Map Distance Research Articles

IDENTIFICATION AND MAPPING OF A GENE FOR RICE SLENDER KERNEL USING Oryza glumaepatula INTROGRESSION LINES

<br />World demand for superior rice grain quality tends to increase. One of the criteria of appearance quality of rice grain is grain shape. Rice consumers exhibit wide preferences for grain shape, but most Indonesian rice consumers prefer long and slender grain. The objectives of this study were to identify and map a gene for rice slender kernel trait using Oryza glumaepatula introgression lines with O. sativa cv. Taichung 65 genetic background. A segregation analysis of BC4F2 population derived from backcrosses of a donor parent O. glumaepatula into a recurrent parent Taichung 65 showed that the slender kernel was controlled by a single recessive gene. This new identified gene was designated as sk1 (slender kernel 1). Moreover, based on the RFLP analyses using 14 RFLP markers located on chromosomes 2, 8, 9, and 10 in which the O. glumaepatula chromosomal segments were retained in BC4F2 population, the sk1 was located between RFLP markers C679 and C560 on the long arm of chromosome 2, with map distances of 2.8 and 1.5 cM, respectively. The wild rice O. glumaepatula carried a recessive allele for slender kernel. This allele may be useful in breeding of rice with slender kernel types. In addition, the development of plant materials and RFLP map associated with slender kernel in this study is the preliminary works in the effort to isolate this important grain shape gene.

A novel QTL governing resistance to stem rot disease caused by Sclerotium rolfsii in peanut

Stem rot disease caused by Sclerotium rolfsii is limiting the peanut production worldwide. Linkage analysis and QTL mapping for resistance to stem rot disease was done in a biparental F2 population developed from a susceptible cultivar GG 20 and a resistant interspecific prebreeding line CS 19 using 1980 simple sequence repeat markers. Only 25.5 % primers were found polymorphic between parents. Among polymorphic primers 23 could differentiate homozygotes and F1 heterozygotes and were carried forward for the genotyping of 178 F2 progenies. Out of which 12 primers segregated in expected 1:2:1 ratio while rest segregated in a distorted ratio. Upon comparison with the international consensus map of peanut 22 markers are found anchored markers of 20 linkages except AHS1480. In this study a total map distance of 558.74 cM is covered by 12 marker loci in two linkage groups. Here we report AHS1480 as a new marker to the existing international consensus peanut linkage map. In this studies a major QTL qstga01.1 is identified for resistance to stem rot disease in peanut which is contributed by resistant parent. Both flanking markers GM2350 and TC4H02 are tightly linked to the major QTL. To our understanding this is the first report on QTL for resistance to stem rot disease in peanut.

Potential of 13 linked autosomal short tandem repeat loci in pairwise kinship analysis.

In this study, a panel of 13 STR loci locate on chromosome 3, 4, and 17 (D3S2402, D3S2452, D3S1766, D3S4554, D3S2388, D3S3051, D3S3053, D4S2404, D4S2364, AC001348A, AC001348B, D17S975, and D17S1294) were assessed for pairwise kinship analysis. Map distances between these STR loci ranged from 0.07 cM to 97.03 cM. The population genetic study of Chinese Han population showed that linkage disequilibrium exists in two clusters of closely linked markers (D4S2404-D4S2364 and D17S975-D17S1294), in which the recombination fractions were 0.0026 and 0.0001, respectively. The recombination fractions derived from the Rutgers Map for the closely linked markers (genetic distance < 0.5 cM) were significant underestimates in comparison to those of direct observation of STR transmissions in families. When effect of linkage on pairwise kinship testing was evaluated by comparing likelihood ratio (LR) values taking linkage into account, overall LR values increased. But extremely low LRs were also observed. Finally, the power of the 13 STR loci to discriminate relationship among full-sibs, half-sibs, grandparent-grandchild, uncle-niece, and unrelated pairs was assessed with a category fraction. The results showed that about 72.64% of full-sib pairs and about 82.84% of unrelated pairs could be classified correctly. But the category fractions of second-degree relationships drastically reduced to 7.34-35.48%. If only pairs of grandparent-grandchild, half-sibs, and uncle-niece were distinguished, the category fraction was 0.5512, 0.1147, and 0.4362, respectively. Our study results demonstrated that linked STRs were helpful to differentiate the most frequent relationships in pairwise kinship analysis.

