发布求助
文献互助 智能选刊 最新文献

Tropical Science最新文献

筛选
英文 中文
Genetic improvement of the Kenya Dual Purpose goat: Influence of economic values and prospects for a practical breeding programme 肯尼亚双重用途山羊的遗传改良:经济价值的影响和实际育种计划的前景
Tropical Science Pub Date : 2007-09-01 DOI: 10.1002/TS.204
R. Bett, I. Kosgey, B. Bebe, A. Kahi
{"title":"Genetic improvement of the Kenya Dual Purpose goat: Influence of economic values and prospects for a practical breeding programme","authors":"R. Bett, I. Kosgey, B. Bebe, A. Kahi","doi":"10.1002/TS.204","DOIUrl":"https://doi.org/10.1002/TS.204","url":null,"abstract":"This study determined the influence of economic values on genetic gain and explored the prospects for a practical breeding programme for the Kenya Dual Purpose Goat. The economic values for production traits (live weight (direct), live eight (maternal), milk yield and consumable meat) and functional traits (doe weight, number of kids weaned, kidding frequency and rate, doe weaning and survival rate, pre- and post-weaning survival rate, and residual feed intake for yearlings and does) in the breeding goal addressed the smallholder production system. There was a potential for genetic progress in the breeding-goal traits even by using simple selection criteria. In the breeding programme, the predicted genetic gains per year for milk yield were 0.737 and 0.047 kg for the sires of sires and dams of dams pathways, respectively. The required population size of 2500 does in the nucleus would be attained within ten years after the start of the breeding programme. The availability of a simple breeding programme for the Kenya Dual Purpose Goat offers enormous opportunities for private large-scale flocks or for flocks owned by parastatal or research organisations to exploit genetic and economic benefits from the breeding programme. Copyright © 2007 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82526429","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}
引用次数: 15
Spatial and temporal aspects of agricultural sustainability in the semi‐arid tropics: a case study in Mbeere district, Eastern Kenya 半干旱热带地区农业可持续性的时空方面:肯尼亚东部Mbeere地区的案例研究
Tropical Science Pub Date : 2007-09-01 DOI: 10.1002/TS.207
D. Onduru, C. C. Preez
{"title":"Spatial and temporal aspects of agricultural sustainability in the semi‐arid tropics: a case study in Mbeere district, Eastern Kenya","authors":"D. Onduru, C. C. Preez","doi":"10.1002/TS.207","DOIUrl":"https://doi.org/10.1002/TS.207","url":null,"abstract":"A study was conducted in the semi-arid Mbeere district, Eastern Kenya, to determine spatial and temporal variability of crop yields and climatic factors and their impacts on sustainability of semi-arid agriculture. Spatial aspects were assessed by conducting a survey of on-farm crop yields and using a computer model (QUEFTS) to predict maize yields from soil chemical indices. Temporal aspects were studied using time-series data (rainfall, temperature and crop yields). The study did not find a significant correlation between farmers' actual yields and QUEFTS predictions, and soil nutrients were thus not the only factors influencing maize yields in the study area. Other yield-reducing factors (climate and management) not accounted for in the QUEFTS model played a role. Grain yields of staple food crops were highly variable, fluctuating in time and space, and suboptimal. Particular aspects of rainfall (e.g. the short rains, for cowpeas and beans) were more important than mean annual rainfall in determining crop yields, and factors other than rainfall and soil fertility apparently played a role. The observed low grain yields, large yield gaps and high rainfall variability challenge the sustainability of these farming systems. Copyright © 2008 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82922048","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}
引用次数: 14
Milk production and reproductive performance of Sahiwal cattle in semi‐arid Kenya 肯尼亚半干旱地区Sahiwal牛的产奶量和繁殖性能
Tropical Science Pub Date : 2007-09-01 DOI: 10.1002/TS.205
E. Ilatsia, T. Muasya, W. B. Muhuyi, A. Kahi
