Genetic Diversity of Chinese Temperate and Exotic Tropical, Subtropical Quality Protein Maize Inbreds by SSR Markers

Information on genetic relationship is of great value to maize (Zea mays L.) breeding. Theobjectives of this study were: 1) to classify 22 quality protein maize (QPM) inbreds intodifferent groups by using simple sequence repeats (SSR) markers, which included exotictropical, subtropical and domestic temperate QPM and normal maize inbreds; 2) to examine theconsistency of grouping results obtained from SSR, specific combining ability (SCA) analysis,and genetic backgrounds of these inbreds. A set of 39 polymorphic SSR primers was selected from70 primer pairs, which detected 136 alleles among the 22 lines. The mean polymorphisminformation content was 0.55. Based on analysis of genetic similarities, five groups wereidentified including Luda Red Cob, Sipingtou, Reid, Lancaster and a miscellaneous group withseveral tropical inbreds which could not be classified into the above four groups. The resultsgenerally agreed with previous results based on analysis of yield combining ability andpedigree data.

Pedigree and Germplasm Base of Inbreds of the Tangshan Sipingtou Heterotic Group of Maize in China

The Tangshan Sipingtou (TSSPT) germplasm in inbreds of the Tangshan Sipingtou heterotic group of maize in China was mainly derived from Huangzao4, and the source of TSSPT germplasm was severely restricted by the inbred Tangsipingtou. Except Tangsipingtou, the contents of TSSPT germplasm were only 50% or less in inbreds of this group, with the existence of more than 20 non-TSSPT gennplasms which resulted in abundant genetic diversity in this group. 95.22% inbreds of this group contained both TSSPT and UNS(unknown source) gennplasms in the ratio of 1 :1, with 12. 5 - 50% of each germplasm. The recombination of TSSPT and UNS germplasms had produced Huangzao4, the most important maize germplasm of compact plant form. About 90. 24% of the inbreds in this group were the inbred Huangzao4 and its derivatives. 11.11% of the derivatives contained 25 - 50% of Luda Honggu(LDHG) germplasm, and 16.67% of the derivatives contained 12. 5 - 25% Creole and 6. 25 -28.13% LSC germplasms. In addition, 97. 56% of the inbreds of this group contained one or more non-TSSPT germplasms. This indicates that the germplasm base of inbreds of the TSSPT heterotic group had changed and evolved away from actual TSSPT germplasm.

Pedigree and Germplasm Base of Inbreds of the Lancaster Heterotic Group of Maize in China

Lancaster Surecrop (LSC) germplasm in inbreds of the Lancaster heterotic group in China was mainly provided by the two inbreds Mol7 and Oh43. Furthermore, the source of LSC germplasm was severely restricted in two inbreds, C103 and Oh40B. The contents of LSC germplasm are 50% or less in inbreds of the group, with the existence of more than 20 non-LSC germplasms that results in the abundant genetic diversity in the group. Most inbreds of Mol7 subgroup contain 25% - 50% LSC, 12.5% - 25% Reid Yellow Dent (RYD) and 12.5%- 25% Iowa Goldmine germplasms in the ratio of 2:1:1, and most inbreds of Zi330 subgroup contain 12.5% - 25% LSC, 6.25% - 12.5% RYD, 6.25% - 12.5% Minnesota # 13 and 25% - 50% Creole germplasms in the ratio of 2:1:1 4. AH the facts indicated that the germplasm base of the Lancaster heterotic group has stupendously changed and evolved away from actual LSC germplasm.

