木薯种质资源的遗传多样性分析与评价

采用SRAP分子标记对134份木薯种质资源进行的遗传多样性分析,36对多态性引物对全部材料进行扩增,共获得348个稳定的谱带,其中多态性谱带306条(占87.9%),平均每对引物扩增条带数和多态性带数分别为9.7个和8.5个。应用Nei’s相似系数法估算了134份材料间的相似系数为0.536～0.971,说明木薯种质资源间的遗传基础一般。聚类分析将全部材料划分为8个组群,结合PCA分析说明,分组群体构成与其品系的地理来源具有一般相关性。平均遗传多样性指数为0.4630,各个组内存在差异,以第1、5组较高,分别由我国的自育品种和来自南美洲的品系构成。研究结果较全面反映了中国现有木薯种质资源遗传多样性特点,为我国进一步引进木薯优良资源,以及优异木薯基因资源挖掘和育种利用提供了理论借鉴。     

SCoT分子标记技术在木薯遗传多样性分析中的应用

应用SCoT标记对不同来源的28份木薯种质资源进行遗传多样性和亲缘关系分析。结果表明：从36条引物中筛选出19条重复性好、条带清晰的引物对28份木薯材料进行PCR扩增。共扩增出171条带,其中多态性条带123条,平均每条引物扩增多态性条带6.5条,多态性条带比率为71.9％。经NTSYS-pc2.10e软件计算分析,28份木薯种质间遗传相似系数在0.631~0.930之间。利用UPGMA法进行聚类的结果显示：在系数0.68处,木薯材料分为2大类,品种BRA354单独成为一类;在系数为0.734处,28份木薯种质资源主要聚为5大类,聚类结果与材料来源有一定相关性。SCoT标记能在木薯种质间检测出一定程度的遗传多样性,可为木薯遗传育种提供新的技术支持。     

木薯种质资源淀粉特性分析与评价

为了评价和筛选出淀粉品质优良的木薯资源,对212份国内外栽培木薯种质块根淀粉产量性状及淀粉含量、直链淀粉含量、支链淀粉含量、粘度峰值和糊化温度5个重要淀粉特性指标进行研究.结果表明,不同木薯资源各淀粉特性差异较大,不同指标间有一定的相关性,利用概率分级法将8个淀粉产量及特性性状分为5级,即极低、低、中、高和极高,推荐极...     

遮荫对木薯块根淀粉含量和品质的影响

以2个木薯主栽品种(SC124、SC8)为材料,自盛暑期开始遮荫(植后70 d至植后160 d),对植后160 d木薯块根进行淀粉含量及相关酶活性分析,结合扫描电镜观察遮荫处理与正常光照下木薯块根淀粉结构的变化,探讨弱光对木薯贮藏淀粉含量和品质的影响。结果表明,遮荫处理改变了木薯光合产物在"源"与"库"之间的分配,造成茎叶变长,茎干细弱,块根减重,根冠比显著降低。弱光显著影响淀粉含量及其组成,遮荫处理提高或显著提高了SC124和SC8块根直链淀粉含量,降低了2个品种块根的总淀粉含量和支链淀粉含量,以及支链淀粉与直支链淀粉的比率。遮荫处理后木薯块根AGPase活性均降低;GBSS活性增加(SC8)或无显著变化(SC124);而遮荫处理对SSS和SBE活性影响不一致。扫描电镜观察表明,遮荫处理形成许多直径较小的淀粉粒,影响淀粉充实程度而造成淀粉含量降低。     

大豆蛋白质和油分含量遗传研究进展

蛋白质和油分含量是大豆2个重要品质性状,其遗传研究对大豆品质改良尤为重要。该文从表型遗传分离规律、基因遗传模型、基因作用方式、遗传相关、遗传力及QTL定位等方面,概括了大豆蛋白质、油分含量的遗传研究进展。并提出利用野生大豆资源研究大豆蛋白质和油分含量遗传机理,为大豆品质改良提供理论参考。     