{"title":"Milk production and reproductive performance of Sahiwal cattle in semi‐arid Kenya","authors":"E. Ilatsia, T. Muasya, W. B. Muhuyi, A. Kahi","doi":"10.1002/TS.205","DOIUrl":"https://doi.org/10.1002/TS.205","url":null,"abstract":"The aim of this study was to evaluate milk production and reproductive performance of Sahiwal cattle in semi-arid Kenya. Milk production traits considered were lactation milk yield, lactation length and test-day milk yield, while reproductive traits included age at first calving, calving interval and number of services per conception. Various fixed effects affected performance of milk production and reproductive traits to varying significance levels. The mean estimates for milk production traits were 1368 kg, 282 days and 4.9 kg for lactation milk yield, lactation length and test-day milk yield, respectively. For reproductive traits, mean estimates were 468 days, 2.2 and 1345 days for calving interval, number of services per conception and age at first calving, respectively. There was a decline in lactation milk yield and lactation length, and an increase in calving interval and age at first calving over the years. Satisfactory management and appropriate genetic improvement strategies would result in improved performance. Implications of the results for genetic improvement of the breed in Kenya are discussed. Copyright © 2007 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72662305","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}
引用次数: 16
Inheritance of resistance in cowpea (Vigna unguiculata) to the pod‐sucking bug Clavigralla tomentosicollis (Hemiptera: Coreidae) 豇豆(Vigna unguiculata)对吸豆荚虫(半翅目:绒蚧科)抗性的遗传
Tropical Science Pub Date : 2007-09-01 DOI: 10.1002/TS.206
G. Olatunde, Ia Biobaku, D. Ojo, O. Pitan, E. Adegbite
{"title":"Inheritance of resistance in cowpea (Vigna unguiculata) to the pod‐sucking bug Clavigralla tomentosicollis (Hemiptera: Coreidae)","authors":"G. Olatunde, Ia Biobaku, D. Ojo, O. Pitan, E. Adegbite","doi":"10.1002/TS.206","DOIUrl":"https://doi.org/10.1002/TS.206","url":null,"abstract":"Inheritance of resistance in cowpea to Clavigralla tomentosicollis Stal was studied on F1, F2 and F3 generations produced from crosses made between Ife Brown, a susceptible cultivar (PS), and TVu 3354, a resistant variety (PR), on the pods of which freshly emerged nymphs of C. tomentosicollis were caged. Nymphal weight gain was significantly higher (p < 0.05) on PS. There were no significant differences between the weight gains of nymphs that fed on F1, F2 and F3 pods. Insect mortality was significantly higher on PR (86.7%) and the F2 (70.0%) generation. Total nymphal development period was significantly longer on PR (15.0 days) while that on F1 and F2 generations was significantly longer than on the F3 generation. Nymphal survival and adult emergence were observed on eight plants out of 60 and 19 plants out of 80 from the F2 and F3 generations, respectively. Broad-sense heritability estimates were 90.3% and 94.3% for the F2 and F3 generations, respectively. The results clearly indicated that TVu 3354 has highly heritable resistance to C. tomentosicollis. Copyright © 2008 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90586952","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}
引用次数: 5
Gross anatomy and characteristics of the reproductive system of the land snail Archachatina marginata ovum (Pfeiffer) during the breeding season 繁殖季节地螺卵的大体解剖及生殖系统特征
Tropical Science Pub Date : 2007-06-01 DOI: 10.1002/TS.197
R. Egonmwan
{"title":"Gross anatomy and characteristics of the reproductive system of the land snail Archachatina marginata ovum (Pfeiffer) during the breeding season","authors":"R. Egonmwan","doi":"10.1002/TS.197","DOIUrl":"https://doi.org/10.1002/TS.197","url":null,"abstract":"The changes that occurred in the reproductive system during the breeding season of the land snail Archachatina marginata ovum (Pfeiffer) were investigated from April to July 2005 in collections obtained from snail hunters. These changes were divided into four stages (juvenile stage, mating readiness, egg production and post reproductive), which are described. The observations on the changes in the reproductive organs of A. marginata ovum suggest that the adult population is vulnerable during the breeding season. Management guidelines that will enhance commercial production of the snails are discussed. Copyright © 2007 John Wiley & Sons, Ltd.","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85216358","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}
