旱稻渗入系的构建与分析

以优良水稻品种沈农265为轮回亲本,以农家旱稻品种毫格劳为供体亲本,通过多代回交和连续自交的方法,构建了一套包含180个家系的旱稻渗入系.用GGT2.0绘制了旱稻渗入系的图示基因型,获得了2个亲本在渗入系中的比例和长度.该套渗入系覆盖了整个旱稻毫格劳基因组,标记间平均距离为8.37 cM,覆盖水稻基因组1566cM,90.5%的渗入片段长度集中在10～20 cM之间,单个最小渗入片段长度为1 cM,渗入片段平均长度为13 cM.说明该渗入系的构建非常有利于目标性状的定位.     

Assessing the risk of pollen-mediated gene flow from exotic Eucalyptus globulus plantations into native eucalypt populations of Australia

Eucalyptus globulus is the most commonly planted hardwood species in industrial plantations in Australia. It is typically planted well out of its natural range and may therefore present a significant risk of exotic pollen-mediated gene flow into native eucalypt populations. This risk was assessed by documenting levels of flowering within plantations, frequencies at which reproductively compatible native species are found adjacent to plantations, levels of F₁ hybridisation with native populations, and the existence of F₁ hybrid seedling recruitment. We surveyed over 300 plantations across southern Australia over two years. Flower abundance was found to be low with an average of 3% of trees found to flower on an inside row and 7% on the outside edge row of mature plantations. Considerable variation in flowering was found between locations (0–20% of trees reproductive) and 52% of plantations did not have compatible native species growing adjacent. Consequently, 65% of reproductive age plantations presented minimal or low risk of hybridisation due to lack of flowering and/or lack of adjacent compatible native species. Only three out of 10 surveyed high risk plantations were found to hybridise with native eucalypts (Eucalyptus camaldulensis, 0–3% hybrids in open-pollinated seed; Eucalyptus ovata, 0–2%). Established exotic E. ovata × globulus F₁ hybrid seedlings were also identified at just one site, in response to disturbance from fire. The potential for gene flow from E. globulus plantations into native eucalypt populations does exist, however, the implementation of an outlined risk management framework would greatly reduce the likelihood.     

野生二粒小麦和普通小麦及其渐渗系全麦与脱麸面粉蛋白分析

为了解野生二粒小麦籽粒蛋白特性对普通小麦全麦面粉和脱麸面粉的改良价值,以高产弱筋小麦品种川农16(CN16)为母本,分别与籽粒蛋白含量存在显著差异的四倍体野生二粒小麦D1和D97进行远缘杂交,按高产性状定向选择并连续自交获得稳定高世代渐渗系共61份,本研究对61份渐渗系、7份野生二粒小麦和6份普通小麦进行了全麦和脱麸面粉粗蛋白质含量及其各蛋白组分含量分析、比较。结果显示,野生二粒小麦的籽粒粗蛋白(GPC)及其清蛋白、球蛋白、醇溶蛋白、谷蛋白含量均较普通小麦具有更丰富的遗传多样性,各蛋白组分含量均显著高于普通小麦。61份渐渗系中,分别有54.10%和52.46%的材料全麦面粉和脱麸面粉的粗蛋白含量显著高于母本CN16,全麦和脱麸面粉蛋白质含量最高达17.77%和17.62%,较CN16分别提高了5.05和5.33个百分点;全麦和脱麸面粉的清蛋白、球蛋白、醇溶蛋白、谷蛋白分别有18.03%和32.79%、50.82%和62.30%、67.21%和77.05%、37.70%和81.97%的株系高于母本CN16。全麦和脱麸面粉的粗蛋白含量与醇溶蛋白和谷蛋白含量间、贮藏蛋白的各组分间、可溶性与不...     