Monocular Vision-Based Localization Using ORB-SLAM with LIDAR-Aided Mapping in Real-World Robot Challenge

[abstFig src='/00280004/06.jpg' width='300' text='Monocular Visual Localization in Tsukuba Challenge 2015. Left: result of localization inside the map created by ORB-SLAM. Right: position tracking at starting point.' ] For the 2015 Tsukuba Challenge, we realized an implementation of vision-based localization based on ORB-SLAM. Our method combined mapping based on ORB-SLAM and Velodyne LIDAR SLAM, and utilized these maps in a localization process using only a monocular camera. We also apply sensor fusion method of odometer and ORB-SLAM from all maps. The combined method delivered better accuracy than the original ORB-SLAM, which suffered from scale ambiguities and map distance distortion. This paper reports on our experience when using ORB-SLAM for visual localization, and describes the difficulties encountered.

Genetic Mapping of SSR Markers in Eight Soybean Chromosomes Based on F2 Population B3462 x B3293

&lt;p&gt;Genetic Mapping of SSR Markers in Eight Soybean&lt;br /&gt;Chromosomes Based on F2 Population B3462 x B3293. I&lt;br /&gt;Made Tasma, Ahmad Warsun, Dani Satyawan, Saptowo&lt;br /&gt;J. Pardal, and Slamet. Aluminum toxicity is one of the main&lt;br /&gt;contrains for cultivating soybean in acid soils. Genetic&lt;br /&gt;Hak Cipta © 2011, BB-Biogen&lt;br /&gt;mapping of SSR markers is one step for detecting aluminumtoxicity&lt;br /&gt;tolerant QTLs in soybean. Another step is to&lt;br /&gt;phenotype the same population at various aluminum-toxicity&lt;br /&gt;environments. The objectives of this study were to analyze&lt;br /&gt;the segregation of SSR markers in progenies of an F2&lt;br /&gt;population and map the markers in 8 soybean chromosomes.&lt;br /&gt;The F2 population was previously developed by&lt;br /&gt;crossing the Al-tolerant parent B3462 and the Al-sensitive&lt;br /&gt;parent B3293. Polymorphic SSR markers in the parents were&lt;br /&gt;used to PCR amplify DNA of the 100 F2 progenies. PCR&lt;br /&gt;products were separated using agarose or polyacrylamide&lt;br /&gt;gels. A Chi-Square test was done with a null hypothesis that&lt;br /&gt;progenies segregated in a 1 : 2 : 1 ratio. Results showed that&lt;br /&gt;125 SSR markers were polymorphics in the parents. Out of&lt;br /&gt;125 polymorphic markers, 122 were segregated in the&lt;br /&gt;progenies of the F2 population. Among the segregating&lt;br /&gt;markers, 114 were segregated in a 1 : 2 : 1 ratio. Only 8&lt;br /&gt;markers (5.6%) did not follow the 1 : 2 : 1 ratio. One hundred&lt;br /&gt;and nineteen SSR markers were mapped in 8 soybean&lt;br /&gt;chromosomes. These include 18 markers in chromosome&lt;br /&gt;A2, 10 in B1, 16 (C1), 16 (F), 10 (G), 23 (J), 16 (L), and 10 (N).&lt;br /&gt;Total genetic maps covered was 1,194.8 cM with average&lt;br /&gt;map distances between two adjacent markers of 10.7 cM.&lt;br /&gt;Further SSR marker enrichment is required to fill in the gaps&lt;br /&gt;of several chromosomal regions. Genetic maps presented in&lt;br /&gt;this study should be useful for detection of Al-toxicity&lt;br /&gt;tolerant QTLs in soybean.&lt;/p&gt;