基于SSR标记的山西野生大豆种质资源遗传多样性分析

分析山西野生大豆资源的遗传多样性和遗传结构有助于了解山西野生大豆起源与进化,为野生大豆优异种质挖掘及资源高效利用等提供理论基础。本研究采用52对SSR分子标记对来自于山西省9个地区32个县市的70份野生大豆资源进行了遗传多样性分析。结果表明:共扩增出450个等位基因,平均每对引物扩增出8.7个等位基因,变幅为3～19。等位基因频率为0.185 7～0.885 7,平均0.421 0;基因遗传多样性指数为0.210 2～0.871 8,平均0.710 0;多态性信息含量为0.201 9～0.858 4,平均0.679 7。将所有供试材料按地理来源分类,并进行遗传多样性分析。结果表明,中部野生大豆资源的平均等位基因数、平均基因多样性指数和平均多态信息含量最高,北部次之,南部最低。而各组的平均主要等位基因频率结果与之相反。基于遗传结构和基于遗传距离的聚类分析都可将试验材料分为3个类群,两种分类结果基本相同。第一类群主要包括山西中部部分资源,第二类群主要包括山西中部部分资源和山西北部资源,第三类群主要包括山西南部资源。聚类结果与地理来源较为一致。山西野生大豆资源遗传多样性较高。中部野生大豆资源的遗传多样性最高,北部资源次之,南部资源最低。推测山西中部和北部曾经发生过种质交流,导致中部资源遗传多样性最高,该区域可能为山西野生大豆的遗传多样性中心。     

木薯及其同源四倍体基因组与DNA甲基化差异分析

为研究染色体加倍对木薯基因组的影响,以及多倍化与2种不同倍性木薯之间DNA碱基序列的变化的联系。本研究以木薯品种"新选048"二倍体及其同源四倍体为研究材料,使用微卫星(simple sequence repeat,SSR)、目标起始密码子多态性(stand codon targeted polymorphism,SCo T)和甲基化敏感扩增多态性(methylation sensitive amplification polymorphism,MSAP)技术分别对木薯倍性间的遗传差异、DNA甲基化水平和模式进行分析。结果表明:利用SCo T和SSR均未检测出多态性条带产生,利用MSAP技术可检测出在DNA甲基化水平和模式均发生较大改变。二倍体和同源四倍体的总甲基化率分别为60.21%、59.52%,全甲基化率分别为39.92%、41.42%,半甲基化率分别为20.29%、18.10%。木薯多倍化后,其中有27.30%的位点发生了过甲基化,四倍体有25.00%的位点表现出去甲基化。本研究结果为探究木薯倍性间遗传差异和表观遗传变化规律进行了前期探索。      

24份木薯(Manihot esculenta)种质的遗传多样性研究

采用产量性状和12个表型性状聚类分析以及SSR标记技术,对不同产地来源的24份木薯(Manihot esculenta)种质遗传多样性进行了研究。结果表明,依据12个表型性状在欧氏距离系数为39.353处可将供试的24个木薯种质分为3类,一些品种的表型性状与地理来源之间存在相关性;利用18对SSR引物对24份木薯种质进行多态性分析,共检测到154条带,其中多态性带145条,每一个位点上检测到5～12条,平均8.6条。材料间相似系数在0.510～0.967之间,平均相似系数为0.695。以相似系数0.78为结合点,可以将材料分为三大类。不同国家和地区来源的材料不能明显聚类,不同淀粉含量、干物质量分数的品种却聚在一起,且没有发现与淀粉含量、干物质量分数相关的特异性条带。农艺性状的聚类结果与SSR聚类的结果有很大的差异,说明木薯在长期的演化和自然选择过程中发生了显著的表型变化。     

施氮量对木薯氮素营养特性及产量形成的影响

采用大田试验,研究了不同施氮水平下木薯氮素营养特性的变化及其对产量形成的影响。试验设置0、120、240、360 kg/hm24个氮水平,综合分析了各生育期木薯根、茎、叶等组织中的氮含量、氮素积累量、氮素吸收强度、氮素分配和干物质积累分配、产量品质以及经济效益等指标的变化。结果表明:施氮能显著增加木薯根、茎、叶等组织的氮含量和氮积累量,提高氮素吸收强度,并改变氮素养分的分配特性;此外,随着施氮量的增加,木薯块根干物质积累量、鲜薯产量、淀粉产量、经济效益等均显著提高。综上所述,最佳施氮量为240 kg/hm2,适宜的施入比例为:幼苗期∶茎秆分叉期∶块根形成期∶块根膨大早期∶块根膨大中期=1∶1.71∶1.33∶0.73∶0.57。     