水稻外源DNA导入系的创建及主要性状分析

通过花粉管通道法将稗草总体DNA和玉米总体DNA导入水稻受体R122中,获得的D1代变异频率分别高达1．487％和3．81％。对稳定的3个玉米DNA导入系和4个稗草DNA导入系研究表明,与受体R122相比,导入系在株型、株高、生育期、分蘖力、着粒密度、粒形、稃尖颜色、稻瘟病抗性、稻米品质、恢复力和耐储藏性等生物学性状方面发生了广泛的变异。同时讨论了外源DNA导入水稻的变异频率和在水稻育种中的应用前景。     

Evaluation of genetic diversity and relationships within an on-farm collection of Perilla frutescens (L.) Britt. using microsatellite markers

The present study demonstrates utilization of 11 microsatellite markers to explore genetic diversity held in Perilla frutescens (L.) Britt. landrace accessions growing on farms in different parts of Korea and Japan and to assess their genetic relationships. All microsatellite loci were polymorphic and produced a total of 96 alleles ranging from 4 to 20, with an average of 8.7 alleles per locus. Of the 96 alleles found, a total of 15 unique landrace-specific alleles were observed at 9 different loci. The locus GBPFM203 provided the highest number of alleles (20), of which five were unique and each specific to a particular landrace accession. The occurrence of unique, accession-specific alleles presented molecular evidence for the generation of new alleles within on-farm collection of Perilla. The mean values of observed (H _O) and expected heterozygosity (H _E) were 0.39 and 0.68, respectively, indicating a considerable amount of polymorphism within this collection. A genetic distance-based phylogeny grouped the two Perilla varieties, var. frutescens and var. crispa (Thunb.) Decne into two distinct groups. Accessions belonging to var. frutescens could also be divided into two subgroups at a close genetic distance (GD = 0.432). The overall clustering pattern did not strictly follow the grouping of accessions according to their geographic origins. These observations are indicative of extensive germplasm exchange among farms from different geographical regions. The genetic similarity observed among the Perilla landraces may be useful for future Perilla crop variety identification, conservation, and improvement programs.     

Development of introgression lines of an Indica-type rice variety, IR64, for unique agronomic traits and detection of the responsible chromosomal regions

A total of 334 introgression lines (INLs: BC₃-derived lines) derived from crosses between a recurrent parent of Indica rice cultivar IR64 and 10 donor parents, including new plant type (NPT) lines IR65600-87-2-2-3, IR65598-112-2, IR65564-2-2-3, IR69093-41-2-3-2, IR69125-25-3-1-1, Hoshiaoba, IR66215-44-2-3, IR68522-10-2-2, IR71195-AC1, and IR66750-6-2-1, have been developed. These INLs with IR64 genetic background were characterized for eight agronomic traits: days to heading, culm length, leaf width, leaf length, panicle length, panicle number, 100-grain weight, and total spikelet number per panicle at the International Rice Research Institute from 2005 to 2007. To identify introgressed segments from the donor parents, genotypes of the 334 INLs were detected using more than 200 polymorphic simple sequence repeat markers. These segments detected on chromosomes 1, 2, 4, 5, and 6 were commonly introgressed across the INLs from more than four donor varieties. Based on the data of phenotype and genotype for the 334 INLs, associations between agronomic traits and introgressed chromosomal segments in the 334 INLs were investigated. A total of 54 regions for the eight traits were detected: seven regions for days to heading, eight regions for culm length, eight regions for leaf width, four regions for leaf length, six regions for panicle length, three regions for panicle number per plant, seven regions for 100-grain weight, and 11 regions for total spikelet number per panicle. Among them, the region on the long arm of chromosome 4 was associated with characteristics of the NPT such as long leaf, broad leaf, and high spikelet number. The developed 334 INLs with the IR64 genetic background will be useful materials for genetic analysis of agronomic traits.     

