RAPD分子标记与玉米杂种产量优势预测的研究

以２４个优良玉米自交系统ＮＣⅡ设计组配成１４３个单杂交种为材料，利用的ＲＡＰＤ分子标记技术研究玉米杂种优势群划分，遗传距离与特殊配合力，杂种产量，杂种产量优势的联系。结果表明：（１）ＲＡＰＤ技术可用于玉米杂种优势群划分。（２）亲本遗传距离杂种产量优势，杂种产量，特殊配合畋有一定相关关系，但决定系数很小，分别是１０％，１０％，１５％，利用ＲＡＰＤ技术预测杂种优势，杂种产量作用有限，应进一步研究与杂     

利用RFLP、SSR、AFLP和RAPD标记分析玉米自交系遗传多样性的比较研究

利用 ＲＦＬＰ、ＳＳＲ．ＡＦＬＰ和ＲＡＰＤ ４种分子标记方法研究了 １５个玉米（Ｚｅａ ｍａｙｓ Ｌ．）自交系的遗传多样性,同时对４种标记系统进行比较。在供试材料中筛选到具多态性的ＲＦＬＰ探针酶组合５６个,６６对ＳＳＲ引物,２０个ＲＡＰＤ引物和９个ＡＦＬＰ引物组合,分别检测到多态性带１６７、２０１、８７和１０８条。ＳＳＲ标记位点的平均多态性信息量（ＰＩＣ）最大（０．５４）,ＡＦＬＰ标记位点最小（０．３６）,但ＡＦＬＰ标记具有最高的多态性检测效率（Ａｉ,３２．２）。４种分子标记所得遗传相似系数相关性显著,比较相关系数表明 ＲＡＰＤ可靠性较低。依据 ４种分子标记结果将 １５个供试自交系划分为塘四平头、旅大红骨、兰卡斯特、瑞德和ＰＮ共５个类群,与系谱分析基本一致。认为ＳＳＲ和ＲＦＬＰ两种分子标记方法适合进行玉米种质遗传多样性的研究。     

玉米自交系间遗传距离与产量杂种优势,杂种产量的关系

以13个玉米自交系及其按双列杂交配制的78个单交种为材料,研究性状选择、亲本选择对遗传距离与产量杂种优势、杂种产量关系的影响,结果表明:(1)当性状数较少时,遗传距离与产量杂种优势、杂种产量的关系因性状的不同而异;当性状数较多时,遗传距离与产量杂种优势、杂种产量的关系为抛物线,受性状影响较小;(2)当所选亲本材料的遗传差异较大时,遗传距离与产量杂种优势的关系为抛物线;当所选亲本材料的遗传差异较小时,遗传距离与产量杂种优势的关系为直线或不相关。     

玉米CMS材料线粒体DNA遗传多型性的研究

选用１１×４＝４４个探针／酶组合,５０个（１０ｍｅｒ）随机序列引物对２５种不同胞质来源的ＣＭＳ玉米,５种正常胞质玉米线粒体ＤＮＡ进行ＲＦＬＰ和ＲＡＰＤ研究。研究结果表明：（１）４５％的探针／酶组合可检测到玉米线粒体ＤＮＡ的多型性,共表现１５种ＲＦＬＰ类型,其中Ｓ组ＣＭＳ材料内有７种,正常胞质材料内有２种;８０％的随机引物可检测到ＲＡＰＤ。（２）基于ＲＦＬＰ资料的聚类分析结果,可将３０种胞质明确地划分为Ｔ、Ｃ、Ｓ、Ｎ４组,其结果与恢复专效性测定结果一致。其中ｐＨＪ２－７－１／ＢａｍＨＩ的ＲＦＬＰ类型可成为利用ＲＦＬＰ技术进行胞质分组的鉴定体系。（３）“双”型胞质线粒体ＤＮＡ常表现Ｓ＋Ｃ胞质的ＲＦＬＰ图谱。     

利用RFLP,SSR,AFLP和RAPD标记分析玉米自效系遗传多样性的比较研究

利用ＲＦＬＰ、ＳＳＲ、ＡＦＬＰ和ＲＡＰＤ４种分子标记方法研究了１５个玉米（Ｚｅａ ｍａｙｓ Ｌ．）自交系的遗传多样性,同时对４种标记系统进行比较。在供试材料中筛选到具多态性的ＲＦＬＰ探针酶组合５６个,６７６对ＳＳＲ引物,２０个ＲＡＰＤ引物和９个ＡＦＬＰ引物组合,分别检测到多态性带１６７、２０１、８７和１０８条。ＳＳＲ标记位点的平均多态性检测效率（Ａｉ,３２．２）。４种分子标记所得遗传相似自交系划分     