Don't Stop Believing: Mapping Distance Learners' Research Journeys

ABSTRACTJourney mapping, a method of collecting data that illustrates individuals' paths toward a specific goal, was originally developed for use in retail/customer service environments. Much of the literature describes its application in examining customer behavior when navigating merchants' Websites, allowing researchers to examine the effectiveness, user-friendliness, as well as confusing or ambiguous junctures of their Webpages referred to as “points of pain.” The research approach has been applied minimally in library environments, and exclusively to patrons' experiences in the physical, brick and mortar library. The present study aimed to gather data about distance patrons' experiences in using online library resources. Input was solicited from students in Pepperdine University's Graduate School of Education and Psychology (GSEP) and the Graziadio Graduate School of Business and Management. Springshare's LibGuide software was used to collect data.

Towards developing a genetic linkage map of isabgol ( Plantago ovata Forsk.), a medicinal plant with potent laxative properties

Genetic linkage maps facilitate the genetic dissection of complex traits and comparative analyses of genome structure, as well as molecular breeding in species of economic importance. Isabgol [ Plantago ovata (Forsk.)], a medicinal plant with potent laxative properties is used in several tradi-tional systems of Medicines and cultivated in India. We explored the DNA sequences of Isabgol in the Genbank (NCBI) and developed over 1500 simple sequence repeats (SSR) markers. Some of them were validated through DNA amplification. Transferability of SSRs from wild Plantago species viz., P. major, P. coronopus, P. lancelolata, P. maritina and P. intermida into Plantago ovata was stud-ied. We developed a genetic linkage map using recombinant inbred lines (RILs) population which comprises of 30 random amplified polymorphic DNA (RAPD) markers spreading across 11 linkage groups (PO-1 to PO-11) with a total map distance of 75.6 cM. The SSR markers developed will have applications in assessing the functional diversity, comparative mapping and other applications in isabgol.

Identification of Rare Recombinants Leads to Tightly Linked Markers for Nematode Resistance in Peanut

ABSTRACTStrong host resistance to root-knot nematode (RKN; Meloidogyne arenaria) introgressed from a wild diploid species to cultivated peanut was previously shown to be located on a large chromosomal region of linkage group A09. Little to no recombination in mapping populations has hindered fine mapping of the resistance genes. In order to further delineate the introgressed region, additional polymorphic markers were added to the linkage group A09 using a recombinant inbred line population developed from Gregory x Tifguard in which Gregory is the susceptible parent and Tifguard is the resistant parent harboring the alien introgression. Map distance within the introgressed region based on this population increased to 8 cM compared with zero recombination in an earlier generation. Lines with rare recombination within this introgressed region were phenotyped and it was demonstrated that one portion of the introgressed region confers moderate resistance while a smaller, distal portion confers strong resistance to RKN. Molecular markers associated with the introgressed region conferring strong resistance can be deployed in peanut breeding programs to improve selection for RKN resistance.

SOMEDGRA: A case retrieval method for machine tool product configuration design

Case based design is an intelligent method which involves retrieving the most similar previous case to provide a solution of a new decision problem. However, conventional case based design approaches are too reliant on experts’ experiences. A new case retrieval method SOMEDGRA that combines Self-organizing map (SOM) and Euclidean distance (ED) method as well as Grey relational analysis (GRA) method is proposed in case based design. SOM is used to reduce the retrieval range and increase the retrieval efficiency, and ED is used to evaluate the similarity of cases comprehensively. To ensure that the final case has the best overall performance, an evaluation method of similar cases based on GRA is proposed to evaluate similar cases to select the most suitable case. The case study and result on an HTC series machine tool product show that the proposed method is effective, accurate and rapid in the process of product configuration.

Development of a large number of SSR and InDel markers and construction of a high-density genetic map based on a RIL population of pepper (Capsicum annuum L.)