Selection before backcross during exotic germplasm introgression

Introgression of genes from exotic germplasm into breeding populations can broaden the genetic base of crop improvement. Only a very small percentage of genetic variability has been used in crop breeding programs. Traditionally, F₁ plants are used to backcross to the adapted lines or populations. An alternative approach is to backcross the F₂ individuals selected for agronomic acceptability. Our objective was to determine whether selection before backcross would lead to more progenies with both high yield and acceptable levels of agronomic performance than direct backcross without selection. To test the feasibility of the proposed approach, we conducted parallel experiments in which two exotic sorghum accessions were crossed to two adapted sorghum parents and further backcrossing was conducted with either F₁ or selected F₂ plants. Fifty random S₁ families were evaluated in three test environments. Although selection before backcross resulted in a higher frequency of families with maturity equal to or earlier than those of the adapted parents, no consistent changes in grain yield and plant height were observed between populations with and without selection. Similar results were found with either an inbred or a population as the recurrent parents. Given these findings and the extra generation required, we do not recommend selection before backcross in the process of introgression of exotic germplasm.     

Expression of the “<Emphasis Type="Italic">glanded-plant</Emphasis> and <Emphasis Type="Italic">glandless-seed</Emphasis>” trait of Australian diploid cottons in different genetic backgrounds

The expression of the “glanded-plant and glandless-seed” trait was assessed using High Performance Liquid Chromatography (HPLC) analysis methods in different Gossypium hybrids obtained by crossing Australian diploid cottons and various diploid and tetraploid species. Significant variation in the gossypol content in the seed was observed among the analyzed genotypes. HPLC data demonstrated that the gossypol synthesis repression mechanism in the Australian diploid species belonging to C and G genomes was dominant but did not confirm its preferential functioning against A genome species bearing GL₂ locus. About 10% of the produced seeds had total gossypol content lower than the limit imposed by the World Health Organisation (600 ppm) for the use of cotton flour in food and feed. HPLC analysis of the terpenoids aldehyde (TA) contents in the aerial parts of the hybrids showed important qualitative and quantitative variability. This result could indicate a certain separation between pigment gland morphogenesis and terpenoid synthesis mechanisms in cotton.     

Genetic variation in tilapia populations in man-made reservoirs in Sri Lanka

An electrophoretic analysis of six populations of Oreochromis mossambicus (Peters) and four populations of O. niloticus (L.) from several rivers and a fish hatchery in Sri Lanka was conducted to determine the degree of mixing within and between stocks. Genetic characterization of the O. mossambicus stocks showed that some degree of mixing with O. niloticus occurred in all but two of the populations examined, while in the case of the O. niloticus, all the populations had some degree of mixing of O. mossambicus alleles. Genetic identity calculated using Nei's coefficient gave values ranging from 0.9484 to 0.9895 for O. niloticus populations and 1.0 to 0.9940 for O. mossambicus populations, while interspecies comparisons ranged from 0.7531 to 0.9002. The implications of these results for fisheries management and aquaculture are discussed.     

小麦重要农艺性状QTL近等基因导入系的选育

为了给小麦重要农艺性状的QTL精细定位及克隆奠定基础,对14个从Am3/莱州953(轮回亲本)BC4F4代选出的性状表现与莱州953有明显差异的导入系的8个农艺性状进行了分析,结果表明,每个导入系有2～7个性状与莱州953差异显著,在每一个性状上都有对农艺性状具有正向效应的位点.利用143对在亲本之间具有多态性的SSR标记对导入系含有的供体片段进行了检测,其中54对引物在14个导入系中检测到了供体片段,每一个导入系中检测到3～15个纯合供体片段及0～4个杂合片段,占受体基因组的1.7%～14.2%,平均为7.48%.利用其中10个导入系与轮回亲本莱州953杂交的F2群体进行了单片段代换系的选择,从10个导入系的F2中检测到40个供体片段,并从F2群体中选出了22个单片段代换系.这些导入系及其单片段代换系可用于有益的QTL的发掘、QTL精细定位与作图等研究.