表皮生长因子对肺泡巨噬细胞趋化性的调控

采用测定趋化性的方法,观察了表皮生长因子（ＥＧＦ）和纤维连接蛋白（ＦＮ）对肺泡巨噬细胞（ＡＭ）趋化运动的影响。结果显示,ＥＧＦ能抑制ＡＭ的趋化性,量效关系显著（ｒ＝－０．９９１０,Ｐ＜０．０１）,而ＥＧＦ本身对ＡＭ并不表现趋化吸引作用。ＦＮ亦能抑制ＡＭ的趋化性（Ｐ＜０．０１）,ＥＧＦ和ＦＮ两者协同作用时,对ＡＭ趋化性的抑制程度大于各自的单独作用（Ｐ＜０．０１）。实验证明ＥＧＦ具有调节ＡＭ趋化运动的非促丝裂功能。提示肺内的细胞因子ＥＧＦ和细胞外基质成分ＦＮ参与肺部炎症及免疫反应的调控。     

病理性近视与HLA的关联性研究

用ＰＣＲ－ＲＦＬＰ方法对江浙沪籍汉族５５例病理性近视眼（ＰＭ）患者的ＨＬＡⅡ类ＤＱＢ１基因的第二个外显子进行了基因分型。结果发现ＨＬＡ－ＤＱＢ１＊０２０１、＊０３０３、＊０４０１等位基因在ＰＭ患者中和正常人中的分布有显著的差异（Ｐｃ＜０．０５,ＡＦ分别为０．１６３６,０．１０９１,０．１６３６,０．１０９１ｖｓ．０．０４００,０．０３００,０．０４００,０．０２００）,可能与ＰＭ的致病相关。ＤＱＢ     

水稻红莲型细胞质雄性不育系与保持系mtRNA差异显示和差别片段？…

将Ｔ４ＲＮＡ连接酶和ＡＦＬＰ技术特点相结合构建于适于ｍｔＲＮＡ的差异显示方法,并比较水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）红莲型细胞质雄性不育系,保持系和杂种一代ｍｔＲＮＡ差异。在４组引物对的选择扩增产物中共找到６个差异片段,其中差异条带ＤＴＡ为不育系仅有,条带ＤＡＢ为不育系和保持系特有,而条带ＤＢＦ１、ＤＢＦ２、ＤＢＦ３、ＤＢＦ４为保持系和Ｆ１杂种共有。这表明水稻红莲型不育系粤泰Ａ与杂种一代泰优     

应用5SrDNA间隔序列分析鉴定体细胞杂种

近年来,由于分子生物学的飞速发展,极大地推动了生命科学各分支学科在ＤＮＡ水平上的研究力度。就体细胞杂种的鉴定而言,仅形态、细胞学、生化方面的证据还远远不足,直接从ＤＮＡ水平上鉴定其杂种性质已成为必然。目前,从分子水平上鉴定体细胞杂种的方法有多种,如ＲＦＬＰ图谱分析、ＲＡＰＤ分析等。由于ＲＦＬＰ分析需要特异探针,ＲＡＰＤ分析的重复性较差,在一定程度上限制了两种方法在体细胞杂种鉴定方面的应用。据报道［１］,５ＳｒＤＮＡ（即５ＳｒＲＮＡ基因）在至今研究的所有真核生物中是以串联重复单位组成的,与卫星ＤＮ…     

由小麦＊玉米获得的普通小麦加倍单倍体后代的RFLP变异

用小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）的ｒＤＮＡ克隆ｐＴａ７１和与小麦基因组有部分同源性的玉米（ＺｅａｍａｙｓＬ．）ＤＮＡ克隆作探针,对由小麦＊玉米获得的普通小麦加倍单倍体后工群体进行ＲＦＬＰ分析。     