Capsicum annuum, the most widely cultivated species of pepper, is used worldwide for its important nutritional and medicinal values. The construction of an intraspecific high-density genetic linkage map would be of practical value for pepper breeding. However, the numbers of PCR-based simple sequence repeat (SSR) and insertion/deletion (InDel) markers that are available are limited, and there is a need to develop a saturated, intraspecific linkage map. The non-redundant Capsicum species’ expressed sequence tag (EST) database from the National Center for Biotechnology Information was used in this study to develop a total of 902 usable EST-SSR markers. Additionally, 177,587 SSR loci were identified based on the pepper genomic information, including 9182 SSR loci 500 bp both upstream and downstream of coding regions. Another 4497 stable and reliable InDel loci were also developed. From 9182 SSR and 4497 InDel loci, 3356 pairs of genomic SSR primers and 1400 pairs of InDel primers that were evenly distributed in 12 chromosomes were selected. A high-density intraspecific genetic map of C. annuum was constructed using the F10-generation recombinant inbred line of parents PM702 and FS871 as the mapping population, screening the selected 3356 pairs of genomic SSR primers and 1400 pairs of InDel primers and the 902 EST-SSR markers developed earlier, and 524 published SSR markers and 299 orthologous markers (including 263 COSII markers and 36 tomato-derived markers) used previously to develop an interspecific genetic map (C. annuum × C. frutescens). Eventually, a high-density complete genetic intraspecific linkage map of C. annuum containing 12 linkage groups and 708 molecular markers with a length of 1260.00 cM and an average map distance of 1.78 cM was produced. This intraspecific, high-density, complete genetic linkage map of C. annuum contains the largest number of SSR and InDel markers and the highest amount of saturation so far, and it will be of considerable significance for the breeding of improved cultivars of this important field crop in the future.

Random forest estimation of genomic breeding values for disease susceptibility over different disease incidences and genomic architectures in simulated cow calibration groups

A simulation study was conducted to investigate the performance of random forest (RF) and genomic BLUP (GBLUP) for genomic predictions of binary disease traits based on cow calibration groups. Training and testing sets were modified in different scenarios according to disease incidence, the quantitative-genetic background of the trait (h2=0.30 and h2=0.10), and the genomic architecture [725 quantitative trait loci (QTL) and 290 QTL, populations with high and low levels of linkage disequilibrium (LD)]. For all scenarios, 10,005 SNP (depicting a low-density 10K SNP chip) and 50,025 SNP (depicting a 50K SNP chip) were evenly spaced along 29 chromosomes. Training and testing sets included 20,000 cows (4,000 sick, 16,000 healthy, disease incidence 20%) from the last 2 generations. Initially, 4,000 sick cows were assigned to the testing set, and the remaining 16,000 healthy cows represented the training set. In the ongoing allocation schemes, the number of sick cows in the training set increased stepwise by moving 10% of the sick animals from the testing set to the training set, and vice versa. The size of the training and testing sets was kept constant. Evaluation criteria for both GBLUP and RF were the correlations between genomic breeding values and true breeding values (prediction accuracy), and the area under the receiving operating characteristic curve (AUROC). Prediction accuracy and AUROC increased for both methods and all scenarios as increasing percentages of sick cows were allocated to the training set. Highest prediction accuracies were observed for disease incidences in training sets that reflected the population disease incidence of 0.20. For this allocation scheme, the largest prediction accuracies of 0.53 for RF and of 0.51 for GBLUP, and the largest AUROC of 0.66 for RF and of 0.64 for GBLUP, were achieved using 50,025 SNP, a heritability of 0.30, and 725 QTL. Heritability decreases from 0.30 to 0.10 and QTL reduction from 725 to 290 were associated with decreasing prediction accuracy and decreasing AUROC for all scenarios. This decrease was more pronounced for RF. Also, the increase of LD had stronger effect on RF results than on GBLUP results. The highest prediction accuracy from the low LD scenario was 0.30 from RF and 0.36 from GBLUP, and increased to 0.39 for both methods in the high LD population. Random forest successfully identified important SNP in close map distance to QTL explaining a high proportion of the phenotypic trait variations.

