太湖流域糯稻地方品种资源农艺性状分析

为了充分利用地方资源有利基因拓展现代育成品种的遗传基础和改良目标性状,本研究利用15个主要农艺性状对135个太湖流域糯稻地方品种资源进行了分析。结果表明,晚熟、株高和穗颈长偏高、着粒密度和产量偏低为太湖流域糯稻地方品种的主要特征。性状的变异系数范围为3.42%~35.01%,单株产量、单株有效穗、每穗总粒数、每穗实粒数、穗颈长短、着粒密度等6个性状居前列。主成分分析显示,PC1-PC5能够解释总体70.4%的变异,而每穗总粒数、每穗实粒数、着粒密度、单株有效穗、株高、千粒重、单株产量等7个性状因具有高的特征向量值,为分析太湖流域糯稻地方品种资源的重要性状。以主成分分析中提取的5个公因子进行聚类分析,可将研究材料分为14类,其中第Ⅰ、Ⅸ、ⅩⅣ和Ⅻ类品种有利性状突出,是改良当地糯稻品种的极有用的种质资源。产量构成因子和单株产量的偏相关分析表明,太湖流域糯稻地方品种对产量的贡献主要是单株有效穗和每穗粒数,这也是地方品种亟待改良的重点。研究还发现,同名异种现象十分普遍。     

Drought response of pearl millet landrace-based populations and their crosses with elite composites

Drought is the primary constraint in pearl millet (Pennisetum glaucum) production in the drier semi-arid and arid regions of south Asia and Africa. The traditional landraces from drier regions are good sources of drought adaptation but often lack high yield under near-optimum growing environments. The objective of this paper was to assess whether crosses between landrace populations and elite germplasm can produce hybrids with better grain yield under favourable conditions than landraces, without compromising grain yield under drought. The research evaluated 20 crosses and their nine parents (consisting of landrace-based populations and elite composites) under drought and non-drought conditions. Drought response index (DRI), based on flowering and grain yield measured in drought and non-drought environments, was used to assess drought tolerance. Landrace populations yielded significantly more grain under drought stress than elite composites and crosses and had the highest mean DRI (3.99). In contrast, composites showed maximum sensitivity to drought with significantly negative DRI (−3.64). Adaptation to either drought or high productivity conditions appeared to be associated with different plant types: higher panicle number, lower grain number per panicle, and smaller seed size were associated with drought adaptation; low tillering and greater number of large-sized seeds per panicle were favoured for optimum growing conditions. Crosses yielded significantly better than composites under drought, better than landrace populations under non-drought and had a wide range in drought sensitivity. Around 40% of crosses produced on average 23% higher grain yield than the best landrace under favourable conditions, without compromising grain yield under drought. The results illustrate that hybridization of landrace populations with elite composites can produce germplasm that combines drought tolerance of traditional material with high production potential of elite genetic material.     

甘肃豌豆地方品种资源白粉病抗性鉴定

以从甘肃定西、临夏、河西等地收集的34份豌豆地方品种资源为试材,在田间自然感病条件下,结合室内盆栽人工接种试验,进行豌豆白粉病抗性鉴定。结果鉴定出抗病资源7份,占全部鉴定材料的20.59%,其中 D27表现为抗病（R）,占供试材料的2.94%;D18、D20、D21、D23、D25、D28等6份材料表现为中抗（MR）,占供试材料的17.65%。剩余27份材料为高感（HS）或中感。综合对白粉病抗性与农艺性状表现,半蔓生型豌豆抗白粉病资源 D23可作为地方优良品种直接加以利用,其余6份抗病材料则可作为抗病亲本资源。     

小麦地方品种Wx基因构成分析

用ＳＤＳ－ＰＡＧＥ电泳技术,从９００份小麦（Ｔ．ａｅｓｔｉｖｕｍ）地方品种鉴定出普通小麦Ｗｘ－７Ｄ基因缺失材料一份,Ｗｘ－４Ａ基因缺失材料六份,含三个基因的材料为８９３份,出现频率为正常类型〉Ｗｘ－４Ａ〉Ｗｘ－７Ｄ〉Ｗｘ－７Ａ,Ｗｘ－７Ｄ缺失然因的发现,再次证明我国小麦资源是一特殊类群,这些材料的发现,为我国开展面各品质育种研究打下了坚实的材料基础,在小麦淀粉遗传控制研究和品质育种方面具有深远的理     