木薯种茎离体脱水胁迫下生理生化响应研究

木薯是热带和亚热带地区重要的粮食和经济作物。木薯种茎是目前唯一的繁殖方式,然而采收后木薯种茎如何应对脱水胁迫及糖代谢基因的表达尚不清楚。本研究通过检测对照组和保水处理组的木薯种茎在采后不同时间点水分和糖分的含量变化来探究离体条件下木薯种茎内糖类发挥的作用。通过检测糖类代谢相关基因的表达来解析不同糖分间的代谢关系及离体种茎的活性状态。结果表明,在保水处理组中随着采后时间的延长,种茎中的果糖、葡萄糖和蔗糖的含量先降低后升高,而海藻糖含量变化正好相反。同时,保水处理组的果糖、葡萄糖和蔗糖的含量显著高于对照组,而海藻糖含量显著低于对照组。qPCR分析发现,严重的脱水胁迫显著地提高了糖酵解基因的表达。这些结论表明,脱水胁迫显著影响木薯茎中糖类的相互转化。推测脱水胁迫前20 d通过合成海藻糖来响应脱水胁迫,在20~30 d则通过分解海藻糖为木薯种茎提供必要的能量物质。同时本研究通过甘油处理提高了木薯种茎的贮藏时间,为木薯种茎的贮藏提供新的方法。     

Variation in qualitative and quantitative traits of cassava germplasm from selected national breeding programmes in sub-Saharan Africa

An improved understanding of phenotypic variation within cassava germplasm in southern, eastern and central Africa will help to formulate knowledge-based breeding strategies. Thus, the overall objective of this study was to examine the phenotypic variation in cassava germplasm available within six breeding programmes in Africa, namely Uganda, Kenya, Tanzania, Rwanda, Democratic Republic of Congo and Madagascar. In each country, single-row plots were used for assessment of 29 qualitative traits and evaluation of four quantitative traits: root dry matter content (DMC), harvest index (HI), leaf retention (LR) and root cortex thickness. Qualitative traits provided limited discrimination of cassava germplasm. However, differences in DMC, HI, LR and root cortex thickness were observed among the germplasm indicating scope for genetic improvement. Highest average DMC was registered in Uganda (39.3%) and lowest in Tanzania (30.1%), with the elite genotypes having a relatively higher DMC than local genotypes. Highest average HI was observed in Uganda (0.60) and lowest in Kenya (0.32). Cassava genotypes displayed varied root peel thickness (0.34-4.89 mm). This study highlights variation in agronomic traits that could be exploited to increase cassava productivity.     

籼稻稻米营养品质性状的种子、细胞质和母体遗传相关分析（英文）

 利用9个籼型不育系和5个籼型恢复系进行不完全双列杂交，同时分析了早籼稻米蛋白质含量、蛋白质指数、赖氨酸含量、赖氨酸指数以及赖氨酸含量与蛋白质含量的比值等营养品质成对性状间种子、细胞质和母体等多种遗传相关。结果证实蛋白质含量与蛋白质指数等多数成对性状间的种子加性和显性相关、细胞质相关以及母体加性和显性相关系数均为显著正值，对这些性状进行间接改良有效。但赖氨酸含量与蛋白质含量的比值同蛋白质性状的关系则以显著负相关为主，表明选择高蛋白质含量或蛋白质指数的单株将会显著降低该比值。正向的种子和母体显性相关以及细胞质相关可以同时显著提高杂交稻组合中赖氨酸含量和赖氨酸指数以及赖氨酸含量与蛋白质含量比值。对于主要受加性相关控制的成对性状进行间接选择具有较好的效果，而杂交稻育种中则以利用显性相关为主。     