EARTH MOVER DISTANCE SYSTEM TO DISCLOSE DOS ATTACKS

In this internet era, security is a major issue. Out of the many attacks DoS attack is one among them. Researchers have been working on it from 1990’s. Many systems were introduced to detect DoS attacks which used machine learning approaches and statistical analysis where in, in the proposed system we use anomaly based technique. The methods used for detection are Principal Component Analysis, Multivariate Correlation Analysis using Triangular Area Map and Earth Mover Distance. For reducing the features we make use of the Principal Component Analysis technique which is the dimensionality reduction algorithm. For effective detection , finding the correlation between the obtained features is important and hence we use Multivariate Correlation Analysis along with the Triangular Area Map. Out of the many known dissimilarity measures in MinKowski-form distance LP and X 2 statistics where it evaluates dissimilarity between distributions, we make use of different approache called Earth Mover Distanc(EMD) to attain the goal which gives higher accuracy. The uniqueness of EMD makes the proposed system more capable. Evaluations are conducted using KDD cup dataset.

Grey‐level context‐driven histogram equalisation

Histogram equalisation (HE), which redefines the distribution of grey-levels in image, is an important step in image processing to enhance the image quality. Until now, numerous HE techniques have been proposed, among which major numbers have focused on solving the problem of how the grey-levels in the histogram of an input image should be properly partitioned so that the image produced by collecting all equalisation results for the partitioned sub-histograms leads to the quality enhancement of image. However, the partition-based equalisation methods have an inherent limitation that it is not able to equalise a sub-histogram crossing a partition boundary, which is the main cause of image distortion. In this study, the authors propose a new HE method to overcome this limitation. Precisely, rather than constraining disjoint mapping ranges of the grey-levels among the partitions, they devise two enabling techniques: (i) a mapping range for each grey-level with no range-disjoint constraint and (ii) a mapping distance between two adjacent grey-levels to make a full exploitation of mapping flexibility of grey-levels. They embody the image's global intensity distribution of grey-levels in the first technique while they embody the image's context in the second one.

Genetic analysis and molecular mapping of seedling survival drought tolerance gene in lentil (Lens culinaris Medikus)

Lentil populations were developed from crosses between ‘JL-3’ (sensitive to drought stress) and ‘PDL-1’ and ‘FLIP-96-51’ (tolerant to drought stress), to study the inheritance of drought tolerance and to identify the markers associated with it. The parental types, F1, F2, F3, and backcross (BC) generations were screened for drought tolerance using seedling survivability and drought scores. The F1 hybrids responded similar to the drought-tolerant parent, indicating dominance of seedling drought tolerance over sensitivity. Segregation for seedling survival drought tolerance versus sensitivity in F2 generation was in complete agreement with monogenic 3:1 ratio. The F3 families and backcross data additionally confirmed monogenic tolerance based on seedling survival under drought. Out of 51 SSR markers screened, thirteen markers were polymorphic between the parental types. Seven markers among them were found to be associated with seedling survival drought tolerance through bulk segregant analysis. Association of these markers with seedling survival drought tolerance was further confirmed through their screening on 10 drought-tolerant and drought-sensitive genotypes. These seven markers were screened in F2 mapping population (JL-3 × PDL-1) of 101 individuals to map their position in relation to the gene for seedling survival drought tolerance. Linkage analysis mapped the seven markers within a map distance of 133.2 cM. A single major gene Sdt was identified with a LOD value of 19.9 and phenotypic variation (R 2) of 69.7 %. The Sdt locus was obtained in the marker interval of PLC_105–PBA_LC_1480 spanning 24.9 cM with the closest marker PLC_105 at a distance of 9.0 cM on the obtained linkage group. This is the first report on genetic control and linkage of SSR markers for drought tolerance in lentil. These linked markers can be used in molecular breeding programmes for introgression of seedling survival drought tolerance gene in high-yielding cultivars.