Study of Yield Combining Ability and Genetic Relationship Among Exotic Tropical,Subtropical Maize(Zea mays L.) Inbreds and Temperate Maize Inbreds in China

Information on the genetic relationship between tropical maize (Zea mays L), germplasm and temperate maize germplasm is of great value to maize breeding. The objective of this study was to determine the combining ability and genetic relationship of 25 inbreds extracted from five tropical maize populations and a land race, with four temperate maize inbreds (Huangzaosi, Mol7, B73 and Dan 340). The 25 tropical inbreds were crossed with the four temperate inbreds and evaluated. Lines from Suwanl and POP28 had high general combining ability (GCA) for grain yield. The lines from POP32 (ETO) had the highest special combining ability (SCA) with B73; the average SCA value of the 5 lines was 879 kg/ha. The lines from Suwanl had the second-highest SCA (584 kg/ha) with Huangzaosi. The lines from Suwanl had the greatest relative heterosis (20%) with B73, followed by the lines from POP32 (ETO) with B73 (19%). Five heterotic patterns have been identified from this study: Suwanl × Reid, ETO × Reid, POP28× Reid, POP28× Ludahong-gu, and Suwan1× Lancaster.

Dissection of two QTL clusters underlying yield-related heterosis in the cabbage founder parent 01–20

Cabbage has significant heterosis and most commercial cultivars are hybrids.To explore genetic basis of cabbage heterosis and promote cabbage heterosis utilization,we constructed two populations by crossing 100 DH lines derived from a cabbage hybrid 01–20×96–100 with two female parents.Hybrids exhibited different extents of heterosis,the mean value of economic yield was 2.6 times bigger than parents.We identified 66 and 73 QTLs associated with mid-parent heterosis and transgressive heterosis of twelve yield-related traits,respectively.Some QTLs could be detected under the two-year experiment existed in two populations with different testers,showing relatively high phenotypic contribution rate(15.8%–20.0%).Heterosis QTLs exhibited clustered distribution in several cabbage chromosome regions.Two dominant genetic regions,mk300–316 and mk258–268,originated from the elite parent 01–20,exhibited significant genetic effects for yield-related heterosis,which were first identified.Three elite DH lines(D22,D46,D83)harboring these two dominant regions were selected as having strong heterosis in cabbage production.Candidate gene analysis revealed that some genes participating in biosynthetic processes of carbohydrates and some responses to auxin might affect cabbage yield heterosis.QTL identification and genetic dissection of yield-related traits provide new insights into the genetic effects of cabbage heterosis.

Screening for urinary markers predicting hematopoietic stem cell injury induced by busulfan using genetically diverse mice

Background:Busulfan(BU)is an alkylating agent used as a conditioning agent prior to hematopoietic stem cell(HSC)transplantation as it is known to be cytotoxic to host hematopoietic stem and progenitor cells.The susceptibility of HSCs to BU injury plays an important role in the myeloablative efficacy of BU.Different susceptibilities were demonstrated in genetically diverse(GD)mice in our preliminary research.Methods:Three strains of GD mice with different susceptibilities to BU-i nduced HSC injury were used for screening biological markers of HSC injury susceptibility in urine.The urine proteins were analyzed using liquid chromatography coupled with tandem mass spectrometry to screen for differentially expressed proteins.Screening for possible biomarkers based on differences in protein expression abundance was validated using enzyme-l inked immunoassay(ELISA).Results:Functional analysis showed that the differential proteins were all involved in a series of biological pathways related to cellular senescence,apoptosis,and angiogenesis;whereas the differential proteins of the high-susceptible strain were enriched for the regulation of bone marrow microenvironment pathways,those of low-susceptible strain were enriched for the proapoptotic effect of GTPase pathways.Based on protein abundance differences,several urinary proteins that may be indicative of susceptibility were screened,and ELISA validation results showed that angiotensin-converting enzyme may be a potential biomarker predicting HSC susceptibility for BU conditioning.Conclusions:This study indicates that urinary protein levels can reflect differences in susceptibility to BU-i nduced HSC injury.Using GD mice to construct genetic difference models will provide preclinical data for screening BU-related biological markers.

