引进日本优质水稻品种125份,四川雅安生态条件下进行种植观察,步评价其主要农艺性状表现,中筛选出株型、产量构成因素、生育期等综合农艺性状较为理想的W132、W155等24份优良品种资源,更好地利用这些稻种资源提供依据.

1 579份水稻种质, 分析与评价其遗传多样性和优良稻种资源，主要结果如下: (1)亚洲、非洲与大洋洲间遗传距离较远，且亚洲、非洲和大洋洲的水稻资源具有较丰富的表型遗传多样性，而不同性状的遗传多样性在洲际间表现不同；粒长宽比、碱消值、株高、粒宽、千粒重和淀粉含量等6个性状具有很高的表型遗传多样性。(2)采用主成分分析法和逐步回归分析法综合评判表明，越南的PI392768的综合性状表现最好，法国的PI281760综合性状表现最差，同时淀粉含量、抽穗期、株高、倒伏性、糙米色和颖壳色等6个性状可作为种质资源综合评价指标。在水稻育种中应注重利用具有丰富遗传多样性的种质资源，并在亲本选配时适当选择遗传距离较远且综合性状表现差异大的种质材料。]]>

The present study was conducted to understand the pattern of variation and the genetic bases for cold tolerance at the early growth stage in Asian rice. The genetic variation was investigated at the germination, plumule and seedling stages among 57 strains including cultivated rice (Oryza sativa ssp. indica and ssp. japonica) and its wild progenitor (Oryza rufipogon). The significant differentiation of cold tolerance was observed among the taxonomically divided groups. At the germination stage, both indica and japonica subspecies tended to be more tolerant than O. rufipogon, whereas at the plumule and seedling stages, ssp. japonica tended to be more tolerant than ssp. indica and O. rufipogon. Furthermore, in cold tolerance at the plumule stage, the clinal variation across the latitude of origins was observed within O. rufipogon and ssp. japonica, suggesting that the current pattern of variation seems to have been shaped by both their phylogenetic histories and on-going adaptation to the local environments. QTL analysis between O. sativa ssp. japonica (tolerant) and O. rufipogon (susceptible) revealed five putative QTLs for cold tolerance at the plumule and seedling stages but not at the germination stage. Substitution mapping was also carried out to precisely locate the two major QTLs for cold tolerance at the plumule stage, which could be used for improvement of tolerance to cold stress in ssp. indica.]]>

以珍汕97B与多年生稻种质AAV002863的DH群体(198个株系)构建了包含140个SSR标记的连锁图谱，检测了影响水稻低温发芽力性状的数量性状座位（QTL）。15℃下处理6 d，两亲本珍汕97B与多年生稻AAV002863的发芽率分别为79.7%和30.1%，DH群体间的发芽率变化在0%~100%。QTL定位分析检测到2个与低温发芽力相关的基因座，分别位于第3和第10染色体上，贡献率分别为12.6%和12.9%，增效等位基因分别来自多年生稻AAV002863和珍汕97B。上位性分析结果显示，第1与第10染色体上存在影响低温发芽力的互作位点，其互作可以提高低温发芽力，参与互作的第10染色体上的位点也具有加性主效应。

对籼型两系骨干亲本9311（受体）和粳稻日本晴（供体）构建的单片段代换系群体，在芽期和苗期分别进行低温处理，以芽期处理后的恢复成活率和苗期卷叶程度作为耐冷性的评价指标进行耐冷性评价。结果表明，日本晴在芽期和苗期耐冷性极显著强于9311，不同代换系芽期和苗期耐冷性也存在极显著差异，芽期和苗期耐冷性较强的代换系X724、X732、X733较好地保持了9311的农艺性状，其产量等性状的一般配合力优于9311；鉴定出18个芽期耐冷性QTL和5个苗期耐冷性QTL，分布于12条染色体上的20个代换片段中，第12染色体的RM1261-RM519和RM17区域同时检测出芽期和苗期耐冷性QTL；芽期耐冷性QTL qCTP9、qCTP11.2、qCTP12.1和苗期耐冷性QTL qCTS1.1、qCTS1.2具有较大加性效应，对应代换系耐冷性较强。

