Land-races of wheat from the northern Negev in Israel

Summary Wheat has traditionally been grown by the Beduin population in the semi-arid (150 to 200 mm, mean total annual rainfall) northern Negev region of Israel.A collection was made in this area (the size of which is 150 km²) from small (0.1 to 0.5ha) fields of mixed wheat, resulting in 1553 collected spikes. Each spike was planted in a 1 m row at Bet Dagan, and grown under favorable conditions. Qualitative and quantitative data were collected from each row. Qualitative data were submitted to hierarchial clustering and the results were compared with published information on the identification, classification and distribution of the land-races of wheat in the Middle East. Triticum durum was represented in 84% of the collection. It was clustered into 22 populations, identified as 11 known varietas of T. durum. They were aggregated into five groups, similar to groups of old varieties recognized by Jacubziner (1932). While 38.5% of the collection consisted of T. durum groups villosa and sinaica, aboriginal to the northern Negev, it included also forms similar to several land-races found in the past in other parts of the Middle East. Each of the populations, and the durum collection as a whole, was very diverse for the quantitatively measured plant attributes. Triticum aestivum was represented in 15.6% of the collection, clustered into six populations. Most of the common wheat accessions were analogous to the old locally grown variety Hirbawi. Triticum compactum was represented in only eight accessions.The collection is now being evaluated as a potential genetic resource for durum wheat breeding.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel No. 374-E, 1982 series.     

Genome-wide association mapping focusing on a rice population derived from rice breeding programs in a region

Plant breeding programs in local regions may generate genetic variations that are desirable to local populations and shape adaptability during the establishment of local populations. To elucidate genetic bases for this process, we proposed a new approach for identifying the genetic bases for the traits improved during rice breeding programs; association mapping focusing on a local population. In the present study, we performed association mapping focusing on a local rice population, consisting of 63 varieties, in Hokkaido, the northernmost region of Japan and one of the northern limits of rice cultivation worldwide. Six and seventeen QTLs were identified for heading date and low temperature germinability, respectively. Of these, 13 were novel QTLs in this population and 10 corresponded to the QTLs previously reported based on QTL mapping. The identification of QTLs for traits in local populations including elite varieties may lead to a better understanding of the genetic bases of elite traits. This is of direct relevance for plant breeding programs in local regions.     

新形势下民族地区学校管理现状及其对策

学校管理是根据一定的教学目标,通过决策、计划、组织、指导和控制,有效地利用学校的各种要素来培育人的活动。民族地区的学校有许多特点,传统的学校管理存在许多弊端,新形势下的民族地区学校管理必须转变观念和思想,以人本思想为主,注重团队合作,创新管理,依法管理,实现新课程所确定的目标。     

大学“农民工”子女的现状与学习动机分析

大学农民工子女的现状不容乐观,这既是当前高等教育深层次改革中遇到的新的理论问题,又是新的实践问题,积极探索其解决的办法,对促进社会和谐,培养德智体全面发展的人具有积极的意义。     

CELⅠ酶的粗纯化及活性分析

TILLING（Targeting-induced local lesions in genomes）技术作为反向遗传学的一个重要研究工具，目前在众多的模式生物分子生物中得到广泛应用，其中CELⅠ酶是TILLING技术的核心。本实验通过硫酸铵沉淀、亲合层析、阴阳离子交换柱层析等常规的蛋白质纯化过程，从芹菜中粗纯化了具有较高活性的稳定的CELⅠ酶。并以杂合双链DNA为底物，对不同纯化程度的CELⅠ酶以及在不同温度、处理时间、有无Taq DNA多聚合酶的条件下进行了CELⅠ酶的错配切割活性分析。结果发现，所获得的CELⅠ酶得到了一定的纯化；CELⅠ酶的反应最适温度范围为40℃～50℃；长时间酶切特异性好；在含有Taq酶的酶切体系中，CELⅠ酶错配切割效果更佳，这与已报道的实验结果基本一致。与其他单位提供的CELⅠ酶活性相比，本实验分离纯化的CELⅠ酶活性值略高。通过对CELⅠ酶的提取及活性分析，为TILLING技术大规模和低成本的应用于家蚕功能基因组研究提供了保障。     

局部供应硝酸盐诱导玉米侧根生长的基因型差异

以两个玉米(Zea.mays.L.)自交系478和Wu312为研究材料,采用琼脂培养方法,研究局部供应不同浓度的硝酸盐(NO3-)对侧根生长的影响。结果表明,根系局部供应0.5mmol/L硝酸盐,可以促进两个基因型相应部位的侧根长度,对478的促进效果显著高于Wu312。在双层局部供应0.5mmol/L硝酸盐时,能够刺激两个层次478局部侧根伸长,而Wu312只在上层表现出促进作用。多浓度试验结果表明,在0.5～25mmol/L范围内,局部供应硝酸盐均能在478上表现促进效果。而在Wu312上,当局部硝酸盐浓度超过5mmol/L,刺激作用消失。在低浓度范围内,局部供氮不影响侧根。当局部供应的硝酸盐浓度超过5mmol/L时,Wu312的侧根数量急剧下降,超过15mmol/L后,478的侧根数量开始下降。478侧根对局部硝酸盐刺激的响应能力显著高于Wu312。     

长武王东沟试验区因地制宜发展沟坡苹果园成效显著

长武县由于人多耕地少，沟坡多塬面少，扩大塬面苹果栽埴面积，加剧了与粮食，烤烟生产争地的矛盾。王东沟试验区提出栽植沟坡果园优于塬面果园的规划，并取得比塬面高效的成功经验，应因地制宜加以推广。     

Increasing the relevance of scientific information in hillside environments through understanding of local soil management in a small watershed of the Colombian Andes

Abstract. This article explores the question of how scientific information can improve local agronomic management using concepts of uncertainty classification and uncertainty management. Information and data on local management of soil fertility based on a local classification system of soil quality were collected from a small watershed in Cauca (Colombia). The analyses suggest that farmers hold local knowledge about soils at two levels. The first is based on empirical observations and refers to local knowledge about soils and landscape, which shows that the classes identified in the local soil quality classification are consistent with results obtained using measured soil parameters. At the second level, farmers have some awareness of ecological processes and the appropriate use of relationships between key soil characteristics and management options. It is argued that local knowledge is not sufficient to cope with uncertainty introduced by a rapidly changing agriculture, including, for example, increasing land pressure, unpredictable market forces and climate change. We have suggested how scientific knowledge can contribute to the solution, based on an analysis that relates Cohen's ( Heuristic reasoning about uncertainty: an artificial intelligence approach . Pitman London, 1985) and Rowe's ( Risk Analysis 14, 743–750, 1994) uncertainty concepts to local knowledge.     

金沙江干热河谷植被恢复研究进展

植被恢复是金沙江干热河谷区生态恢复的有效途径。分析了金沙江干热河谷特殊的自然条件和恶劣的生态环境现状，回顾了金沙江干热河谷自1950年代以来的植被恢复历程，综述了金沙江干热河谷植被恢复中的理论研究、品种选择、技术突破、效益评价等的研究进展，指出了目前本区植被恢复中研究手段、方法和内容等方面的不足，强调今后研究应注重加强高新技术的应用，重视植被恢复的科学性、现实性和可操作性，及加大乡土种的筛选与应用研究等方面的内容。