小麦糯性突变体的筛选

利用SDS－PAGE技术，从河北省小麦地方品种及国内外小麦育成种1270份中，发现Wx-B1突变体63份，Wx-D1突变体4份，Wx－E2份。红蘖麦和白芒白等品种的发现，丰富了品质育种的亲本；长穗偃麦草的蜡质基因与小麦蜡质基因不同，可以进行更深入的分子水平研究。研究表明，地方品种和育成种具有相似的突变规律；国外优良品质材料含有较高的Wx-B1突变频率；国内以源自北京、山西、陕西、云南的材料突变频率最高；河北、河南、山东、江苏等省份突变频率居中；而四川、天津、黑龙江和安徽等省份的样本量太小，突变频率也最低。该频率分布规律为信后育成种筛选的重点提供了帮助。     

Market-based incentives for conserving diversity on farms: the case of rice landraces in Central Tarai,Nepal

Market-based incentives are one means of encouraging farmers to grow landraces that are also of social value, thereby contributing to the conservation of crop genetic diversity on farms – and in principle, the cheapest. This study uses a participatory, market systems approach supplemented by baseline data from an ongoing project to analyze markets for rice landraces and modern varieties in Nepal. Nepal is located in the area of origin and diversity for Asian rice. With the exception of traditional Basmati rice (which is of high aromatic quality), most rice landraces are traded through small-scale informal channels. Traders earn higher profits handling modern varieties than landraces, with the exception of Basmati, which competes with modern varieties. The superior consumption qualities of Basmati are valued in markets, but conserving these landraces may not have great social value. Furthermore, farmers who grow Basmati are clearly better off than those who do not. Findings raise questions about the role of market-based incentives for conserving landraces on farms, the costs entailed in establishing a structure to generate them, and about efficiency vs. equity considerations in the design of conservation programs.     

Rice Diversity Collection,Conservation and Management in Northeastern India

Rice is the principal crop of northeastern region of India, where a considerable range of diversity exists. The germplasm collection has also unfold the occurrence of large number of rice landraces in the region. Between 1985 and 2002, a total 2639 accessions of rice germplasms including their wild relatives have been collected. Most of these germplasm material have been conserved in the National Gene Bank, New Delhi following their necessary characterization and evaluation. With the establishment of the Regional Gene Bank Module with medium-term storage facilities (6–7°C with 40–45% relative humidity) at Barapani, Meghalaya, the rice germplasm conservation (ex situ) have been initiated in the region.     

Assessment of storage protein variation in relation to some morphological characters in a sample of Spanish landraces of common wheat (Triticum aestivum L. ssp. aestivum)

Fifty nine Spanish landraces of common wheat belonging to differentagrotypes were evaluated with four morphological spike characters and 11 seedprotein loci in order to study the level of agreement between the agrotypeclassification and the morphological and biochemical variation of the wheats. Asa result of the work 22 new gliadin alleles were found and 12 of them werecatalogued. Multivariate and cluster analysis performed on the two sets of data(morphological plus biochemical and biochemical only) showed that there was aclear relationship between seed protein composition and the wheat classificationfor the agrotypes Barbilla, Candeal andNegrete. For the other groups, agrotype classification was notconsistent with the variation for biochemical characters although, some allelesin common were found except for the Jeja type. Morphologicaltraits revealed that they could be useful as first step in discriminating amongagrotypes. In contrast, biochemical markers showed that genetic variation amongaccessions was higher than among agrotypes. The protein lociGli-B1,Gli-A2,Gli-D2 andGli-A1 were shown to be the mostpolymorphic and useful in discriminating between the accessions studied.     

Maintenance of Squash (<Emphasis Type="Italic">Cucurbita</Emphasis> spp.) Landrace Diversity by Farmers' Activities in Mexico

Squash (Cucurbita spp.) is a common component in traditional cropping systems in Mexico, mainly in the agroecosystem known as the “milpa”, in which squash is cultivated in association with maize (Zea mays), the main crop. Using a questionnaire, 80 farmers were interviewed about crop production and selection practices in order to understand how these factors affect genetic diversity of local squash populations. We found that the most of the farmers who cultivate squash were elderly 59.8 ± 14.5 (mean ± SD; n = 78) years old. Squash varieties in the area were exclusively locally adapted landraces, and had not been replaced by modern squash cultivars. Two cultivated squash species, C. argyrosperma ssp. argyrosperma and C. moschata, had been grown intercropped with maize by 97.5% of the interviewed farmers, but only 50.0% were still producing squash at the time of the study. Farmers recognize typical characteristics of particular varieties within each of the local cultivated squash species, and selection is directed to maintain their identity. Nearly two thirds of the farmers (62.0%) had exchanged seeds of squash for planting, a practice that serves to increase genetic variability in the populations. All of the interviewed farmers were conscious of the possible hybridization between the wild gourd (C. argyrosperma ssp. sororia) and their cultivated squash. Despite various natural and human managed factors identified as contributing to enhancement of genetic diversity in these populations, results of the study show that genetic erosion of Cucurbita is likely in the region in the near future.