【目的】棉花（Gossypium hirsutum）虽是较耐盐碱的作物，但不同品种间耐盐性差异较大。本研究旨在探讨新疆各年代不同基因型棉花苗期耐盐特性，挖掘棉花本身耐盐遗传资源，筛选耐盐性快速鉴定指标并建立可靠的棉花耐盐性数学评价模型，为棉花耐盐新品种选育及大规模品种耐盐性评价奠定基础。【方法】以17个棉花品种为试验材料，按NaCl盐与草炭、蛭石复合基质重量比设置0（CK）、0.6%两个处理水平，棉种经消毒、催芽后播于复合基质，通过苗期盐土栽培持续胁迫的方式，可反映棉株在大田条件中的实际胁迫环境及真实抗逆机制。对各处理下各品种出苗率（ER）、幼苗鲜重（FW）、干重（DW）、植株含水量（PWC）、第一片真叶面积（LA）、叶片净光合速率（Pn）、叶绿素含量（Chl）和相对电导率（REC）等11个生理指标进行测定，以各单项指标的耐盐系数作为衡量耐盐性的依据，运用主成分分析、聚类分析和逐步回归等方法对其耐盐性进行综合评价及分类，并分析各耐盐类型棉花品种生理表现特征。【结果】通过主成分分析，本试验将盐胁迫处理下棉花幼苗叶片的11个单项指标转换成6个彼此独立的综合指标；通过隶属函数分析，得到不同棉花基因型幼苗耐盐性综合评价值（D值），并通过聚类分析，将17个棉花品种划分为4种耐盐类型，其中盐敏感型3个品种，弱耐盐及中度耐盐型各6个，高度耐盐型2个；进一步利用逐步回归方法建立了可靠的棉花幼苗耐盐性评价回归模型D=-1.192+ 0.402REC+0.119LA+0.274FW+0.086Pn+1.019Chl，方程决定系数R2= 0.9921，同时筛选出显著影响棉花幼苗耐盐能力的5个单项指标，即Pn、Chl、LA、FW和REC，对回归方程的估计精度进行评价，各品种估计精度均大于94.44%，表明所筛选鉴定指标对棉花耐盐性影响明显，该方程可用于棉花耐盐性评价。本研究对逐步回归与聚类结果进行相互验证，得到各耐盐类型棉花幼苗的生理表现特征。结果发现，与盐敏感品种相比，强耐盐棉花品种幼苗在盐胁迫下REC较低，Pn、Chl、LA和FW则能保持较高水平，且其幼苗真叶面积可达其它类别品种近2倍。【结论】强耐盐棉花品种幼苗叶片在盐碱环境中受到伤害较轻，能保持较高的真叶面积和光合能力，有利于提高植株耐盐能力和光合产物积累，降低土壤中离子毒害，增强植株耐盐性。在相同逆境中，通过测定REC、Pn、Chl、LA和FW等5个鉴定指标，可进行品种耐盐性强弱的快速鉴定和预测。

Germplasm diversity is the mainstay for crop improvement and genetic dissection of complex traits. Understanding genetic diversity, population structure, and the level and distribution of linkage disequilibrium (LD) in target populations is of great importance and a prerequisite for association mapping. In this study, 100 genome-wide simple sequence repeat (SSR) markers were used to assess genetic diversity, population structure, and LD of 416 rice accessions including landraces, cultivars and breeding lines collected mostly in China. A model-based population structure analysis divided the rice materials into seven subpopulations. 63% of the SSR pairs in these accessions were in LD, which was mostly due to an overall population structure, since the number of locus pairs in LD was reduced sharply within each subpopulation, with the SSR pairs in LD ranging from 5.9 to 22.9%. Among those SSR pairs showing significant LD, the intrachromosomal LD had an average of 25-50 cM in different subpopulations. Analysis of the phenotypic diversity of 25 traits showed that the population structure accounted for an average of 22.4% of phenotypic variation. An example association mapping for starch quality traits using both the candidate gene mapping and genome-wide mapping strategies based on the estimated population structure was conducted. Candidate gene mapping confirmed that the Wx and starch synthase IIa (SSIIa) genes could be identified as strongly associated with apparent amylose content (AAC) and pasting temperature (PT), respectively. More importantly, we revealed that the Wx gene was also strongly associated with PT. In addition to the major genes, we found five and seven SSRs were associated with AAC and PT, respectively, some of which have not been detected in previous linkage mapping studies. The results suggested that the population may be useful for the genome-wide marker-trait association mapping. This new association population has the potential to identify quantitative trait loci (QTL) with small effects, which will aid in dissecting complex traits and in exploiting the rich diversity present in rice germplasm.

