Abstract:AFLP (amplified restriction fragment polymorphism) is an efficient molecular marker system for identification of varieties and genetic diversity research. Fifty-six improved wheat varieties released in Northwest Spring Wheat Region were analyzed by AFLP. Results of cluster analysis based on the AFLP data was basically consistent with the pedigrees of these varieties. At the same time, Correlation coefficient (r=0.86) between genetic distance matrices (Dice) based on the all AFLP bands and polymorphic bands indicated that all amplified bands should be included in order to realistically reflect the genetic relationship among varieties. However, for discrimination of varieties or capture of the accessions in core collections, we can only use the polymorphic band data. Multidimensional principal coordinate (PCO) analyses of these varieties based on the AFLP data showed that they can be clearly clustered into 5 groups, which is very helpful for further capturing these varieties. However, these varieties could not be clustered into groups clearly in the PCO figure based on the agronomic and botanic data, indicating the limitation of these data in revealing the genetic relationships among varieties. The low correlation coefficient (r=0.31) between the matrices based on agronomic and botanic data and AFLP data revealed the necessity to employ the molecular data in genetic diversity research and construction of a core collection.

Abstract:Polyethylene glycol (PEG)-6000, mannitol and sucrose were employed as osmotica for simulating water stress to identify drought resistance at germination stage of wheat. Three osmotica with osmotic potential from -0.25MPa to 1.50MPa were compared. Germinal bud growth in sucrose was inhibited because of molding and stress. Germinal bud elongation was inhibited in -0.25MPa PEG-6000 and -0.50MPa mannitol. Germination percentage significantly decreased in -0.50MPa PEG-6000 and -1.00MPa mannitol. Both of germination percentage and germinal bud length decreased with the increase of osmotic stress because the speed of water absorbing by grains was slow in osmotic stress solutions, and further resulted in lower grain relative water content (RWC) and lower osmotic potential than in water. All parameters associated with germination decreased more seriously in PEG-6000 than in mannitol at the same osmotic potential. For the purpose of evaluating drought resistance of wheat genotypes by identifying germination percentage in osmotic stress solution, -0.50MPa PEG-6000 or -1.00MPa mannitol is ideal, but -0.50MPa PEG-6000 should be preferred if the experiment cost is considered.

Abstract:Japonica rice GC13 was considered as a special wide compatibility variety (SWCV), because its compatibility was weak within subspecies and strong between subspecies. The result of genetic analysis of wide compatibility and allelism indicated that GC13 expressed an obvious effect of a major gene controlling wide compatibility, which may be modified by minor genes and be allelic to one of the locus S 7, S 9 or S 15 . GC13 could be combined inter-subspecifically with PGMS line Pei-ai 64S. GC13 is one of restorer gene donors of Japonica group, from which the restorer lines GR209, GR220 and GR238 were developed.

Abstract:The Triticeae plants distributed in the some areas of Shaanxi and Ningxia were investigated and collected in October 2002. A total of 145 populations involving 16 species of 6 genera were collected. Each species and its populations collected were analyzed for distribution areas, habitat, elevation and 2n chromosome number. Furthermore, some issues such as utilization of collections, basic unit of investigation and collecting, and conservation of Triticeae were discussed.

Abstract:In this study, the SSR fingerprint of 18 colored cotton lines has been obtained based on SSR technology. 110 pairs of SSR primers were screened, with 10 pairs which had excellent amplification result. Four SSR Primers were used to build a molecular searching pattern of these colored cotton lines. Meanwhile, cluster analysis was conducted using the 10 pairs of primers, and the genetic relationship were discussed.

Abstract:Totally 2745 sweetpotato accessions were identified for resistance to black rot from 1984 to 2002. Results demonstrated that about 7.7% of varieties or lines were highly resistant, 17.7% resistant, 23.2% medium resistant, 27.2% susceptible and 24.3% highly susceptible. The analyses of the resistance of 898 lines showed that resistant plants could be obtained from the progeny of any parental combinations. However, the higher parental resistance was, the more percentage of resistant plants in their progeny was. Results of correlation analysis indicated that there was not any correlation between resistance to black rot of varieties and its main economic characters. A lot of improved varieties of resistance to black rot with high yield and good qualities have been developed.

