Evaluation of physiological and morphological basis for drought resistance in maize and sorghum

Includes bibliographical references (leaves 145-171).Drought stress is often the most limiting factor to maize and sorghum production in the semi-arid areas. This study evaluates the physiological (water relations, gas exchange characteristics, membrane leakage), biochemical (antioxidant protection mechanisms and photosynthetic pigment compositions) and seed viability and quality response of maize (cv Melkassa-2) and sorghum cv Macia) after exposure to and recovery from pre and post-flowering dehydration in plants grown in a controlled environment growth chamber under constant environmental conditions (12/12h day/night, 28-32/17 °c day/night temperature, 60-80% RH and PPFD of 1200-1400 umol m-2 S-1), at the Department of Botany, University of Cape Town

Time of haricot bean intercropping into the maize- based cropping systems under conservation tillage in the rift valley of Ethiopia

Field experiments were conducted at Welenchity experimental field site, Melkassa Agricultural Research Center from June to October during the years 2010 and 2011 cropping seasons. The aim of the study was to determine optimum time of intercropping haricot bean into the maize based cropping system under conservation tillage practices, Tied-ridge and Zero-tillage. The experiment was laid out in split-plot design, with tillage practices a) Tied-ridge and b) Zero-tillage as main plot and time of intercropping haricot bean 1) Planting haricot bean simultaneously with maize, 2) Planting haricot bean 15 days after maize was planted and 3) planting haricot bean 30 days after maize was planted as sub-plots. Intercropping was assessed on the basis of the performance of the main and component crops indices as grain yield, biomass weight, partial and total LER and competitive indices such as relative crowding coefficient (K), aggressivity (A), competitive ratio (CR) and system productivity index (SPI).There was no interaction between tillage practices and time of intercropping haricot bean in any of the indices studied. Main effects of tillage practices had no significant effects on all the indices considered during both 2010 and 2011 growing seasons, but grain yield, biomass weight, partial and total LER tended to be higher in the tied-ridge treatment during 2010 and vis-versa during 2011 seasons. The results obtained showed that the greatest intercrop yields of maize and haricot bean were obtained when both crops were planted at the same time. In both years, highest total land equivalent ratio (LERt) values were obtained when planting of maize and haricot bean was done at the same time followed by planting of haricot bean 15 days after maize was planted indicating the advantages of intercropping over the sole planting. Partial LERm was always higher than LERb during 2010 season and vis-versa during 2011 season. The results of competitive indices indicate that maize was the dominant crop in the mixture as measured by the positive values of A, and the high values of Km than Kb in the mixture. On the other hand, CR values of haricot bean were higher than maize in the mixture suggesting haricot bean was more competitive than maize in the intercropping system. Moreover, the data of SPI indicated that intercropping haricot bean at the same time with maize had higher SPI during both 2010 and 2011 season. In conclusion, intercropping of haricot bean simultaneously with maize exhibited an overall advantage over the other time of intercropping and sole cropping in terms of grain yield, partial LERm, LERb and LERt and competitive ratio indices and could therefore be recommended for Central rift valley areas of Ethiopia where maize and haricot bean are major crops

Productivity and Land Use Efficiency of Wheat-Lentil Inter-cropping under Two Tillage Practices