引用次数: 2
Marketing margin and determinants of net returns of beef marketing in southeast Nigeria 尼日利亚东南部牛肉市场营销利润和净收益的决定因素
Tropical Science Pub Date : 2007-06-01 DOI: 10.1002/TS.201
C. Eze
{"title":"Marketing margin and determinants of net returns of beef marketing in southeast Nigeria","authors":"C. Eze","doi":"10.1002/TS.201","DOIUrl":"https://doi.org/10.1002/TS.201","url":null,"abstract":"This study examined: the marketing costs, margins and returns of retailed beef meat in southeast Nigeria; factors influencing the traders' net returns; problems associated with marketing of beef; and the socio-economic characteristics of respondent traders. Sixty respondents were selected at random, with 20 respondents from each of three purposively selected markets in the study area. A structured interview schedule and personal observations were sources of primary data. The field data were analysed using cost-return principles, multiple regression analysis and descriptive statistics. The gross margin for trading was \u0000 \u0000 \u0000 \u00009,790 (=US$81.58) per 250 kg dressed meat, with a net return of \u0000 \u0000 \u0000 \u00008,605 (=US$71.71) and an average sales receipt of \u0000 \u0000 \u0000 \u000078,400 (= US$653.33). The cost of meat, transport costs, other costs (garage fees, storage, taxes), experience in the trade and level of education significantly (p < 0.05) affected the traders' net returns. Insufficient capital, inadequate stock supply, high transport cost and storage were identified as the major problems associated with meat trading in the study area. Copyright © 2007 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75125995","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}
引用次数: 4
Survival and transmission of Colletotrichum lindemuthianum from naturally infected common bean seeds to the seedlings 普通豆自然侵染后炭疽病菌的存活及向幼苗的传播
Tropical Science Pub Date : 2007-06-01 DOI: 10.1002/TS.202
M. Yesuf, S. Sangchote
{"title":"Survival and transmission of Colletotrichum lindemuthianum from naturally infected common bean seeds to the seedlings","authors":"M. Yesuf, S. Sangchote","doi":"10.1002/TS.202","DOIUrl":"https://doi.org/10.1002/TS.202","url":null,"abstract":"Surveys were made of major seed-borne fungi associated with seeds of common bean (Phaseolus vulgaris L) in different bean-growing areas of Ethiopia. Field and laboratory experiments were also carried out during the 2003 and 2004 crop seasons to study the survival and transmission of bean anthracnose pathogen Colletotrichum lindemuthianum to the seedlings. The major seed-borne fungi associated with common bean seeds were Colletotrichum lindemuthianum, Phaeoisariopsis griseola and Ascochyta phaseolorum. Bean anthracnose survived in infected seeds but not in the soil, and the primary source of bean anthracnose infection in the field was from infected seeds. Seed infection of common beans by bean anthracnose resulted in both pre-emergence and post-emergence mortality of bean seedlings. A significant positive relationship was found between the levels of primary seed infection and seedling infection in the field. Further development of bean anthracnose in the field was influenced by weather variables (rainfall, number of rainy days, humidity and temperature). Copyright © 2007 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89780168","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}
引用次数: 24
Clonal propagation in cashew (Anacardium occidentale): effect of rooting media on the rootability and sprouting of air-layers 腰果(Anacardium occidentale)无性系繁殖:生根介质对空气层生根性和发芽的影响
Tropical Science Pub Date : 2007-06-01 DOI: 10.1002/TS.198
O. Aliyu