Abstract:Analysis of genetic diversity in maize germplasm is of great importance to conserving and utilizing these valuable genetic resources. However, when a large-scale analysis of genetic diversity in maize landraces and breeding populations which are genetically heterogeneous is conducted, the choice of sampling methods will seriously affect research results and efficiency. To solve the problem of sampling methods, individuals and bulking samples of different individuals of two breeding populations and three landraces were selected to be molecularly characterized using microsatellite (SSR) markers. The results showed that there were differences of intra-population genetic variability among different populations. Different bulking samples with the same number of individuals showed similar results, but bulking samples with different individuals presented some different results to some extent and the differences seemed to associate with the extent of genetic variability of the entries. Considering both scientific significance and research feasibility, we suggest that one bulk from randomly chosen 30 individuals (or two bulks each from randomly chosen 15 individuals) representing one population be genotyped when genetic diversity of maize landraces and breeding populations is assessed based on molecular markers, e.g. SSR.

Abstract:Seven foxtail millet varieties were studied for activities of superoxide dismutase (SOD),peroxidase (POX) and polyphenol oxidase (PPO) in different periods. The results showed that after foxtail millet were infected with head smut, three enzymes activities all increased significantly. Enzyme activities of resistance varieties were stronger than that of susceptible varieties. Changes of activities of protective enzymes were able to play an important role in resistance to head smut in foxtail millet.

Abstract:以已建立的微体繁殖体系为基础，对绿玉树再生丛芽进行Co^60γ射线不同剂量的辐射和不同浓度EMS诱变处理，以HYP为突变体选择压，筛选出抗HYP突变体小苗，并对突变体小苗进行抗寒测试。结果表明：辐射剂量影响丛芽的增殖、突变率及芽苗的生长，1．5KR为绿玉树丛芽辐射诱变比较适宜的剂量。0．2％的EMS亦能诱导绿玉树丛芽块产生突变芽，但与正常培养获得的再生小苗相比，诱变后产生的抗HYP芽苗生长缓慢，再生小苗矮小。抗HYP突变小苗的抗寒性比正常植物的抗寒性强。

Abstract:Identification and evaluation of 532 sorghum accessions newly stored in the National Genebank during 2001-2003 have been carried out with respect to four quality traits of protein,starch,lysine and tannin content. Furthermore, the correlations between quality traits of sorghum accessions were calculated. The results showed that characters of four quality traits appeared to be normal distribution, respectively. The different variations of the traits of sorghum accessions were revealed, therein, tannin content varied most. And among the four traits existed different relationships. Comparing with each quality trait of sorghum accessions of different origins, it could be found that lysine and tannin quality characters of bred sorghum were superior to that of landraces. Therefore, several high grade sorghum accessions possessing one or two even more good quality traits had been singled out through screening.

Abstract:In this study, Genes resistant to powdery mildew was introduced from Haynaldia villosa to wheat through crossing ,radiation and young embryo culture. High yield varieties and new germplasm with good agronomic characters resistant to powdery mildew were selected. By AFLP analysis , four lines resistant to powdery mildew were all translocation lines and resistant genes came from Haynaldia villosa ,Three markers probably closely linked to the resistant gene were obtained.

Abstract:A new Arabidopsis mutant eil,whose phenotype showed some lesions on leaves induced by high temperature, was found. The genetic analysis showed that the eil mutant was a homozygote of recessive single gene mutation. By analyzing the content of H 2O 2 and tissue staining of the wild-type and the mutant, we found that H 2O 2 had accumulated before the phenotype of mutant occurring. Lesions of the mutant on leaves did not occur under the high-temperature condition when the seedlings grew in culture medium with DPI (The inhibitor of NAD (P)H oxygen enzyme). The experiment showed that the function of Arabidopsis EIL gene was related to oxygen burst which leads to cell death. EIL is a gene conferring negatively controlled oxygen burst.

