首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到4条相似文献,搜索用时 46 毫秒
1.
海南荔枝种质资源果实主要性状多样性分析   总被引:1,自引:0,他引:1  
对中国热带农业科学院热带作物品种资源研究所、海南省农业科学院热带果树研究所种质圃的荔枝品种(种质)和海南的霸王岭、尖峰岭等地采集的野生荔枝果实的主要性状进行了鉴定评价。结果表明:海南荔枝品种(种质)的果实形状、果实大小、果皮龟裂片、果皮颜色、果实可食率、可溶性固形物、可滴定酸、维生素C含量等方面均存在丰富的遗传多样性。  相似文献   

2.
The objective was to compare alternative models for fitting to data on degradation of dry matter (DM), organic matter (OM) and crude protein (CP) in the rumen of two harvests of four temperate grasses, made into hay in Belgium, and one harvest of three tropical grasses commonly used in Burundi. Fifteen non-linear models were used and these included generalized Mitscherlich, simple Mitscherlich (or exponential), generalized Michaelis–Menten, Gompertz, logistic, simple Michaelis–Menten, segmented Van Milgen and von Bertalanffy models. Degradation profiles of DM, OM and CP obtained in sacco from the rumen of three mature sheep were fitted to all the models. The convergence success rate along with acceptable parameters was used as a first tool to eliminate models. Comparisons between the remaining twelve models were then made using the run test of sign, the root mean square prediction error, the root mean square error, the lack of fit test and the variance ratio test criteria. On the basis of an overall assessment using these tests, the Gompertz lagged model was the best suited to fit the degradation data of both temperate and tropical grasses. This study confirmed the superiority of sigmoid type functions over diminishing return-type models.  相似文献   

3.
ABSTRACT

Shea tree (Vitellaria paradoxa) is one of the main native oil plants with high economic value in Africa. Its fruits are used for food, medicinal, cultural and exportation purposes. However, the lack of efficient tools to assess annual fruit production of the species limits the sustainable management of its resources. Therefore, production statistics are useful to organize the activities of the shea sector. This study aimed to (i) assess the interannual variation in fruit production along a climatic gradient in Burkina Faso, (ii) examine fruit production patterns according to climatic zones and tree size, (iii) assess the contribution of high-yielding trees in the annual potential production and (iv) develop allometric equations for estimating fruit yields of the species. The yield of 212 trees distributed across three climatic zones was monitored over four successive years. Within each climatic zone, fruit production was significantly different among years. Fruit production was positively and significantly correlated with tree size. The interannual variation in fruit production at tree individual level was higher in drier climatic conditions. The mean interindividual synchrony was less than 50% in each zone, suggesting a large range in fruit production patterns of the species. Annually, more than 55% of the total fruit production was supported by high-yielding trees. The best regression models for estimating fruit yields had R 2 values of 69–73% with prediction errors ranging from ?7% to 4%. Our findings are useful tools for the planning of rational exploitation of shea tree’s resources and its sustainable management.  相似文献   

4.
Taiwan is a small island located in monsoon Asia with an annual precipitation exceeding 2,500 mm, which is 2.6 times the world average. However, water available for each person in Taiwan is less than one seventh of the world average due to Taiwan's crowded population and river basin characteristics. Steep land slope and uneven time and space distribution of rainfall have caused water resources problems. Providing a pure and plentiful supply of water for the people challenges the Water Resources Agency in Taiwan. History is a powerful tool for portraying the future. This paper discusses major themes in the review of water resources development over the last centuries. The changes in social-economic development, water resources infrastructure and demands of water are central to the discussion, with an eye to the plentiful and sustainable implications of water resources management in Taiwan. The water policy in the twenty-first century is also outlined.Dr. Hwang is the Advice of the Council for Economic Planning and Development (CEPD), Ministry of Economic Affairs (MOEA), Taiwan, Chairman of the Water Resources Committee, Chinese Institute of Civil and Hydraulic Engineering, a board member of the International Commission on Irrigation and Drainage (ICID) Chinese Taipei Committee, former chairman of the Chinese Society of Agriculture Engineering (CSAE), former director of Water Resources Agency (WRA), former director of the Taiwan Provincial Water Conservancy Agency (TPWCA), and former director of the Taiwan Provincial Water Conservancy Bureau (TPWCB).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号