QTL Mapping of Yield and Yield Components for Elite Hybrid Derived-RILs in Upland Cotton

A population of 180 recombinant inbred lines （RILs） was developed by single seed descended from the cross of high yield Upland cotton （Gossypium hirsutum L.） varieties Zhongmiansuo12 （ZMSI2） and 8891, the two parents of Xiangzamian2 （XZM2）. A genetic linkage map consisting of 132 loci and covering 865.20 cM was constructed using the RIL population chiefly with SSR markers. Yield and yield components were investigated for RILs in three environments in China. The purpose of the present research was to analyze the relationship between yield and its components and to map QTL for yield and yield components in cotton. QTL were tagged with data sets from single environment （separate analysis） and a set of data from means of the three environments （joint analysis）. A total of 34 QTL for yield and yield components were independently detected in three environments, whereas fifteen QTL were found in joint analysis. Notably, a stable lint percentage QTL qLP-A10-1 was detected both in joint analysis and in two environments of separate analysis, which might be of special value for marker-assisted selection. The QTL detected in the present study provide new information on improving yield and yield components. Results of path analysis showed that bolls/plant had the largest contribution to lint yield, which is consistent with the mid-parent heterosis value in F1. Accordingly, in cotton breeding, bolls/plant can be considered first and other yield components measured as a whole to implement variety enhancement and hybrid selection of cotton.

Analysis of Resistance-related Proteins in Rice Against Brown Planthopper by Two-dimensional Electrophoresis

A recombinant inbred population (RI) was constructed from a cross between B5, an introgression. line from the wild rice Oryza officinalis Wall. ex Watt, and susceptible cultivar Minghui 63 ( O. sativa L.). The brown planthopper ( BPH) resistances of RI lines were evaluated. Based on bulked segregant analysis (BSA), two protein bulks were made by extracting proteins from equally mixed seedlings of extremely resistant and susceptible plants selected from the RI population, respectively. Two-dimensional electrophoresis was used to detect the changes of polypeptide pattern. Results showed that a protein P40 ( pI 6.3, Mw 40 kD) was significantly reduced or vanished after BPH infestation for 48 h in the susceptible bulk, while it remained uninfluenced in the resistant bulk. In connection with the physiological changes of the resistant and susceptible lines subjected to BPH sucking, we suppose that the protein P40 is related to the interaction responses of lice plants to BPH infestation.

Analyses of Protein and Oil of Maize Offsprings Plants Introducing Soybean DNA

[Objective] The experiment was aimed to explore character variation between different families after DNA introduction and select variant plants with good stability. [Method] The method of pollen-tube-pathway was used to introduce total DNA of soybean into normal maize inbred line 7313 for selecting generation by generation. When field characters of maize, grain colors, grain traits and panicle axis colors were stable, the crude protein, gliadin, glutelin and oil content of grains which were selected from variant strains were detected and compared. [Result] The grain crude protein, gliadin, glutelin and oil content of line 26h-4-3 were significantly different from these of control treatment. The increments of D3 and D4 generation were 10.34% and 26.70%, 6.58% and 6.28%, 15.09% and 70.34%, 55.82% and 51.52% respectively. All indexes of line 26h-3-1 were also higher than these of control treatment and the increments of D3 and D4 generation were 5.67% and 21.63%,1.91% and 2.31%, 10.85% and 62.27%,22.49% and 9.67%. [Conclusion] The crude protein, gliadin, glutelin and oil content of variant line 26h-4-3 and 26h-3-1 were stable, so variant line 26h-4-3 and 26h-3-1 were excellent variant strains which satisfied the requirement of high protein breeding.

Cluster Analysis of Chinese Pumpkin Inbred Lines

A cluster analysis was carried out based on Euclidean genetic distances through UPGMA method in Chinese pumpkin inbred lines.7 important agronomic traits of 46 Chinese pumpkin inbred lines were investigated.The result indicated that 46 pumpkin inbred lines were clustered into 4 groups and the inter-groups distances was larger than that in intra-group.The genetic distances of parents were related to F1 performance and the results of cluster would increase effectiveness in the Chinese pumpkin crossing breeding.