Abstract:A total of 3995 maize germplasm were identified for resistance to Sugarcane Mosaic Virus-Maize Dwarf strain B(SCMV-MDB) by frinky inoculation.Seventy-three good resistant inbred lines and 80 abundant resistant hybrids were screened by repeated identification.The resistance of maize heterotic groups were significant different.Most of germplasm of improved Reid , Lancaster and Ludahonggu groups were susceptible.Most of the Tangsipingtou and selected lines from Pioneer hybrids were resistant.Flint maize and dent maize and semident maize were resistant. Only a few germplasm were resistant in waxy corn. No resistant germplasm was found in sweet maize and popcorn.

Abstract:用人工接种大豆灰斑病茼的方法对224份供试材料，在生理小种水平上进行了抗性鉴定，筛选出抗8个以上生理小种的多抗资源47份，占供试材料的20．98％，其中东北农业大学的材料最多，比例达46．81％；黑龙江省主栽品种有5份，占多抗材料的10．64％。供试材料中，有抗单个小种和抗多个甚至全部生理小种的品种，表明在现行大豆品种资源中，具有较丰富的专化抗性资源和广谱性的抗源。

Abstract:In this study, 27 newly collected wild soybean materials and 38 conserved germplasm collected from the same places were used as materials. Sixty SSR primers were used to analyze the genetic diversity of these materials. The objective was to illustrate the necessity of collecting wild soybean materials from the place where soybean had been collected before. 62 new alleles were found only to exist in the newly collected materials, and in 22 loci, the genetic diversity index of newly-collected materials was higher than the conserved germplasm. The average similarity coefficient of newly-collected materials with other ones was 0.1918. The results indicated that it was valuable to recollect wild soybeans.

Abstract:The recent research advances on erect panicle japonica varieties was summarized,and the characteristics of erect panicle japonica varieties were analysed. The growing areas of this kind of varieties indicate a trend of quick increase because its yield potential was high and the resistance to diseases and lodging were strong, it was necessary to carry out more researches on yield-related physiology and high quality related cultivation methods.

Abstract:In this article, the progress of studies on mensurement, genetics and breeding, genetic engineering of iron content in rice seeds, is summarized. Some suggestions on research and utilization of how to increase iron content in rice seeds have been put forward in the future.

Abstract:Agricultural pests have caused serious economic damage to production and quality of crops. The use of crops resistant to pests is the most economic and efficient measure in controlling pests. Germplasm resources resistant to pests is the base of breeding resistant varieties. At present, studies on crop germplasm resources resistant to pests included collecting, identification, evaluation, preservation, utilization of resistant accessions and germplasm enhancement which promote the discovery and utilization of resistance genes and breeding of resistant varieties.

Abstract:Reducing seed water content to an optimum level is an important factor in maintaining viability during long-term storage. The National Crop Genebank has established a safe and effective seed drying procedure through the last two decades' continual trial and improvement, and has completed the drying of more than 330,000 accessions of germplasm resources. In this article, the equipments and facilities of the drying procedure, optimum drying temperature, relative humidity, drying times and its use are introduced.

Abstract:Through introduction of the activities in exploration, collecting, propagation, evaluation and documentation, ex-situ and in-situ conservation of wild rice resources in China, this paper reviewed the abundant genetic diversity and main achievements in the area of wild rice germplasm resources. Based on the analysis of existing problems, the main objectives and tasks for carrying out studies on wild rice germplasm resources in near future were provided.

Abstract:DNA polymorphism is the basis of plant diversity. In this paper, factors affecting DNA polymorphism were reviewed. In addition, the applied fields of DNA polymorphism such as gene location, gene cloning and gene function analysis are discussed. It has demonstrated a bright prospect for applications of DNA polymorphism in plant functional genomics.