አህፅሮት  ከጊዜ ወደ ጊዜ እየጨመረ የመጣውን ህዝብ ለመመገብ በአንድ የእርሻ ማሳ ላይ ምርታማነትን ማሳደግ በጣም አስፈለጊ ነው፡፡ ስለሆነም ሰብልን አሰባጥሮ መዝራት ምርትን ለማሳደግ ተስፋ ሰጪ ሥርዓት ተደርጎ ይወሰዳል በተጨማሪም ምርታማነትን እና የመሬት አጠቃቀምን ውጤታማ ያደርጋል፡፡ የስንዴ እና ምስር የተለያዩ የሰብል ስብጥር በስንዴ እና በምስር ምርታማነት እና የመሬት አጠቃቀም ውጤታማነት በሁለት የእርሻ አስተራረስ ዘዴ  ለመገምገም በምንጃር ወረዳ  እ.ኤ.አ. ከ 2015-2017 ባለው የሰብል ምርት ወቅት የመስክ ጥናት ተካሂዷል፡፡ ምርምሩ የተካሄደዉ እስፕሊት ፕሎት በተባለ ዲዘይን ሲሆን እያንዳንዱ ትሪትመንት ሶስት ጊዜ ተደጋግሟል፡፡ ትሪትመንቶቹ ያካተቱት ሁለት የአስተራረስ ዘዴ (ባህላዊ እና ዝቅተኛ) በዋና ፕሎት ላይ ሲዉሉ አምስት የስንዴ እና ምስር ስብጥር አዘራር ዘዴ(1፡0፤1፡1፤2፡1፤1፡2 እና 0፡1) ደግሞ በንዑስ ፕሎት ላይ በማድረግ ነዉ፡፡ የሙከራዉ ዉጤት እንዳሳየዉ በስንዴ እና ምስር የእድገት መለኪያዎች ላይ ጉልህ ተፅኖ አልነበረዉም፡፡ የአስተራረስ ዘዴዎችም በስንዴ ምርታማነት ላይ የጎላ ተፅኖ አልነበረዉም ነገር ግን በምስር ምርታማነት ላይ የጎላ ተፅኖ ነበረዉ፡፡ ከፍተኛ የምስር ምርት (1546 ኪ.ግ/ሄ.ክ) የተገኘዉ ከዝቅተኛ የአስተራረስ ዘዴ ሲነፃፀር የባሕላዊ አስተራረስ ዘዴ የተሸለ ምርት አስገኝቷል፡፡ በስብጥር አዘራር ዘዴ በሁለቱም ሰብሎች ላይ የጎላ ተፅኖ ነበረዉ፡፡ ከፍተኛ የስንዴ ምርት (2932 እና 2982 ኪ.ግ/ሄ.ር) የተገኘዉ ስንዴ ብቻውን ሲዘራ (1፡0) እና 2፡1 ስንዴ እና ምስር ስብጥር ነዉ፡፡ ይሁን እንጂ አሰባጥሮ መዝራት የምስር ምርት እንደሚቀንሰው ጥናቶ ያሳያል፡፡ ከስብጥር አዘራር ዘዴ መካከል 2፡1 ስንዴ-ምስር ስብጥር ከፍተኛ የመሬት አጠቃቀም፤የመሬትና የጊዜ አጠቃቀም እንዲሁም የገንዘብ ጥቅም አስገኝቷል፡፡ ስለሆነም 2፡1 ስንዴ-ምስር ስብጥር ለስንዴ እና ምስር በስብጥር የማምረት ዘዴ ምቹ መሆኑን ጥናቱ አረጋግጧል፡፡   Abstract To feed the ever-increasing population, increase productivity per unit area is one of the most attractive strategies. Intercropping is considered a promising system for increasing crop productivity and land-use efficiency. A field study was conducted to evaluate the effect of different crop combinations of wheat-lentil on the productivity of wheat (Triticum aestivum L.) and lentil (Lens culinaris) and land-use efficiency under two tillage practices in Minjar district during 2015-2017 cropping seasons. The experiment was carried out using split-plot design with three replications. The treatments consisted of two tillage practices (conventional and minimum tillage) assigned as the main plot and five wheat-lentil intercropping combinations (1:0, 1:1, 2:1, 1:2 and 0:1) assigned as the subplot. The tillage practices and intercropping had a significant effect on the growth parameters of wheat and lentil. Minimum tillage increased growth parameters for wheat, but reduced growth parameters for lentil. The yield of wheat was non-significantly affected by tillage practices, but the yield of lentils was significantly affected by tillage systems. A higher yield of lentil (1546 kgha-1) was obtained in conventional tillage as compared to minimum tillage practices. Intercropping combination had a significant effect on both the growth and yield parameters of both crops. The highest yield of wheat (2932 and 2982 kgha-1) was recorded in sole wheat (1:0) and 2:1 wheat-lentil combination, while the highest yield of lentil (1575 kgha-1) was obtained in sole lentil (0:1). Among intercropping combinations, 2:1 wheat-lentil gave the highest LER, ATER, and MAI values. Therefore, 2:1 wheat-lentil intercropping combinations were found suitable for higher productivity and production of component crops, and the intercropping system of wheat-lentil in any of the combinations found to be more profitable and productive compared to sole wheat and lentil

In vitro selection of sorghum (Sorghum bicolor (L) Moench) for polyethylene glycol (PEG) induced drought stress