Identification of two major quantitative trait locus for fresh seed dormancy using the diversity arrays technology and diversity arrays technology‐seq based genetic map in Spanish‐type peanuts

AbstractSeed quality for both germination in the next generation and for human consumption is adversely affected due to preharvest sprouting in peanut. It also makes seeds more vulnerable to infection by a number of pathogens. Therefore, it is desirable to have 2–3 weeks of fresh seed dormancy (FSD) in the peanut varieties. In this context, one F2 population was developed from a cross between non‐dormant (ICGV 00350) and dormant (ICGV 97045) genotypes. Phenotyping of this population showed control of the trait by two recessive genes. In parallel, genotyping of the population with Diversity Arrays Technology (DArT) and DArT‐seq markers provided a genetic map with 1152 loci covering a map distance of 2423.12 cM and map density of 2.96 cM/loci. Quantitative trait locus (QTL) analysis identified two major QTLs, namely qfsd‐1 and qfsd‐2 explaining 22.14% and 71.21% of phenotypic variation, respectively. These QTLs, after validation in different genetic backgrounds, may be useful for molecular breeding for FSD in peanut.

QTL mapping for late leaf spot and rust resistance using an improved genetic map and extensive phenotypic data on a recombinant inbred line population in peanut (Arachis hypogaea L.)

The linkage map for the recombinant inbred line (RIL) mapping population derived from late leaf spot (LLS) and rust disease susceptible (TAG 24) and resistant (GPBD 4) varieties of peanut was improved by adding 139 new SSR and transposable element (TE) markers. The improved map now has 289 mapped loci with a total map distance of 1730.8 cM and average inter-marker distance of 6.0 cM across 20 linkage groups. Quantitative trait loci (QTL) analysis using improved genetic map with 289 markers and comprehensive phenotypic data for LLS and rust from 11 seasons could identify a region on linkage group AhXV (B03 linkage group of B genome) which contributed significantly towards LLS and rust resistance. Of the five QTL mapped in this region, three showed high phenotypic variance explained (PVE) for both LLS and rust, and two QTL showed high PVE for only rust. The QTL flanked by GM2009-IPAHM103 had very high PVE of 44.5 % and 53.7 %, respectively for LLS and rust response. Another genomic region on AhXII (B10 linkage group of B genome) contained a QTL flanked by GM1839-GM1009 which had a PVE of 14.1–35.2 % for LLS resistance. A new QTL with marker interval GM1989-AhTE0839 on AhV (A05 linkage group of A genome) showed a PVE of 10.2 % for rust resistance. The new markers, AhTE0498 and AhTE0928 linked to rust resistance were validated using another RIL population of TG 26 × GPBD 4. The marker AhTE0498 showed 49.3–52.3 % PVE, indicating a strong marker validation in the new population. The improved map, QTL and markers for LLS and rust resistance reported in this study will be of immense utility in peanut molecular breeding.

A Novel Format of Depth Map Image

When the micro lens array machined by an ultra-precision machine was used in 3D computer graphics, a novel format of depth map image was invented with adaptively variable data length for multi requirements of different 3D computer graphics applications. A depth map is an image or image channel that contains information relating to the distance of the surfaces of objects a scene from a viewpoint. Depth maps can be applied for many functions: defocusing, rendering of 3D scenes, shadow mapping and other distance information-related applications.

Linkage mapping of a polymorphic plumage locus associated with intermorph incompatibility in the Gouldian finch (Erythrura gouldiae).

