive organic matter, from the different combinations, has increased or dercreased the yields of the two types of soils.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"39 1","pages":"20-24"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77938989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The relationship between agriculture and forestry is a recurring theme in tropical regions where forest areas are replaced by agricultural land. In this study, the main objective is to analyze the relationship between deforestation and agricultural productivity in Cote d’Ivoire. In our methodological process, a formal theoretical framework is examined before specifying the empirical model. In the first step, an optimal control model is used to determine the optimal steady-state forest stock in Cote d’Ivoire. In the second step, an error correction model is used to analyze long run and short run relations between deforestation and agricultural productivity. Data for the empirical model were obtained from World Bank and FAO statistical database. The estimates showed that the agricultural yield responds significantly and negatively to deforestation. Indeed, a 1 per cent rise in deforestation rate will lead to about 5 per cent decline in agricultural yield. The fact that deforestation accelerates soil erosion and thus shifts agriculture to less suitable areas explains this result.
{"title":"An analysis of dynamics of deforestation and agricultural productivity in Côte d'Ivoire.","authors":"Béké Tite Ehuitché","doi":"10.2307/j.ctvh9vtc7.10","DOIUrl":"https://doi.org/10.2307/j.ctvh9vtc7.10","url":null,"abstract":"The relationship between agriculture and forestry is a recurring theme in tropical regions where forest areas are replaced by agricultural land. In this study, the main objective is to analyze the relationship between deforestation and agricultural productivity in Cote d’Ivoire. In our methodological process, a formal theoretical framework is examined before specifying the empirical model. In the first step, an optimal control model is used to determine the optimal steady-state forest stock in Cote d’Ivoire. In the second step, an error correction model is used to analyze long run and short run relations between deforestation and agricultural productivity. Data for the empirical model were obtained from World Bank and FAO statistical database. The estimates showed that the agricultural yield responds significantly and negatively to deforestation. Indeed, a 1 per cent rise in deforestation rate will lead to about 5 per cent decline in agricultural yield. The fact that deforestation accelerates soil erosion and thus shifts agriculture to less suitable areas explains this result.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"1 1","pages":"103-111"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90080907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low multiplication ratio of yam and scarcity of planting materials are major constraints militating against sustainable yam production. In order to evaluate the behavior of the four various types of seeds of two species of yams Dioscorea cayenensis and Dioscorea rotundata, cultivated on the experimental ground of the Higher National Institute of Agronomy and Biotechnology (INSAB), a test was realized in a randomized complete block design with six replications. The samples were cut and three levels of each tuber were used: proximal, medial and distal parts of the tuber. The fragments of tuber and the whole tuber represent the various types of seed used in this work. The results showed significant (P<0.05) differences in number of plants emerged and time of emergence in a mixture of 40% soil and 60% sand three months and half after planting. For all species, the proximal parts sprouted earlier than the medium parts and then the distal parts. The fragmentation of tubers in three (3) parts can show the existence of a gradient along the tuber in its potential for sprouting and growth. There was a highly significant (P<0.05) difference between yield performances after nine (9) months of culture. This technique improves the production of tubers in both species.