Breeding for Biomass Yield in Switchgrass Using Surrogate Measures of Yield

Development of switchgrass (Panicum virgatum L.) as a dedicated biomass crop for conversion to energy requires substantial increases in biomass yield. Most efforts to breed for increased biomass yield are based on some form of indirect selection. The objective of this paper is to evaluate and compare the expected efficiency of several indirect measures of breeding value for improving sward-plot biomass yield of switchgrass. Sward-plot biomass yield, row-plot biomass, and spaced-plant biomass were measured on 144 half-sib families or their maternal parents from the WS4U-C2 breeding population of upland switchgrass. Heading date was also scored on row plots and anthesis date was scored on spaced plants. Use of any of these indirect selection criteria was expected to be less efficient than direct selection for biomass yield measured on sward plots, when expressed as genetic gain per year. Combining any of these indirect selection criteria with half-sib family selection for biomass yield resulted in increases in efficiency of 14 to 36%, but this could only be achieved at a very large cost of measuring phenotype on literally thousands of plants that would eventually have no chance of being selected because they were derived from inferior families. Genomic prediction methods offered the best solution to increase breeding efficiency by reducing average cycle time, increasing selection intensity, and placing selection pressure on all additive genetic variance within the population. Use of genomic selection methods is expected to double or triple genetic gains over field-based half-sib family selection.     

Comparing the Effects of Rust on Plot Yield, Plant Yield, Yield Components, and Vegetative Parts of Soybean

To determine the plant variable for coupling a disease model to a soybean growth model, effects of soybean rust (caused by Phakopsora pachyrhizi) on soybean were quantified at four levels: vegetative parts, yield components, plant yield, and plot yield. Path analysis was conducted to determine the most correlated components to disease in each level. The responses of vegetative parts, such as shoot weight and branches/plant, to disease effects were inconsistent among cultivars. Yield components responded consistently to disease effects among the cultivars, indicated by the high values of correlation coefficients between disease and the components. Path coefficients indicated that reduction of 100-seed weight was the most important cause of yield loss in this level. No significant within-plant compensation was detected using path coefficient analysis except for that between pod length to pod width. The most consistent response to disease effect was at population level. Correlation of disease to plant yield was as significant as these to plot yield. Correlations between disease and these plant levels were in the order of plot yield, plant yield, yield components, and vegetative parts. Regression between plot yield and green leaf area duration (GLAD) from flowering to seed full size was highly significant (P < 0,001). This study suggests that green leaf area at population level was the best variable for coupling disease model to crop model.     

利用分子标记预测杂交水稻产量及其构成因素

利用AFLP、RAPD、SSR技术分析了10个恢复系和5个不育系的931个基因座,利用15个亲本配制了50个杂交组合,在泸州和重庆2个环境下同时种植,考察了产量及其构成因素,从931个基因座中筛选出了与之相关的阳性座位、增效座位、减效座位、非环境型座位,并分析了它们与杂种产量及其构成因素间的关系。结果表明,利用所有座位计算的遗传差异与产量及其构成因素的相关性,绝大多数性状未达显著水平,不能直接用于预测产量及其构成因素。阳性座位在一定程度上可以提高相关系数,因性状不同而存在差异,在多数性状上预测产量及其构成因素还有一定难度;增效座位和减效座位可以大幅度提高相关系数,在不同的环境下也表现一致,可以用来预测产量及其构成因素;非环境型座位计算的相关系数也较高,但低于增效座位和减效座位,说明环境对产量及其构成因素有较大的影响。     

利用重组自交系进行陆地棉产量及产量构成因子性状的QTL定位

以高产陆地棉栽培品种中棉所12和8891的杂交组合湘杂棉2号为材料,采用单粒传法构建了含有180个家系的重组自交系(RILs)群体。本研究的目的是分析产量及其构成因子的相互关系并进行相应的QTL定位。重组自交系群体、两亲本和F1于2002年、2003年分别种植于南京农业大学江浦实验农场和江苏省灌云棉花基地。收获每行中间五株的籽棉并考察产量及产量构成因子性状。调查的产量及产量构成因子性状包括单株籽棉产量、单株皮棉产量、单株铃数、铃重、衣分、衣指和籽指。筛选了4,106对SSR引物和384个AFLP引物组合,分别得到127和18个多态位点;此外,2个RAPD引物、1个SRAP引物组合以及来自亲本8891的显性黄花药基因P1也被用来作为标记检测群体基因型。最终共获得149个多态位点,其中132个位点分布于26个染色体/连锁群,覆盖865.20cM,约占棉花基因组的18.57%,标记间平均距离6.55cM。利用此遗传图谱结合重组自交系群体3个环境下的产量及产量构成因子性状,应用QTLCartographer2.0的复合区间作图法进行单位点QTL定位。对各环境资料的分离分析共定位出34个QTL,而利用三环境平均值的联合分析定位出15个QTL。本研究定位的QTL可为棉花产量育种提供信息,其中衣分QTLqLP-A10-1在联合分析及分离分析下的两个环境都能检测到,可能对标记辅助选择有实际应用价值。通径分析结果表明,各产量构成因子中,铃数对皮棉产量贡献最大,这与产量构成因素性状在F1的杂种优势表现一致;因此,在棉花育种上,可优先考虑单株铃数并结合其它产量构成因素进行品种选育和杂交组合选配。     

Compounded Perturbations Yield Ecological Surprises

All species have evolved in the presence of disturbance, and thus are in a sense matched to the recurrence pattern of the perturbations. Consequently, disturbances within the typical range, even at the extreme of that range as defined by large, infrequent disturbances (LIDs), usually result in little long-term change to the system's fundamental character. We argue that more serious ecological consequences result from compounded perturbations within the normative recovery time of the community in question. We consider both physically based disturbance (for example, storm, volcanic eruption, and forest fire) and biologically based disturbance of populations, such as overharvesting, invasion, and disease, and their interactions. Dispersal capability and measures of generation time or age to first reproduction of the species of interest seem to be the important metrics for scaling the size and frequency of disturbances among different types of ecosystems. We develop six scenarios that describe communities that have been subjected to multiple perturbations, either simultaneously or at a rate faster than the rate of recovery, and appear to have entered new domains or “ecological surprises.” In some cases, three or more disturbances seem to have been required to initiate the changed state. We argue that in a world of ever-more-pervasive anthropogenic impacts on natural communities coupled with the increasing certainty of global change, compounded perturbations and ecological surprises will become more common. Understanding these ecological synergisms will be basic to environmental management decisions of the 21st century. Received 14 July 1998; accepted 18 September 1998.     

Crop Diversity for Yield Increase

Traditional farming practices suggest that cultivation of a mixture of crop species in the same field through temporal and spatial management may be advantageous in boosting yields and preventing disease, but evidence from large-scale field testing is limited. Increasing crop diversity through intercropping addresses the problem of increasing land utilization and crop productivity. In collaboration with farmers and extension personnel, we tested intercropping of tobacco, maize, sugarcane, potato, wheat and broad bean – either by relay cropping or by mixing crop species based on differences in their heights, and practiced these patterns on 15,302 hectares in ten counties in Yunnan Province, China. The results of observation plots within these areas showed that some combinations increased crop yields for the same season between 33.2 and 84.7% and reached a land equivalent ratio (LER) of between 1.31 and 1.84. This approach can be easily applied in developing countries, which is crucial in face of dwindling arable land and increasing food demand.     

Crop Yield and Planting Density

From the established responses of plants to photosynthetic activityand to the availability of nutrients in the soil, a crop yield:planting density response equation is derived with parametersthat are of biological significance. crop yield, planting density, mathematical model     

Critical Yield Factors for Achieving High Grain Yield in Early-Season Rice Grown under Mechanical Transplanting Conditions

Double-season rice cropping systems occupy a large portion of the rice production area in southern China. Because the problem of insufficient labor, mechanical transplanting (in contrast to the manual transplanting) was become more attractive in double-season rice system. However, the decisive yield factors which resulting in high grain yield of early-season rice are unclear under mechanical-transplanted conditions. In present study, the field experiments were conducted in the early season in 2017 and repeated in 2018 in Santang Town, Hunan Province, China. Ten early season rice cultivars (Zhuliangyou 819, Lingliangyou 268, Lingliangyou 104, Luliangyou 996, Xiangzaoxian 24, Xiangzaoxian 32, Xiangzaoxian 45, Xiangzaoxian 42, Zhongjiazao 17, and Zhongzao 39) were used as materials in this study. The difference in grain yield and closelyrelated agronomic and physiological traits of ten tested cultivars were compared. The range of yields (t ha^–1 at 86% dry matter) in 2017 was 6.2 to 8.7 (mean 7.8) and in 2018 was 6.5 to 8.4 (mean 7.8). Grain weight and pre-heading biomass accumulation had potent significant positive correlations with the grain yield. The greater pre-heading biomass accumulation was major attributed to higher apparent radiation use efficiency. Our results suggested that early-season rice cultivars to achieve the high grain yield in mechanical-transplanted conditions depends on apparent radiation use efficiency in the pre-heading period and higher grain weight.