Colour polymorphism is known to facilitate speciation but the genetic basis of animal pigmentation and how colour polymorphisms contribute to speciation is poorly understood. Restricted recombination may promote linkage disequilibrium between the colour locus and incompatibility genes. Genomic rearrangement and the position of relevant loci within a chromosome are important factors that influence the frequency of recombination. Therefore, it is important to know the position of the colour locus, gene order and recombination landscape of the chromosome to understand the mechanism that generates incompatibilities between morphs. Recent studies showed remarkable pre- and postzygotic incompatibilities between sympatric colour morphs of the Gouldian finch (Erythrura gouldiae), in which head feather colour is genetically determined by a single sex-linked locus, Red. We constructed a genetic map for the Z chromosome of the Gouldian finch (male-specific map distance=131 cM), using 618 captive-bred birds and 34 microsatellite markers, to investigate the extent of inter- and intraspecific genomic rearrangements and variation in recombination rate within the Z chromosome. We refined the location of the Red locus to a ~7.2-cM interval in a region with a moderate recombination rate but outside the least-recombining, putative centromeric region. There was no evidence of chromosome-wide genomic rearrangements between the chromosomes carrying the red or black alleles with the current marker resolution. This work will contribute to identifying the causal gene, which will in turn enable alternative explanations for the association between incompatibility and colouration, such as fine-scale linkage disequilibrium, genomic rearrangements and pleiotropy, to be tested.

Molecular genetic map construction and QTL analysis of fruit maturation period in grapevine.

In this study, we aimed at finding the genetic regularity of grape maturation period. Early-maturing grapevine, "87-1", was used as the female parent and late-maturing, "9-22", as the male parent, to create an F1 hybrid population. A total of 149 individual plants and their parents were selected as the mapping population. Sequence-related amplified polymorphism and simple-sequence repeat analyses were performed. We performed a linkage analysis and constructed a molecular genetic map. In the obtained map, the female and male parents each covered 19 linkage groups containing 188 and 175 maker loci, respectively. The total map distances for the female and male parents were 1074.5 and 1100.2 cM, respectively, whereas the average genetic distances between each two loci were 5.7 and 7.8 cM, respectively. The interval-mapping method was used in a quantitative trait locus (QTL) analysis for fruit maturation period. A total of 12 QTLs associated with fruit maturation period were detected. These included four QTLs in the male parent genetic map that were located in linkage groups M5, M11, M14-1, and M16, with a 62.6-75.7% rate of contribution of each QTL. Another three QTLs were found in the female parent genetic map, located in linkage groups F6, F14-1, and F18, with a 72.7-77.7% rate of contribution of each QTL. Five more QTLs were detected in the consensus map, located in linkage groups LG11, LG14-1, LG16, LG17, and LG18, with 8.9-75.7% phenotypic variance explained by each QTL.

Does a localized plasma disturbance in the ionosphere evolve to electrostatic equilibrium? Evidence to the contrary

AbstractElectrostatic equilibrium must be achieved through electromagnetic evolution. From an initial state with nonzero neutral wind localized along the geomagnetic field, and with all other plasma and electromagnetic perturbations initially zero, evolution progresses from plasma velocity to electric field to magnetic field, where the last step can launch an Alfvén wave that transmits the electromagnetic disturbance along geomagnetic field lines. Without the Alfvén wave the disturbance does not map along geomagnetic field lines, and there is no semblance of electrostatic equilibrium. This paradigm is essentially the traditional magnetosphere/ionosphere coupling paradigm, except addressed to smaller‐scale, local ionospheric phenomena. However, Alfvén waves have not been thoroughly studied in the context of the partially ionized, collisional ionospheric plasma, and so the full effects predicted by this modeling paradigm are not known. In this work we adopt the two‐fluid equations and investigate whether the ionosphere supports Alfvén‐type waves that can transmit disturbances along geomagnetic field lines and perform a wave analysis of the “lumped circuit” parameters normally used to characterize the ionosphere under electrostatic equilibrium. We find that under the wave analysis (1) the Pedersen conductivity is severely modified and has a negative real part at short wavelengths; (2) the mapping distance for electric fields is significantly modified, and there is a nonnegligible wavelength along the geomagnetic field; and (3) the load admittance seen by a localized dynamo is strongly reactive, causing a phase offset between electric field and current, as compared with that when the load is electrostatic.