{"title":"Behavior of various types of seeds of two species of yams tuber (Dioscorea cayenensis Lam. and Dioscorea rotundata Poir.) in Gabon","authors":"P. O. Ovono, C. Kevers, J. Dommes","doi":"10.14303/IRJAS.2015.025","DOIUrl":"https://doi.org/10.14303/IRJAS.2015.025","url":null,"abstract":"Low multiplication ratio of yam and scarcity of planting materials are major constraints militating against sustainable yam production. In order to evaluate the behavior of the four various types of seeds of two species of yams Dioscorea cayenensis and Dioscorea rotundata, cultivated on the experimental ground of the Higher National Institute of Agronomy and Biotechnology (INSAB), a test was realized in a randomized complete block design with six replications. The samples were cut and three levels of each tuber were used: proximal, medial and distal parts of the tuber. The fragments of tuber and the whole tuber represent the various types of seed used in this work. The results showed significant (P<0.05) differences in number of plants emerged and time of emergence in a mixture of 40% soil and 60% sand three months and half after planting. For all species, the proximal parts sprouted earlier than the medium parts and then the distal parts. The fragmentation of tubers in three (3) parts can show the existence of a gradient along the tuber in its potential for sprouting and growth. There was a highly significant (P<0.05) difference between yield performances after nine (9) months of culture. This technique improves the production of tubers in both species.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"150 1","pages":"58-66"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77435923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reduction in maize grain losses could be enhanced through identification of existing resistant genotypes and pyramiding the resistance into elite materials. This study was carried out in two trials of 100 commercial hybrids and open pollinated varieties (OPVs), and 75 landraces to identify resistant genotypes and mechanisms of resistance to Chilo partellus maize stem borers. The trials were laid out in α-lattice designs, each replicated three times during the 2010/11 and 2012 rainy seasons. Each plant was artificially infested with five C. partellus neonates three weeks after planting. Data collected included leaf toughness, stem hardness, trichome density, stem sugar content, leaf damage, number of stem borer exit holes, tunnel length and grain yield. Data were analyzed using PROC GLM of SAS 2007 package and means separated using Fishers protected least significant difference test (LSD) at (P < 0.05). Canonical discriminant analysis was performed to discriminate the mechanisms evaluated. The most resistant genotypes were CIMMYT experimental resistant hybrid checks followed by landraces and the OPVs. Top 10 resistant commercial hybrids and OPVs were PH1, PH4, DHO1, DH04, DK8031, KDVI, KDV2, PH3253, ECA-Strigoff-VL and EEQPM-8-EA, while H629, H6212, KH 600-15A, H6213 and H6210 were the most resistant commercial hybrids. Canonical discriminant analysis identified percentage stem sugar content and trichome density as the most important resistance mechanisms for discriminating the genotypes. The resistant landraces and OPVs could be utilized in breeding for maize stem borer resistance, while the resistant commercial hybrids and OPVs could be recommended for production in the relevant ecologies in Kenya to curb maize stem borer related yield losses.
{"title":"Mechanisms and levels of resistance in hybrids, open pollinated varieties and landraces to Chilo partellus maize stem borers.","authors":"Munyiri Shelmith Wanja, M. Ngure, M. Kyalo","doi":"10.14303/IRJAS.2015.029","DOIUrl":"https://doi.org/10.14303/IRJAS.2015.029","url":null,"abstract":"Reduction in maize grain losses could be enhanced through identification of existing resistant genotypes and pyramiding the resistance into elite materials. This study was carried out in two trials of 100 commercial hybrids and open pollinated varieties (OPVs), and 75 landraces to identify resistant genotypes and mechanisms of resistance to Chilo partellus maize stem borers. The trials were laid out in α-lattice designs, each replicated three times during the 2010/11 and 2012 rainy seasons. Each plant was artificially infested with five C. partellus neonates three weeks after planting. Data collected included leaf toughness, stem hardness, trichome density, stem sugar content, leaf damage, number of stem borer exit holes, tunnel length and grain yield. Data were analyzed using PROC GLM of SAS 2007 package and means separated using Fishers protected least significant difference test (LSD) at (P < 0.05). Canonical discriminant analysis was performed to discriminate the mechanisms evaluated. The most resistant genotypes were CIMMYT experimental resistant hybrid checks followed by landraces and the OPVs. Top 10 resistant commercial hybrids and OPVs were PH1, PH4, DHO1, DH04, DK8031, KDVI, KDV2, PH3253, ECA-Strigoff-VL and EEQPM-8-EA, while H629, H6212, KH 600-15A, H6213 and H6210 were the most resistant commercial hybrids. Canonical discriminant analysis identified percentage stem sugar content and trichome density as the most important resistance mechanisms for discriminating the genotypes. The resistant landraces and OPVs could be utilized in breeding for maize stem borer resistance, while the resistant commercial hybrids and OPVs could be recommended for production in the relevant ecologies in Kenya to curb maize stem borer related yield losses.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"103 1","pages":"81-90"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77159556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Woodlands in Ethiopia are under heavy pressure and shrinking overtime. Despite the woodland's economic and ecological importance's, little attention has been given to monitor the condition of the resources through time. The aim of this study is to assess the status of western dry woodlands of Ethiopia by analyzing land use and land cover (LULC) dynamics and recommend their future sustainable management and development in view of their multi-functions, climate change mitigation potentials as well as local livelihood improvement. Remote sensing (RS) and Geographic Positioning System (GIS) were used to assess the LULC dynamics in three regional states (Amhara, Tigray, and Benshangul-Gumz). Three study sites: Metema, Kafta-Humera and Sherkole were selected, respectively. In all study sites the classes of agricultural land and bare land have expanded at an average rate of 2322.9 and 726.6 ha/year, respectively. On the other hand, the woodland cover in the three districts was decreasing at an average rate of 2833.8 ha/year in the past 25 years (1985-2010). The woodland cover was transformed mainly to agriculture at an average rate of 2057.9 ha/year.