Leaf retention and cassava productivity

Increased longevity of leaves, or improved leaf retention, has been suggested as a possible means to increase productivity of cassava (Manihot esculenta Crantz). This study evaluated variation in leaf retention and its relation to cassava productivity under irrigated and stressed conditions. In the first trial 1350 clones were evaluated on the North Coast of Colombia with a 5-month dry period towards the end of the growth cycle. Clones with the leaf retention trait produced more total fresh biomass and yielded 33% more root dry matter than plants without the trait. In the irrigated trial 110 clones were evaluated on the CIAT farm at about 1000 mamsl. Leaf retention was quantified using a 1–5 visual score with five corresponding to excellent leaf retention. Genetic correlations between leaf retention and fresh foliage production (0.49), root dry matter yield (0.46), fresh root production (0.43) and root dry matter content (0.25) were obtained. Increased root yield under stressed and unstressed conditions was associated with increased total biomass production and increased harvest index. These finding concur with the results of cassava growth models that include leaf longevity as a variable. The lack of any negative genetic correlations between leaf retention and useful agronomic traits coupled with the relatively high genetic correlation for root yield and the high heritability (0.55) for leaf retention indicate that it should be relatively easy and advantageous to incorporate this characteristic in breeding and selection programs directed to increasing root yield under both water stressed and unstressed conditions.     

鹧鸪茶种质资源品质性状的多样性分析

针对海南省的92份鹧鸪茶种质为材料,采用主成分分析和聚类分析,对水浸出物、茶多酚含量、游离氨基酸含量、咖啡碱含量和氨酚比等5个主要品质性状进行多样性分析。结果表明,鹧鸪茶种质资源主要品质性状的遗传变异丰富。游离氨基含量的多样性指数最高,其次是茶多酚含量;咖啡碱含量的变异系数最大,其次是氨酚比。主成分分析表明,前2个主成分累计贡献率达77.70%,能够反映5个品质性状的大部分信息。基于各种质在5个品质性状上的差异,对92份鹧鸪茶种质进行聚类分析,发现第Ⅰ、Ⅱ、Ⅲ类3个类群,第Ⅲ类群综合表现最好,抗氧化的保健功效突出,且咖啡碱含量最低,可作为良好的育种材料。本研究结果可为鹧鸪茶的开发利用以及优良无性品系选育提供科学依据。     

Breeding Cassava for Underprivileged

SUMMARY

Cassava (Manihot esculenta Crantz), an important crop in the poorer rural uplands of the tropics, was an obvious target for international research attention in 1970 and the Centro Internacional de Agricultura Tropical (CIAT, headquartered in Colombia) established a cassava-breeding program. Assisted by many ancillary disciplines, the program defined its mission as breeding for low input conditions in less favorable environments to alleviate the poverty of small farmers through income generation. From its initiation, CIAT worked in a partnership with national programs. The breeding effort depended on the free exchange of germplasm, based on the understanding that CIAT would collect, evaluate, and maintain cassava germplasm and that this and any advanced materials derived from it would be freely available to any public organization. A key decision was to transfer the major applied breeding effort to Asia, while maintaining a basic breeding scheme in Colombia, with the understanding that a crop is usually more successful outside the center of crop origin and diversification than at the center. Fresh root yield of populations was improved by more than 100% and root dry matter content by more than 20%. The national program collaborators used these populations to develop many improved cultivars in many countries. The biological factors considered as critical for this successful breeding effort were: inclusion of a broad base of genetic variability obtained in the center of crop origin and diversification; evaluation of breeding materials under diverse environmental conditions; and a clear understanding of the different operational principles at different stages of breeding advancement. By 2002, Asian national programs had released more than 50 CIAT-related cassava cultivars in nine countries and farmers grew these new cultivars on more than one million ha. The economic benefits resulting from the increased productivity are well beyond one billion US$. The target population of small farmers in the poorer rural areas of the tropics captured a large proportion of these economic benefits. The understanding of crop germplasm being a common human heritage and the determination of agricultural scientists to use this for the welfare of the neediest people were the social factors for the overall success.     