Drought is one of the main environmental factors affecting growth and yield of sorghum in arid and semi-arid areas of the world. In vitro selection of Sorghum bicolor for drought tolerance was undertaken by the use of somaclonal variation. The experiment was carried out with a collection of sixteen sorghum genotypes and tested in a completely randomized design. Data were recorded at five different PEG 6000 (polyethylene glycol) levels (0, 0.5, 1.0, 1.5, 2.0% (w/v) treatments)) on coleoptile length (CL), root length (RL), shoot dry weight (SDW), root dry weight (RDW), root number (RN) and statistically analyzed for significant differences. Significant differences were observed among the genotypes, treatments and their interactions for the evaluated plant traits suggesting a great amount of variability for drought tolerance in sorghum. In general, embryogenic callus induction and plantlet regeneration was found to be indirectly proportional to increased PEG concentrations. By taking into consideration all the measured traits, Mann Whitney rank sum test revealed that 76T1#23 and Teshale followed by Gambella-1107 and Melkam showed better drought stress tolerance while Chelenko appeared to be drought sensitive

Analysis of Computational Science Papers from ICCS 2001-2016 using Topic Modeling and Graph Theory

This paper presents results of topic modeling and network models of topics using the International Conference on Computational Science corpus, which contains domain-specific (computational science) papers over sixteen years (a total of 5695 papers). We discuss topical structures of International Conference on Computational Science, how these topics evolve over time in response to the topicality of various problems, technologies and methods, and how all these topics relate to one another. This analysis illustrates multidisciplinary research and collaborations among scientific communities, by constructing static and dynamic networks from the topic modeling results and the keywords of authors. The results of this study give insights about the past and future trends of core discussion topics in computational science. We used the Non-negative Matrix Factorization topic modeling algorithm to discover topics and labeled and grouped results hierarchically.Comment: Accepted by International Conference on Computational Science (ICCS) 2017 which will be held in Zurich, Switzerland from June 11-June 1

Global, regional, and national cancer incidence, mortality, years of life lost, years lived with disability, and disability-Adjusted life-years for 29 cancer groups, 1990 to 2017 : A systematic analysis for the global burden of disease study

Importance: Cancer and other noncommunicable diseases (NCDs) are now widely recognized as a threat to global development. The latest United Nations high-level meeting on NCDs reaffirmed this observation and also highlighted the slow progress in meeting the 2011 Political Declaration on the Prevention and Control of Noncommunicable Diseases and the third Sustainable Development Goal. Lack of situational analyses, priority setting, and budgeting have been identified as major obstacles in achieving these goals. All of these have in common that they require information on the local cancer epidemiology. The Global Burden of Disease (GBD) study is uniquely poised to provide these crucial data. Objective: To describe cancer burden for 29 cancer groups in 195 countries from 1990 through 2017 to provide data needed for cancer control planning. Evidence Review: We used the GBD study estimation methods to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-Adjusted life-years (DALYs). Results are presented at the national level as well as by Socio-demographic Index (SDI), a composite indicator of income, educational attainment, and total fertility rate. We also analyzed the influence of the epidemiological vs the demographic transition on cancer incidence. Findings: In 2017, there were 24.5 million incident cancer cases worldwide (16.8 million without nonmelanoma skin cancer [NMSC]) and 9.6 million cancer deaths. The majority of cancer DALYs came from years of life lost (97%), and only 3% came from years lived with disability. The odds of developing cancer were the lowest in the low SDI quintile (1 in 7) and the highest in the high SDI quintile (1 in 2) for both sexes. In 2017, the most common incident cancers in men were NMSC (4.3 million incident cases); tracheal, bronchus, and lung (TBL) cancer (1.5 million incident cases); and prostate cancer (1.3 million incident cases). The most common causes of cancer deaths and DALYs for men were TBL cancer (1.3 million deaths and 28.4 million DALYs), liver cancer (572000 deaths and 15.2 million DALYs), and stomach cancer (542000 deaths and 12.2 million DALYs). For women in 2017, the most common incident cancers were NMSC (3.3 million incident cases), breast cancer (1.9 million incident cases), and colorectal cancer (819000 incident cases). The leading causes of cancer deaths and DALYs for women were breast cancer (601000 deaths and 17.4 million DALYs), TBL cancer (596000 deaths and 12.6 million DALYs), and colorectal cancer (414000 deaths and 8.3 million DALYs). Conclusions and Relevance: The national epidemiological profiles of cancer burden in the GBD study show large heterogeneities, which are a reflection of different exposures to risk factors, economic settings, lifestyles, and access to care and screening. The GBD study can be used by policy makers and other stakeholders to develop and improve national and local cancer control in order to achieve the global targets and improve equity in cancer care. © 2019 American Medical Association. All rights reserved.Peer reviewe

Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic