6个燕麦品种种子萌发期抗旱性比较

为探讨燕麦萌发期抗旱性,以6个燕麦品种种子为材料,用不同浓度(0、5％、10％、15％、20％、25％)PEG溶液模拟干旱条件,测定种子的发芽势、发芽率、幼苗活力指数、主根长、苗高等5个指标,利用方差分析法、隶属函数法及主成分分析法进行综合评价.结果表明,6个燕麦品种的萌发期抗旱性依次为:美达>魅力>牧王>贝勒2代>领...     

大豆起源与进化研究进展

本文对近年来大豆起源与进化研究取得的进展与存在的问题进行了综述，旨在促进大豆起源与进化基础生物学研究，为促进野生种质在大豆改良中的应用提供依据。     

用组织培养法繁殖野生亚麻的研究

野生亚麻是优异的种质资源，由于其种子具有较强的休眠性，用常规方法繁殖难度较大，本试验利用组织培养方法，通过对实生苗幼嫩的茎杆及叶片诱导愈伤组织再分化苗的途径，对野生亚麻的试管苗扩繁进行了研究，获得了一定数量的野生亚麻再生无根苗。研究结果表明，野生亚麻愈伤分化成苗对培养基的选择性不强，用组织培养法快速繁殖是行之有效的途径。     

玉米种质创新——进展与展望

种质创新是链接种质资源和育种的关键环节,玉米种质创新在玉米育种中发挥着重要作用。对基于野生近缘植物、地方品种、外来群体、杂交种和自交系的玉米种质创新进展进行评述,对今后我国玉米种质创新发展方向进行展望。     

野生大豆抗旱性鉴定及研究

1999年对410份野生大豆进行抗旱性初步评价基础上，2000—2002年对13份野生大豆做进一步抗旱性评价，并与半野生大豆、栽培大豆的抗旱性进行比较。结果表明：野生大豆中存在高度抗旱基因型，其中ZYD1936、ZYD3654的平均抗旱系数大于0．6500，系1级抗旱材料，且抗旱性稳定。平均抗旱系数与株高、结荚高度、分枝数、主茎节数、单株荚数、单株粒数均呈负相关，与单株粒重和百粒重呈正相关。高度抗旱野生资源的特点：生育日数120天左右，株高200cm左右，主茎明显，主茎节数较多，分枝数较少且短，结荚部位较低；中型椭圆叶，紫花，棕毛，无限结荚蔓生习性；小粒、黑种皮、椭圆粒，以二、三粒荚为主，一粒荚次之，四粒荚较少，一级抗旱材料的四粒荚比栽培大豆多。     

欧洲野生甘蓝的核质遗传多样性和群体遗传结构分析

为了解欧洲野生甘蓝遗传背景,以栽培甘蓝、甘蓝型油菜和白菜型油菜作对比,对引进的7个生态地理群体共80份野生甘蓝材料进行了核质遗传多样性和群体遗传结构分析。利用10对特异性SSR引物分析叶绿体基因组多样性,获得8个差异性标记,将参试94份材料划分为3类,即甘蓝（含栽培和野生甘蓝）、甘蓝型油菜和白菜型油菜;包括6种单倍型,其中野生甘蓝2个,甘蓝型油菜3个,白菜型油菜1个。利用6对SRAP引物对核基因组多样性进行分析,获得75个多态性标记;聚类及遗传结构分析表明7个野生甘蓝群体中,F、D、G三个群体聚为独立的亚类,E群体大部分单株归于G亚类。其它3个群体A、B、C则相互混杂在一起。野生甘蓝群体Nei’s基因多样性指数（H）和Shannon’s 指数（I）分别为0.301 3和0.461 1。分子方差分析(AMOVA)表明野生甘蓝以群体内变异为主,占80%;群体间变异仅占20%。结果显示引进的野生甘蓝群体核质遗传多样性丰富。     

野生大豆天然群体百粒重类型组成与地理分布调查

百粒重是野生大豆重要的植物学性状之一,是Soja亚属内种的进化程度的标志.通常野生大豆天然群体都是各种百粒重组成的混合群体.我们调查了12个天然群体百粒重类型构成.结果显示,群体间的多样性(H'β=2.420),明显高于群体内的多样性(H'α=0.875),说明群体的百粒重组成的变异主要是由于群体的地理位置效应而引起.在这些天然群体内,百粒重的变动在0.76-6.0g之间,1.0-1.5g和1.5-2.0g是群体的主要优势型,小于1.0g或者较大的2.0-2.5g类型很少成为群体的优势型.大多数群体有单一优势型,少数有两个优势型.北部和中部的群体的平均百粒重大于南部群体,变异程度也高.关联分析显示百粒重越是接近的类型,他们的重叠分布性也较大;2.0g以下类型之间的重叠分布性较高,同样2.0g以上类型之间的重叠性也较高.聚类结果暗示,野生大豆天然种群组成结构与地理分布存在一定的相关性.     

水分胁迫对灌浆期燕麦叶片光合特性的影响

在盆栽条件下,研究了灌浆期燕麦在水分胁迫条件下光合有效辐射对叶片净光合速率、胞间CO2浓度及气孔导度的影响。结果表明,净光合速率对光合有效辐射的响应均呈直角双曲线变化,水分胁迫不仅使净光合速率减小,而且光补偿点、光饱和点及呼吸速率也明显降低;水分胁迫还使叶片胞间CO2浓度、气孔导度减小,且随光合有效辐射增强减小幅度增大;分析认为,气孔导度和光合速率直接影响胞间CO2浓度变化,但在水分胁迫条件下前者则是影响胞间CO2浓度变化的主要因素,也就是水分胁迫致使净光合速率下降更主要是由于气孔因素作用的结果。     

Comparative genetic analysis and molecular mapping of fertility restoration genes for WA,Dissi, and Gambiaca cytoplasmic male sterility systems in rice

The genetic relationship among three cytoplasmic male sterility (CMS) systems, consisting of WA, Dissi, and Gambiaca, was studied. The results showed that the maintainers of one CMS system can also maintain sterility in other cytoplasmic backgrounds. The F₁ plants derived from crosses involving A and R lines of the respective cytoplasm and their cross-combination with other CMS systems showed similar pollen and spikelet fertility values, indicating that similar biological processes govern fertility restoration in these three CMS systems. The results from an inheritance study showed that the pollen fertility restoration in all three CMS systems was governed by two independent and dominant genes with classical duplicate gene action. Three F₂ populations, generated from the crosses between the parents of good-performing rice hybrids, that possess WA, Dissi, and Gambiaca CMS cytoplasm, were used to map the Rf genes. For the WA-CMS system, Rf3 was located at a distance of 2.8 cM from RM490 on chromosome 1 and Rf4 was located at 1.6 cM from RM1108 on chromosome 10. For the Dissi-CMS system, Rf3 was located on chromosome 1 at 1.9 cM from RM7466 and Rf4 on chromosome 10 was located at 2.3 cM from RM6100. The effect of Rf3 on pollen fertility appeared to be stronger than the effect of Rf4. In the Gambiaca-CMS system, only one major locus was mapped on chromosome 1 at 2.1 cM from RM576. These studies have led to the development of marker-assisted selection (MAS) for selecting putative restorer lines, new approaches to alloplasmic line breeding, and the transfer of Rf genes into adapted cultivars through a backcrossing program in an active hybrid rice breeding program.     

Cloning and characterization of a novel low molecular weight glutenin subunit gene at the Glu-A3 locus from wild emmer wheat (Triticum turgidum L. var. dicoccoides)

Amplification of the coding region, and upstream and downstream sequences of a low-molecular-weight glutenin subunits (LMW-GS) gene from wild emmer wheat (Triticum turgidum L. var. dicoccoides, 2n = 4x = 28, AABB) accession TD22 was carried out using designed allele-specific PCR (AS-PCR) primers. The complete 1,176 bp sequence of a novel LMW-i type subunit gene at the Glu-A3 locus, named LMW-TD22, is described. Analysis of the nucleotide and deduced amino acid sequences showed that this gene possessed striking characteristics although its molecular structure was generally similar to those of previously reported i-type LMW-GS genes that were isolated from common wheat and related species. The deduced amino acid sequence of LMW-TD22 gene contained 390 amino acid residues with the predicted molecular weight being 43,009.3 Da, which appeared to be the longest gene among the cloned LMW-i type genes from bread wheat and related species. The distinct feature of LMW-TD22 was two long polyglutamine stretches of 12 and 17 glutamines occurring in the repetitive and C-terminal domains as well as a cysteine residue present in the seventh amino acid residue of the signal peptide. These polyglutamine repeats are believed to improve the structure of gluten polymer and increase the strength of dough formed from the polymer. In addition, the putative 44 k subunit encoded by LMW-TD22 was verified by N-terminal microsequencing, gel electrophoresis and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) analysis. Certain types of post-translational modifications, such as phosphorylation and glycosylation, may be associated with this LMW-i type subunit. A. Wang and Y. Xiao made equal contribution to the research as the first author.