{"title":"Land use and land cover changes and associated driving forces in North Western Lowlands of Ethiopia","authors":"B. Alemu, E. Garedew, Z. Eshetu, H. Kassa","doi":"10.14303/IRJAS.2014.063","DOIUrl":"https://doi.org/10.14303/IRJAS.2014.063","url":null,"abstract":"Woodlands in Ethiopia are under heavy pressure and shrinking overtime. Despite the woodland's economic and ecological importance's, little attention has been given to monitor the condition of the resources through time. The aim of this study is to assess the status of western dry woodlands of Ethiopia by analyzing land use and land cover (LULC) dynamics and recommend their future sustainable management and development in view of their multi-functions, climate change mitigation potentials as well as local livelihood improvement. Remote sensing (RS) and Geographic Positioning System (GIS) were used to assess the LULC dynamics in three regional states (Amhara, Tigray, and Benshangul-Gumz). Three study sites: Metema, Kafta-Humera and Sherkole were selected, respectively. In all study sites the classes of agricultural land and bare land have expanded at an average rate of 2322.9 and 726.6 ha/year, respectively. On the other hand, the woodland cover in the three districts was decreasing at an average rate of 2833.8 ha/year in the past 25 years (1985-2010). The woodland cover was transformed mainly to agriculture at an average rate of 2057.9 ha/year.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"1 1","pages":"28-44"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83083256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haploid breeding via in vivo induction of maternal haploids is rapidly replacing the pedigree breeding methods since it reduces the breeding cycle from at least 6 to 1-2 generations to reach a homozygous state. Eighty doubled haploid (DH) lines derived from nine tropical maize backcross populations were crossed to two CIMMYT single cross testers (CML312/CML442 and CML395/CML444) in a North Carolina II mating design. The resultant 160 DH testcross hybrids and five commercial checks were evaluated across four well-watered locations and two drought stressed locations in Kenya using an alpha-lattice design of 15 x 11 replicated twice. Significant differences (0.05 < p < 0.001) were observed in location, genotype and genotype by environment interaction for grain yield, days to anthesis, anthesis-silking interval and ear aspect under nonstress conditions. Combined analyses across drought stress and well-watered environments showed that the top 20 hybrids performed better for grain yield and other agronomic traits of maize compared to the commercial checks. Grain yield for the top 20 DH hybrids ranged from 8.15-8.85 t/ha under optimum management and 4.53-5.67 t/ha under drought stress conditions while the best commercial variety yielded 7.67 t/ha and 3.43 t/ha under optimum and drought stress conditions, respectively. The top ten DH testcross hybrids averaged over the four optimum locations yielded 16% higher than the best commercial check while under managed drought the top ten DH hybrids produced 62% higher grain yield than the best commercial check. Three DH testcross hybrids entries 23, 28 and 71 performed highly for grain yield under both stress and non-stress locations high stress tolerance indices (STI) and low stress susceptibility indices (SSI). These results indicated that maize hybrids developed from DH lines produced as high a grain yield and as acceptable agronomic traits as the commercial hybrids developed through conventional pedigree methods. The DH lines identified in the study should be useful in improving grain yields and in the drought prone mid-altitude areas of eastern and southern Africa.