Genetic Quality Analysis of Xiphophorus helleri RR-B Strain Using 18 Microsatellite Loci

[Objective] The study aimed to further understand the genetic quality of Xiphophorus helleri RR-B strain and estimate the feasibility of microsatellite markers in genetic monitoring of aquatic laboratory animals.[Method] Eighteen microsatellite loci which had polymorphism in wild X. helleri were used for genetic quality analysis of RR-B strain (red eyes and red body) by PCR. [Result] All these 18 microsatellite loci displayed single allelic gene band in 30 individuals of X. helleri RR-B strain and the average homozygote rate reached 100%. [Conclusion] These loci could be used as markers in genetic monitoring of X. helleri RR-B strain, which had obtained fairly high genetic homozygosity by inbreeding for more than 20 generations. This study provided basic data for establishing the molecular genetic monitoring standard of aquatic laboratory animals.

Mapping QTLs for Panicle Traits Based on Rice RIL Population Derived from TD70 and Kasalath

Two hundred and forty recombinant inbred lines （RIL） derived from a cross TD70/Kasalath and its linkage map including 141 SSR markers were used to map QTLs controlling panicle length （PL）, total seeds per panicle （TSP） and grain density （GD） in 2010 and 2011. The results showed that a total of 23 QTLs controlling three panicle traits were detected on chromosomes 2, 3, 4, 6, 7, 8 and 10, respec- tively, including 5 QTLs controlling PL, 8 QTLs controlling TSP, 10 QTLs controlling GD, with the LOD value ranging between 2.5-9.3, and the QTLs explained the ob- served phenotypic by 4.0%-20.8%. The marker interval RM5699-RM424 on chro- mosome 2, RM489-RM1278 on chromosome 3, RM3367-RM1018 on chromosome 4, RM3343-RM412 on chromosome 6 were common marker intervals for TSP and GD; six QTLs （qPL3, qTSP4, qTSP6-2, qTSP7, qGD3-2 and qGDT） were detected in two years. Among these QTLs, the qPL3, qTSP6-2, qGD3-2 and qGD7 were major QTLs. All QTLs for PL mapped in the present study had been mapped QTLs previously by other research groups, 16 QTLs controlling TSP and GD were new ones which contributed the observed phenotypic variance range by 4%-9.5%. These results laid a founda^ion for further fine positioning or cloning these QTLs.

Construction of Molecular Genetic Linkage Map Based on an RIL Population of Rice and Detection of QTLs for Tiller Angle

In this study, an RIL （recombinant inbred line） population containing 240 lines was developed by single seed descent method （SSD） based on a parent com- bination of small-grain indica cultivar Kasalath and large-grain japanica cultivar TD70 with significant differences in plant type traits, to construct the molecular genetic linkage map. Totally 838 SSR （Simple Sequence Repeat） markers were used for polymorphism screening between parents, 302 SSR markers with polymorphism were detected, with a frequency of 36.04%; 141 SSR markers with clear amplified bands and uniform distribution in the genome were finally used for genotype analysis of the RIL population. According to the experimental results, the frequency of male and female genotype in this RIL population was respectively 53% and 47%, suggesting good balance in population structure. A molecular genetic linkage map of rice was constructed by 141 markers based on a RIL population of 240 lines, with a total genetic distance of about 1 832.47 cM covering all 12 chromosomes, an average genetic distance between markers of 12.70 cM and a range of genetic distance be- tween markers of 0.43-36.11 cM, which is consistent with basic requirements of quantitative trait locus （QTL） mapping. Except for few markers on chromosomes 1 and 8, the order and location of markers is similar to the published sequences of Nipponbare. QTL analysis for the tiller angle was conducted with this RIL population of 240 lines, and results showed that three QTLs controlling tiller angle were detected on chromosome 8, 9 and 11, which were named qTA8, qTA9 and qTA11, with a contribution rate of 4.10%, 26.08% and 4.35%, respectively. To be specific, qTA9 contained Tiller Angle Controlling （TAC1） gene. The construction of this molecular genetic linkage map laid the foundation for genetic analysis and QTL mapping of various traits in the progeny of indica and japonica.

