Identification of Italian landraces of bean (Phaseolus vulgaris L.) using an image analysis system

Colour, shape and size of whole seeds and their spots of some Italian landraces of bean (Phaseolus vulgaris L.) were measured using a specifically developed macro, based on image analysis library KS-400 V 3.0 (Carl Zeiss, Germany).     

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     

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。     

Relationship between yield and mineral nutrient concentrations in historical and modern spring wheat cultivars

The diet of approximately three billion people worldwide is nutrient deficient and most of the world’s poorest people are dependent on staple food crops as their primary source of micronutrients. One component of the solution to nutrient deficiencies is collaboration among plant breeders, cereal chemists and nutritionists to produce staple crop cultivars with increased mineral nutrient concentration. Sixty-three historical and modern wheat cultivars were evaluated for grain yield and concentration of calcium, copper, iron, magnesium, manganese, phosphorus, selenium, and zinc. While grain yield has increased over time, the concentrations of all minerals except calcium have decreased. Thus a greater consumption of whole wheat bread from modern cultivars is required to achieve the same percentage of recommended dietary allowance levels contributed by most of the older cultivars. The decrease in mineral concentration over the past 120 years occurs primarily in the soft white wheat market class, whereas in the hard red market class it has remained largely constant over time. This suggests that plant breeders, through intentional selection of low ash content in soft white wheat cultivars, have contributed to the decreased mineral nutrient concentration in modern wheat cultivars. These results contradict the theory that there exists a genetically based, biological trade-off between yield and mineral concentrations. Therefore, using the abundant variation present in wheat cultivars, it should be possible to improve mineral concentrations in modern cultivars without negatively affecting yield.     

Genetic diversity of Swiss maize (<Emphasis Type="Italic">Zea mays</Emphasis> L. ssp. <Emphasis Type="Italic">mays</Emphasis>) assessed with individuals and bulks on agarose gels

About 65 years ago, more than 150 Swiss maize landraces (Zea mays L. ssp. mays) of the flint type were collected and conserved ex situ. Due to the climatically and culturally diverse environment of the Alps, a considerable genetic diversity of this material was assumed. To prove this, an efficient method was required to carry out genetic profiling of all the accessions in the Swiss Gene Bank. Simple sequence repeat marker (SSR) profiling in combination with the visualization of the polymerase chain reaction (PCR) products on agarose gels was chosen. Here a set of 19 different landrace accessions was analyzed to: (i) investigate their genetic diversity, (ii) investigate and display the population structure and (iii) determine whether DNA bulks rather than single plants can be used for such analyses. Four repeated samples of one accession were found to be much closer to one another than to the rest of accessions. Furthermore, specific alleles were identified for several accessions. The PCR products of the bulked DNA samples represented only a small part of the variation revealed by the analysis of individuals. Loci with four base repeat motifs performed better in the analysis of bulks than loci with other repeat motifs. The correlation between genetic distance matrices, based on the analysis of individuals and bulks, respectively, was significant. Thus, the single plant approach allowed for sufficient differentiation of accessions, and DNA bulks visualized on agarose gels led to correlated genetic distances although a limited number of alleles were detected. Although the limited resolution of agarose gels likely causes some bias, profiling of larger sets with the individual plant approach appears feasible and more informative compared to the bulk analysis we conducted.     

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.     

13个玉米地方种质的配合力分析

选用5个自交系为测验种,采用不完全双列杂交遗传交配设计,对四川盆地及盆周山区13个玉米地方种质的配合力进行了分析。结果表明：屏山大黄、筠连血丝和筠连大白马牙具有较大的利用潜势;13个地方种质可分为5个初级杂种优势群。根据特殊配合力(SCA)效应及产量表现,确定了旅大红骨×地方种质、热带种质×地方种质和PA亚群×地方种质是利用地方种质组配的强优势组合模式。     

河北水稻地方种质品质多样性分析

为了揭示河北水稻地方种质资源品质性状遗传多样性,采用多样性指数、主成分分析、聚类分析等方法对收集的109份河北水稻地方种质15个品质性状进行了遗传多样性评价。结果表明：河北水稻地方种质存在丰富的遗传多样性。15个品质性状平均变异系数为23.03%,平均多样性指数为1.92。垩白粒率、垩白度、粒长、蛋白质含量、米饭硬度5个性状多样性指数大于2,表明这些河北水稻地方种质在这些性状上遗传变异丰富。根据主成分分析,15个品质性状可归纳成为4个主成分因子,其累积贡献率包含了15个变量83.04％的信息。米饭食味、直链淀粉含量、精米率、垩白度是影响河北水稻地方种质品质的主要因素。采用4个主成分因子欧式距离聚类分析结果表明,在遗传距离D=16.5处,可以将109份地方种质分为4类,但不同来源的河北地方水稻种质交错分布聚类。本研究为河北地方水稻种质的利用提供了科学依据。     

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。