通过体内诱导母系单倍体进行单倍体育种正迅速取代纯种育种方法，因为它将育种周期从至少6代减少到1-2代，以达到纯合子状态。从9个热带玉米回交群体中获得的80个双单倍体(DH)系，采用北卡罗莱纳II型配种设计，与两个CIMMYT单交测试体(CML312/CML442和CML395/CML444)杂交。在肯尼亚四个水分充足的地区和两个干旱严重的地区，使用15 x 11的α晶格设计重复两次，对160个DH杂交测试和5个商业检查进行了评估。在非胁迫条件下，籽粒产量、花期、花丝间隔和穗向在地理位置、基因型和基因型上均存在显著差异(0.05 < p < 0.001)。在干旱胁迫和丰水环境下的综合分析表明，与商业测试相比，前20个杂交品种在玉米产量和其他农艺性状方面表现更好。最优的20个DH杂交种在最佳管理条件下的产量为8.15 ~ 8.85 t/ha，在干旱胁迫条件下的产量为4.53 ~ 5.67 t/ha，而最优的商品品种在最优和干旱胁迫条件下的产量分别为7.67 t/ha和3.43 t/ha。在4个最优位置上，前10个DH杂交组合的平均产量比最佳商业对照高出16%，而在干旱管理下，前10个DH杂交组合的产量比最佳商业对照高出62%。在胁迫和非胁迫条件下，23、28和71 3个DH试交在高抗逆性指数(STI)和低抗逆性指数(SSI)下均表现出较高的产量。这些结果表明，由DH系培育的玉米杂交种与通过传统系谱方法培育的商品杂交种具有同样高的产量和可接受的农艺性状。在这项研究中确定的DH品系在提高粮食产量和非洲东部和南部易干旱的中高海拔地区应该是有用的。
{"title":"Performance and adaptability of doubled haploid maize testcross hybrids under drought stress and non-stress conditions","authors":"O. Odiyo, K. Njoroge, G. Chemining’wa, Y. Beyene","doi":"10.14303/IRJAS.2014.055","DOIUrl":"https://doi.org/10.14303/IRJAS.2014.055","url":null,"abstract":"Haploid breeding via in vivo induction of maternal haploids is rapidly replacing the pedigree breeding methods since it reduces the breeding cycle from at least 6 to 1-2 generations to reach a homozygous state. Eighty doubled haploid (DH) lines derived from nine tropical maize backcross populations were crossed to two CIMMYT single cross testers (CML312/CML442 and CML395/CML444) in a North Carolina II mating design. The resultant 160 DH testcross hybrids and five commercial checks were evaluated across four well-watered locations and two drought stressed locations in Kenya using an alpha-lattice design of 15 x 11 replicated twice. Significant differences (0.05 < p < 0.001) were observed in location, genotype and genotype by environment interaction for grain yield, days to anthesis, anthesis-silking interval and ear aspect under nonstress conditions. Combined analyses across drought stress and well-watered environments showed that the top 20 hybrids performed better for grain yield and other agronomic traits of maize compared to the commercial checks. Grain yield for the top 20 DH hybrids ranged from 8.15-8.85 t/ha under optimum management and 4.53-5.67 t/ha under drought stress conditions while the best commercial variety yielded 7.67 t/ha and 3.43 t/ha under optimum and drought stress conditions, respectively. The top ten DH testcross hybrids averaged over the four optimum locations yielded 16% higher than the best commercial check while under managed drought the top ten DH hybrids produced 62% higher grain yield than the best commercial check. Three DH testcross hybrids entries 23, 28 and 71 performed highly for grain yield under both stress and non-stress locations high stress tolerance indices (STI) and low stress susceptibility indices (SSI). These results indicated that maize hybrids developed from DH lines produced as high a grain yield and as acceptable agronomic traits as the commercial hybrids developed through conventional pedigree methods. The DH lines identified in the study should be useful in improving grain yields and in the drought prone mid-altitude areas of eastern and southern Africa.","PeriodicalId":14478,"journal":{"name":"International Research Journal of Agricultural Science and soil Science","volume":"26 1","pages":"150-158"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82157677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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