经皮下注射树突状细胞治疗膀胱肿瘤的病理改变

目的观察肿瘤细胞冻融上清致敏的树突状细胞(DC)治疗膀胱肿瘤(BT)的疗效。方法选取F344大鼠44只,称重后随机分为4组,均采用膀胱灌注N-甲基亚硝基脲(MNU)制成BT;第11周4组分别经皮下注射PBS、未致敏DC、肿瘤抗原及致敏DC,每周1次,共4次;实验第15周,经电子秤、显微镜检测。结果致敏DC组大鼠体重高于其余3组,并与PBS组及未致敏DC组差异明显(P<0.05);致敏DC组膀胱重量低于其余3组且有显著性差异(P<0.05),其余各组间差异无显著性;致敏DC组病理分期明显低于PBS组和未致敏DC组(P<0.05),其余组间差别无统计学意义;致敏DC组病理分级明显低于PBS组(P<0.05),其余组间差别无统计学意义。结论应用致敏DC经皮下注射治疗大鼠膀胱肿瘤可降低肿瘤的病理分期及分级。

水稻耐淹性状QTL分析

利用籼稻品种贵9B和粳稻品种热研2号作为亲本,构建100个贵9B/热研2号重组自交系(recombinant inbred lines, RILs)家系为作图群体,进行水稻耐淹QTL检测及其遗传效应分析。以胚芽鞘长度为水稻耐淹强弱的表型数据,运用完备区间作图定位法,在第6和第9条染色体上检测到2个水稻耐淹QTL,依次命名为qGS-6-1、qGS-9-1,2个位点的LOD值分别为2.89、2.51,贡献率分别为12.03%、10.52%,qGS-6-1等位基因源于贵9B,qGS-9-1等位基因源于热研2号。该研究可为克隆控制耐淹的基因以及培育适宜直播的水稻品种提供重要的理论依据。

Combining Ability and Correlation of Ear Characteristics of Twenty Maize Inbred Lines

The combining ability and correlation of eight ear characteristics in 99 maize hybrids generated by crossing nine female parents with 11 male parents were analyzed by incomplete diallel cross （NC II ） design. The results showed that the line F6 had the highest general combining ability （GCA） for yield, followed by F7, M3, M4 and M8. All of the five lines have great potential in maize breeding. The cross combination M3xF10 had the highest specific combining ability （SCA） for yield, showing strong heterosis. Heritability analysis of ear characteristics showed that GCA variance was higher than SCA variance in ear diameter, number of rows per ear and seed rate, and they were mainly controlled by the additive gene effect, indicating that that the selections for these traits are effective at early generations. The other three traits had lower SCA, for which the selections should be carried out at late generations. The correlation analysis revealed that ear length, number of grains per row, ear diameter, number of rows per ear, 100-seed weight and seed rate had extremely significant positive correlations with grain yield per plant. Among them, number of grains per row had the most significant effect on yield per plant. Barren tip length had a significant negative correlation with grain yield per plant. Therefore, we concluded that the combinations with more grains per row and shorter barren tip should be selected to achieve high yield of maize.