Cold in the initial growth stages is an important stressfactor for maize grown in regions with a temperate climate,particularly in case of early sowing. Sources of tolerancehave been identified in adapted genotypes, but promisinggenes for cold tolerance should also be found in materialdeveloped under the lower-temperature margins of the cropdistribution. This research was conducted in order to testAndean maize accessions for cold tolerance expressed duringboth the heterotrophic and early autotrophic growth stages.Experiments were conducted in controlled environments tostudy cold tolerance traits (germination %, germinationindex and plant growth rate) at continuous 10°C (heterotrophic growth) and at varying 10–16°C (autotrophic growth). An experiment was also performed inthe field with early sowing (both heterotrophic and autotrophic growth). In each experiment, a control trialwas conducted in more favourable conditions (i.e. continuous25°C in a controlled environment or late planting inthe field) so that cold tolerance traits could also beexamined as the ratio between the stress and the controltrial. None of the accessions was superior for all coldtolerance traits. However, several Andean maize accessionsoutperformed the US Corn-belt hybrid checks for one or moretraits, both in heterotrophic and autotrophic growth. Overall, BOZM 855, PMS 636, Poblacion D, Poblacion E andBOZM 696 were the best accessions, suggesting that they canbe a promising source of genes for improving cold toleranceof adapted maize genotypes.]]>

Low-temperature germination is one of the major determinants for stable stand establishment in the direct seeding method in temperate regions, and at high altitudes of tropical regions. Quantitative trait loci (QTLs) controlling low-temperature germinability in rice were identified using 122 backcross inbred lines (BILs) derived from a cross between temperate japonica varieties, Italica Livorno and Hayamasari. The germination rate at 15 degrees C was measured to represent low-temperature germination and used for QTL analysis. The germination rate at 15 degrees C for 7 days of Italica Livorno and Hayamasari was 98.7 and 26.8%, respectively, and that of BILs ranged from 0 to 83.3%. Using restriction fragment length polymorphism (RFLP) and simple sequence repeat (SSR) markers, we constructed a linkage map which corresponded to about 90% of the rice genome. Three putative QTLs associated with low-temperature germination were detected. The most effective QTL, qLTG-3-1 on chromosome 3, accounted for 35.0% of the total phenotypic variation for low-temperature germinability. Two additional QTLs, qLTG-3-2 on chromosome 3 and qLTG-4 on chromosome 4, were detected and accounted for 17.4 and 5.5% of the total phenotypic variation, respectively. The Italica Livorno alleles in all detected QTLs increased the low-temperature germination rate.

以粳稻9516、H45、武育粳、转PEPC基因水稻、Kitaake、苏沪香粳，籼稻扬稻6号、香籼、IR64，培矮64S以及杂交稻粤优938、汕优63、X07S/紫徽100、两优培九等14个水稻品种为材料，分别鉴定了芽期（胚根1 cm, 胚芽0.5 cm）、苗期（三叶）和孕穗期的耐冷性，同时选取南京对水稻播种敏感的自然低温条件，进行低温鉴定。结果表明，芽期存活率、苗期的枯死率和孕穗期结实率均为可靠的水稻耐冷性鉴定指标。进一步从叶片的光合速率、PSⅡ光化学效率（Fv/Fm）、脂肪酸组分、活性氧指标(丙二醛,过氧化氢和超氧阴离子和抗氧化物质(抗坏血酸和谷胱甘肽)的变化等方面，研究耐冷性不同的水稻的耐冷生理机制。表明耐冷的水稻品种武育粳含较多的不饱和脂肪酸，在低温逆境下，膜的流动性愈大，低温对其伤害愈小；对杂交稻汕优63而言，其叶内抵御逆境的保护系统抗坏血酸和谷胱甘肽的循环被较大地激活，特别是谷胱甘肽再生的高速运转，与不耐冷的品种香籼相比，汕优63叶内的过氧化物质累积较少，其耐冷性表现中等。看来水稻叶片维持高的脂肪酸不饱和指数和谷胱甘肽的周转循环能力是水稻耐冷的重要特征。]]>

【目的】分析特异水稻种质糯稻89-1越冬性及主要农艺性状的遗传变异。【方法】（1）利用不同海拔高度，观察糯稻89-1各节位腋芽和稻秆在冬季的成活率。（2）用糯稻89-1与红芒糯、明恢63、辐恢838、测64杂交建立F1、F1与亲本回交群体和F2群体，分析越冬性及主要农艺性状在不同生长季的遗传变异。【结果】（1）糯稻89-1能通过腋芽休眠，抗御不同海拔高度的低温越冬，下年萌发再生。稻秆成活率和腋芽萌发率分别达82.6%，29%，越冬再生季产量为6291.0 kg•ha-1，与正季相当。（2）通过遗传分析和χ2检验表明：糯稻89-1的越冬性由多基因控制，其遗传力在不同杂交组合中表现不尽一致。（3）千粒重和株高具有较高的遗传力，正季最大，越冬再生季最小，每穗粒数和结实率在再生季的遗传力最大。（4）糯89-1/明恢63杂交F2穗平均总粒数、千粒重、株高和穗长呈正态分布，结实率呈双峰分布。【结论】糯稻89-1是一份能通过腋芽休眠抗御低温越冬的可利用特异稻种遗传资源。