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Summary Common bean is an important source of dietry protein and starch in Africa and a primary staple in parts of the Great Lakes Region. Tanzania remains one of the worlds' major bean producing countries although according to official statistics, production per capita has almost halved in the last 20 years. The main international bean improvement programmes are run by the Centro Internacional de Agricultura Tropical [CIAT] from Colombia and by the Collaborative Research Support Programme [CRSP] co-ordinated by the Land Grant Universities in the USA. CIAT also maintains the world's largest collection of Phaseolus germplasm. The National Bean Programme in Tanzania is supported by both CIAT and CRSP. Collaboration between these international programmes and the National Programme has resulted in the release of more than 20 improved bean varieties. The paper reviews the development of bean improvement programmes in Tanzania since 1959, the contribution made by the international programmes and the strategies used to develop high-yielding bean varieties with resistance to pests and diseases and tolerance to some edaphic stress factors.  相似文献   
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Chemical assays demonstrated that rye and barley cultivars contained relatively high levels of trypsin inhibitor activity as compared to oat and wheat cultivars, and there was a low degree of stability to prolonged wet heat treatment. In feeding trials with broiler chicks, incorporation of 67% raw barley or 50% raw rye in the rations enhanced feed intake and weight gains, and the marginal increases in pancreas weight were not reversed by feeding autoclaved cereals. Raw rye cultivars fed at the 75% level in mouse diets reduced weight gains, feed efficiency, protein digestibility, protein efficiency ratio and biological value. Autoclaving to inactivate trypsin inhibitors, or ether extraction to remove the resorcinols, failed to improve the nutritive value of rye diets for mice. It appeared that the protease inhibitors in the four cereals were relatively weak inhibitors of trypsin in the digestive system despite stability to dry heat and acid pH.  相似文献   
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A study was carried out on the lactation performance of crossbred dairy cattle in a smallholder farming system in north-east Tanzania. Data were collected from the records for 6 years and the factors considered were district, proportion of Holsteins, season of calving, year of calving and herd size. The data were considered separately for animals with a single lactation record. The least-square means for first lactation length and yield were 331 days (SD 77.0) and 2332 L (SD 283.0), respectively, while for cows with data on more than one lactation record the yield was 2477 L (SD 840.1) in 324 days (SD 74.0). First lactation yield was significantly affected by year of calving. For repeated records the lactation yield was significantly affected by district, proportion of Holsteins and herd size, while lactation length was significantly affected by district and herd size. The calculated repeatabilities for lactation yield and length were 0.27 and 0.12, respectively. For the pooled data the correlation between lactation length and yield gave r = 0.569 (p<0.0001).  相似文献   
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Pigeonpea is one of the major legume crops grown in eastern Africa but has been relatively neglected in terms of research and development. The peas are a rich source of protein and the crop is nitrogen-fixing and drought tolerant. It is an ideal crop for the semi-arid areas of Africa and there is great potential for it to be more widely grown. The large number of pests and diseases which attack pigeonpea in Africa (and elsewhere) is perhaps the main constraint to increased production. The most important pest worldwide is the pod borer, Helicoverpa armigera, but the flowers and pods are attractive to a wide range of insect pests. The most important disease in eastern Africa is Fusarium wilt (Fusarium udum) and considerable effort has been devoted by ICRISAT to developing wilt-resistant pigeonpeas, adapted to cultivation in the region. This paper reviews the literature on pests and diseases of pigeonpea with special reference to eastern Africa and presents some new information on distribution and damage levels for the key pests and diseases.  相似文献   
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