Analysis on Combining Ability and Genetic Parameters of Main Agronomic Characters of 22 Maize Inbred Lines

The general combining ability（GCA）, special combining ability（SCA） and genetic parameter of ten characters of 22 maize inbred lines including plant height and ear height were analyzed using 10×12 through incomplete diallel cross（NC Ⅱ）.The results showed that：（1） Among the 22 maize inbred lines, the yield GCAs of11 HN 097, 11 HN 099, 11 HN 105 and 11 HN 110 were high, which were elite inbred lines to collocate hybridized combinations with strong heterosis. The yield of11 HN110 × 11 HN097, 11 HN110 × 11 HN105, 11 HN112 × 11 HN 097 and 11 HN 106 × 11 HN 104 were in the first four place. The yielding abilities, adaptabilities and yielding stabilities of the four combinations can be further identified by experiment. The heredities of the ten characters were mainly controlled by additive gene effect whereas the influence of non-addictive gene effect was small. The narrow heritabilities of plant height, ear height, ear rows, ear length, kernels per row,100-grain weight and seed-producing percentage were more than 50%. The variances were mainly caused by heredity and early-generation selection should be conducted. The narrow heritabilities of ear diameter, bare tip length and yield was low, which should not be selected in early-generation.

Combining Ability Analysis on Yield Traits of Recombinant Inbred Lines in Hybrid Rice

A population of 140 recombinant inbred lines at F8 generation were obtained after seven successive generations of self-pollination using single seed descent（SSD） method from the F2 hybrids of three-line restorers Luhui 8258 with high combining ability and Yanghui 34. Then, the 140 inbred lines obtained above and their parents Luhui 8258 and Yanghui 34 were crossed with three different types of cyto-plasmic male sterile（CMS） lines（Gang 46 A, Ⅱ-32 A and Lu 98A） according to NCⅡ design. The resulting 426 combinations were planted at Deyang and Suining bases to test the combining ability and inheritance of five yield traits： yield per plant, panicle number per plant, filled grain number per panicle, seed setting rate and 1 000-grain weight. The results showed that the variances of both general and specific combining abilities of the five traits all reached a significant or extremely significant level at the two sites. The broad and narrow heritability of the yield traits（except 1 000-grain weight whose broad and narrow heritability were both over70%） were all below 50% at the two experimental bases, suggesting that the four traits were easily subjected to environment influence. Very significant positive correlation of general combining ability was found between yield per plant and other traits except 1 000-grain weight. The general combining ability variance showed a normal distribution among the recombinant inbred lines at two sites, right in line with inheritance of quantitative traits. So, the genes controlling rice general combining ability can be targeted by QTL mapping.

Combining Ability Analysis of Panicle Traits in Six CIMMYT Maize Inbred Lines

In this study, six CIMMYT maize inbred lines and five representative do- mestic maize inbred lines were used as parental lines. By using incomplete diallel cross design, 30 hybrid combinations were developed to analyze the general com- bining ability （GCA）, specific combining ability （SCA） and total combining ability （TCA） of seven panicle traits in six CIMMYT maize inbred lines. The results showed that CIMBL98 and GEMS13 were excellent inbred lines with good compre- hensive performance; CIMBL98 × 340 and GEMS13×Chang 7-2 were superior combinations.

Mapping of QTLs for Dehiscence Length at Basal Part of Thecae in Rice Based on TD70/Kasalath RIL Population

A population of 240 recombinant inbred lines （RIL） was derived from a cross between Japonica rice cultivar TD70 and Indica cultivar Kasalath, and their linkage map including 141 SSR markers was used to locate the QTLs controlling the length of dehiscence at the basal part of thecae （LDBT）. Then, the correlations between LDBT and other agronomic traits of rice were analyzed. Two QTLs con- trolling LDBT were mapped on chromosome 6 and 8, respectively, qLDBT6 was mapped between RM3 and RM3628 markers on chromosome 6 with a LOD value of 3.23, contribution rate of 6.18% and additive effect of 17.74%. qLDBT8 was mapped between RM1376-RM4085 markers on chromosome 8 with a LOD value 2.95, contribution rate of 8.00% and additive effect of 20.09%. This domain probably had a relationship with the sterility of rice. The LDBT of RILs had extremely signifi- cant positive correlations with flag leaf width, 1 000-grain weight, grain width, grain length and grain thickness, but no significant correlations with other agronomic traits, such as plant height, heading date, tiller number, flag leaf length, average and the maximum temperature during heading period or rice.