假木豆属种质资源植物学性状遗传多样性分析

假木豆（Dendrolobium triangulare）为多年生灌木,假木豆叶量大、产量高,营养价值高,是优良的高蛋白青饲料。目前仅有山蚂蝗亚族之间的遗传多样性研究,假木豆属的形态学遗传多样性的分析研究比较匮乏,缺少大范围的种质形态学遗传多样性研究。对优质育种资源植物学性状综合评价是育种的前提。为了培育优质豆科牧草品种,满足南方畜牧生产需求,本研究采用随机区组设计,研究材料为76份假木豆属种质资源,对35个植物学性状进行观测,分析假木豆属的遗传多样性特点,为假木豆选育工作提供基础材料。通过形态学观测分析研究其遗传多样性,结果表明：35个植物学性状中叶背面毛况（CV=46.92%）,茎的颜色（CV=39.77%）和叶柄毛况（CV=39.52%）变异系数（CV）最大,说明假木豆属遗传多样性较为丰富;多个植物学性状之间存在相关性,叶长与叶宽（r=0.887）之间存在极显著正相关,长宽比在2.0左右,叶形比较接近椭圆形。茎的形状与叶长（r=–0.459）、叶宽（r=–0.491）存在相关性,这表明如果假木豆产量以叶面积为主,应尽量选择圆柱形的茎。中央小叶叶形与荚果长（r=0.360）存在极显...     

太湖地区水稻地方品种品质性状多样性研究进展

太湖地区种稻历史悠久,积累了丰富的水稻地方品种资源,水稻地方品种的遗传多样性研究可为优质资源的保护利用以及选育新品种提供一些参考。本文从遗传多样性的概念、研究方法、太湖地区水稻地方品种品质性状多样性研究进展等方面进行了综述,总结了太湖流域水稻地方品种资源的相关利用价值。     

应用RAPD技术对44份木薯材料遗传背景的研究

应用RAPD技术对44份木薯材料的遗传背景进行研究。结果表明,采用筛选出的19条随机引物(10bp)PCR扩增共获得279条带,其中234条出现多态性。引物S32和S76可将供试44份材料全部区分开。计算出44份木薯材料的成对相似系数,绝大多数栽培材料间的相似系数大于0.75。通过UPGMA聚类分析,将44份木薯材料划分为野生种和栽培种2大类,依结合线不同,栽培材料又可细分为若干个类群。不同国家和地区来源的材料不能明显聚类。对中国热带农业科学院自身育成的材料单独进行UPGMA聚类,结果与系谱相吻合。利用RAPD研究结果对部分木薯材料的亲缘关系进行了鉴定,并探讨了RAPD技术运用于木薯育种中亲本选配的可能性。      

Identification of quantitative trait loci for protein content, oil content and oil quality for groundnut (Arachis hypogaea L.)

Very few efforts have been made to improve the nutritional quality of groundnut, as biochemical estimation of quality traits is laborious and uneconomic; hence, it is difficult to improve them through traditional breeding alone. Identification of molecular markers for quality traits will have a great impact in molecular breeding. An attempt was made to identify microsatellite or simple sequence repeat (SSR) markers for important nutritional traits (protein content, oil content and oil quality in terms of oleic acid, linoleic acid and oleic/linoleic acid ratio) in a mapping population consisting of 146 recombinant inbreed lines (RILs) of a cross TG26 × GPBD4. Phenotyping data analysis for quality traits showed significant variation in the population and environment, genotype × environment interaction and high heritability was observed for all the traits. Negative correlation between protein content and oil content, oleic acid and linoleic acid indicated their antagonistic nature. After screening >1000 SSR markers, a partial genetic linkage map comprising of 45 SSR loci on 8 linkage groups with an average inter-marker distance of 14.62 cM was developed. QTL analysis based on single marker analysis (SMA) and composite interval mapping identified some candidate SSR markers associated with major QTLs as well as several minor QTLs for the nutritional traits. Validation of these major QTLs using a wider genetic background may provide the markers for molecular breeding for improving groundnut for nutritional traits.