{"title":"Clonal propagation in cashew (Anacardium occidentale): effect of rooting media on the rootability and sprouting of air-layers","authors":"O. Aliyu","doi":"10.1002/TS.198","DOIUrl":"https://doi.org/10.1002/TS.198","url":null,"abstract":"An evaluation of three different rooting media (topsoil, sawdust and river sand) mixed in different proportions for the rooting of cashew layers was carried out at the Cocoa Research Institute of Nigeria at Ibadan, southwestern Nigeria. Data were collected on percentage take, number of days to rooting, number of roots, root length and percentage sprouting, and were statistically analysed. Significant differences were recorded for the effects of medium, mixture proportion, genotype and medium × mixture proportion interaction, showing the strong influence of the rooting medium (and thus its composition – texture, nutrient status and water-holding capacity) and the variation in genotypic response to rooting in cashew layers. Topsoil ranked best among the three media tested, and its combination with either sawdust or river sand in the ratio 1 : 1 (v/v) gave the best rooting and sprouting, thus suggesting its use as an effective rooting medium for cashew layering. Copyright © 2007 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87238575","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}
引用次数: 10
Changes in nutritional properties of yam (Dioscorea spp.), plantain (Musa spp.) and cassava (Manihot esculenta) during storage 山药(Dioscorea spp.)、车前草(Musa spp.)和木薯(Manihot esculenta .)贮藏期间营养特性的变化
Tropical Science Pub Date : 2007-06-01 DOI: 10.1002/TS.200
D. Sahoré, G. Nemlin, A. Kamenan
{"title":"Changes in nutritional properties of yam (Dioscorea spp.), plantain (Musa spp.) and cassava (Manihot esculenta) during storage","authors":"D. Sahoré, G. Nemlin, A. Kamenan","doi":"10.1002/TS.200","DOIUrl":"https://doi.org/10.1002/TS.200","url":null,"abstract":"White cassava roots (bitter variety), plantain stems (‘Afoto’ variety) and yam tubers (Dioscorea alata ‘Florido’) were stored for 28 days after harvest in the laboratory in ambient conditions (28°C). The changes in their nutritional properties (moisture, acidity, protein, lipid, carbohydrate, total sugar, ash and calorific value) were studied after different periods of storage. The nutritional changes of the three commodities were described and compared. Cassava and green plantain could be kept for a week without significant deterioration but showed progressive deterioration thereafter, while yam tubers underwent only slight changes over the total 4-week storage period. Copyright © 2007 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84474957","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}
引用次数: 25
Dimensions of food insecurity and livelihood strategies among rural households in Dire Dawa, eastern Ethiopia 埃塞俄比亚东部迪勒达瓦农村家庭粮食不安全的维度和生计战略
Tropical Science Pub Date : 2007-06-01 DOI: 10.1002/TS.199
A. Shimelis, A. Bogale
{"title":"Dimensions of food insecurity and livelihood strategies among rural households in Dire Dawa, eastern Ethiopia","authors":"A. Shimelis, A. Bogale","doi":"10.1002/TS.199","DOIUrl":"https://doi.org/10.1002/TS.199","url":null,"abstract":"Based on household-level data gathered from 115 randomly selected rural locations in Dire Dawa, the extent of food security and livelihoods strategies was scrutinised. Food insecurity was found to be a severe problem in the area with 76% of the households being food insecure, and with a food-insecurity gap and severity of food insecurity of 31% and 15%, respectively. The study also identified various livelihood strategies of the rural households, which were found to be a composite of different activities to enable them to make a living. These activities included mixed crop-livestock farming, diversification of crop production, diversification of livestock production, and supplementation of crop and livestock production with off-farm activities. Copyright © 2007 John Wiley & Sons, Ltd","PeriodicalId":23388,"journal":{"name":"Tropical Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75961814","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}
引用次数: 18
首页 上一页 下一页 尾页
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整，为了账户安全，请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们：info@booksci.cn Book学术提供免费学术资源搜索服务，方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号：481959085
Book学术官方微信