Genetic variation in survival,growth, and stem form of Pinus leiophylla in Brazil and South Africa and provenance resistance to pitch canker

Pinus leiophylla is a relatively common pine that occurs in the mountains of western and central Mexico. Between 1987 and 1990, Camcore, North Carolina State University, sampled 11 populations and 309 mother trees of the species to determine patterns of genetic variation in survival, growth and stem form. Fifteen provenance/progeny trials were established in southern Brazil and South Africa across a wide range of sites and assessed at 3, 5 and 8 years of age for height, diameter and stem form. Results indicated that average productivity ranged from 5 to 19m³ ha^?1 y^?1 depending on the site and that performance was not as competitive as P. patula (South Africa) and P. taeda (Brazil) controls. Provenances from central Mexico (Michoacán) were statistically better in productivity than those from the southern part of the country (Oaxaca), which in turn were superior to those from the northern part of the country (Durango). However, provenances from northern Mexico exhibited superior survival to seed sources from other locations in Mexico when grown on cold sites (winter minimums –10 to 5°C) in South Africa and superior stem form across all locations. Seedlings from the original 11 provenances were screened for resistance to the pitch canker fungus (PCF; Fusarium circinatum). Results indicated that generally P. leiophylla is as susceptible to PCF as P. patula (stemkill = 85%) with the exception of two fast-growing, moderately resistant populations from Michoacán, La Pinalosa (stemkill = 44%) and Ario de Rosales (stemkill = 73%). The future potential of P. leiophylla might be in hybrid combination with P. patula in the seasonally dry areas of southern Africa where fires are common and pitch canker is a problem.     

蕹菜人工种子—腋芽的包裹,萌发及贮藏研究

本文以蕹菜(Ipomoea aquatica Forsk.)小叶品种为材料,用由MS基本培养基配制的2—5％海藻酸钠包裹腋芽节段(固化剂为2—5％CaC12),制作人工种子。人工种子在MS琼脂培养基上的萌发率达51.02％,在营养土中成苗率为27.59％,大田移栽成活率达100％。低温(4±1)贮藏30天和60天后,萌发率分别为42和26％。     

西洋杜鹃组织培养技术体系研究(Ⅰ)——基本培养基和外植体的选择

实验以不同季节的茎尖 (含茎段 )为材料 ,采用不同基本培养基 ,研究确定西洋杜鹃组织培养适合的基本培养基类型 ,植株再生的可能途径 ,以及适宜的培养条件。结果表明 :①低盐分浓度及高比值NH4 +/NO3 -的基本培养基Read培养基适合西洋杜鹃 ;②最适外植体为摘花芽后萌发的顶芽茎尖 ;③最佳取材时间为 3～ 5月 ;④培养条件 :温度 2 5± 2℃ ,光照 16h/黑暗 8h ,光照强度 15 0 0～ 2 5 0 0lx。     

观赏植物快繁技术研究概况

植物组织培养技术是实现观赏植物规模化、现代化生产的重要途径。快速繁殖技术和脱毒苗培育技术是植物组织培养应用最广泛和最有成效的 2个领域。本文就这两领域的研究现状和应用概况进行了综述 ,并提出了这两项技术实现工厂化生产应研究的主要目标     

西洋杜鹃组织培养技术体系研究(Ⅱ)——培养物的增殖和生根

研究西洋杜鹃茎尖再生植株无菌培养物建立、初代培养、继代培养和生根培养 4个技术环节 ,最终建立西洋杜鹃组培快速繁殖技术体系。试验结果按最佳处理计算 ,一个外植体年理论增殖系数可达到 2 6× 10 5。植物组培快繁技术是解决西洋杜鹃种苗缺乏的有效途径     

布鲁拉美利奴主效基因在绵羊育种中的应用

布鲁拉美利奴主效基因是在绵羊中发现的多羔基因，对绵羊的育种具有重要的意义。本文对该主效基因的发现过程、效应及作用机理、应用现状和前景作一综述，以供国内同类研究借鉴