Genomic regions associated with common root rot resistance in the barley variety Delta

Common root rot (CRR) caused by Bipolaris sorokiniana is a serious disease constraint in the dry temperate cereal growing regions of the world. Currently little is known about the genetic control of resistance to CRR in cereals. In this study based on a Delta/Lindwall barley population we have undertaken a bulked segregant analysis (BSA) and whole genome mapping approach utilising Diversity Arrays Technology (DArT) to identified quantitative trait loci (QTL) associated with CRR expression. One QTL each was identified on chromosomes 4HL and 5HL explaining 12 and 11% of the phenotypic variance, respectively

Genetic analysis of wheat rust resistance genes segregating in a Kariega x Avocet S population

Item does not contain fulltext14 mei 201

Generating sequential space-filling designs using genetic algorithms and Monte Carlo methods

In this paper, the authors compare a Monte Carlo method and an optimization-based approach using genetic algorithms for sequentially generating space-filling experimental designs. It is shown that Monte Carlo methods perform better than genetic algorithms for this specific problem

Chromosome composition in an F2 hexaploid x durum cross analysed by DArT markers and MCFISH

A major constraint to tetraploid durum wheat production in Australia is widespread susceptibility to crown rot, due to infection by Fusarium pseudograminearum

Genetic analysis of wheat rust resistance genes segregating in a Kariega x Avocet S population

Complete adult plant resistance (APR) to stripe rust of the wheat cultivar Kariega was previously ascribed to two major quantitative trait loci (QTL) on chromosomes 2B and 7D and three minor QTL. In the present study the Kariega x Avocet S doubled haploid population was increased from 150 to 254 individuals and the map improved by adding Diversity Array Technology (DArT) markers. Additional field and greenhouse phenotypic data for stripe rust were collected. The major QTL regions detected previously were validated, but different minor QTL compared to the previous study were identified. In the field, the chromosome 2B QTL region explained more of the phenotypic variance for host reaction type scores (RT), compared to the 7D QTL region. For the field leaf area infected score (LAI) both the major QTL regions explained more variance over time. A minor QTL on chromosome 4A of Kariega was consistently detected for LAI (up to 25.9%) and the two early RT (up to 12.2%) scores. In addition we used an accelerated greenhouse scoring method for APR to stripe rust, which detected both major QTL, the 4A QTL and another minor QTL. Using an adult plant screening method and different pathotypes of Puccinia triticina, several leaf rust resistance genes have been detected in the mapping population. This study has been valuable in confirming and expanding information on the leaf rust resistance genes and QTL for adult plant resistance to stripe rust in wheat

Primary beam effects of radio astronomy antennas -- II. Modelling the MeerKAT L-band beam

After a decade of design and construction, South Africa's SKA-MID precursor MeerKAT has begun its science operations. To make full use of the widefield capability of the array, it is imperative that we have an accurate model of the primary beam of its antennas. We have taken available L-band full-polarization 'astro-holographic' observations of three antennas and a generic electromagnetic simulation and created sparse representations of the beams using principal components and Zernike polynomials. The spectral behaviour of the spatial coefficients has been modelled using discrete cosine transform. We have provided the Zernike-based model over a diameter of 10 deg averaged over the beams of three antennas in an associated software tool (EIDOS) that can be useful in direction-dependent calibration and imaging. The model is more accurate for the diagonal elements of the beam Jones matrix and at lower frequencies. As we get more accurate beam measurements and simulations in the future, especially for the cross-polarization patterns, our pipeline can be used to create more accurate sparse representations of MeerKAT beams.Comment: 16 pages, 18 figures. This is a pre-copyedited, author-produced PDF of an article accepted for publication in MNRAS following peer review. The version of record [K. M. B. Asad et al., 2021] is available online at: https://doi.org/10.1093/mnras/stab10

Adaptive Multidimensional Modeling with Applications in Scientific Computing

No abstract availabl

Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation.Comment: Published in ApJ (2018 April 5); 13 pages, 4 figure