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Host genetic resistance is the most effective and sustainable means of managing tan spot or yellow spot of wheat. The disease is becoming increasingly problematic due to the adoption of minimum tillage practices, evolution of effector‐mediated pathogenicity, and widespread cultivation of susceptible cultivars from a narrow genetic base. This highlights the importance of broadening the diversity of resistance factors in modern breeding germplasm. This study explored 300 genetically diverse wheat accessions, originally sourced from the N. I. Vavilov Institute of Plant Genetic Resources (VIR), St Petersburg, Russia. The collection was screened for resistance to tan spot at seedling and adult stage under controlled conditions, and in the field across 2 years. The phenotypic datasets, coupled with ToxA bioassay screening, identified a number of accessions with useful sources of resistance. Seedling disease response corresponded well with ToxA sensitivity (r = 0.49, P < 0.000), but not adult responses (r = −0.02 to −0.19, P < 0.002), and overall reactions to ToxA appeared to show poor correspondence with disease response at the adult stage. ToxA‐insensitive accessions were generally found resistant across different growth stages (all‐stage resistance, ASR) in all experiments (seedling and adult stage under controlled conditions and field). ToxA‐sensitive accessions that were susceptible at seedling stage, but resistant at both adult‐plant stages, were deemed to carry adult‐plant resistance (APR). This study provides detailed information on the degree of tan spot resistance in the Vavilov wheat collection and discusses strategies to harness these sources to boost the diversity of resistance factors in modern wheat breeding germplasm. [ABSTRACT FROM AUTHOR]

Cold temperature stress at the reproductive stage, particularly at booting and flowering stages can cause significant reductions in rice (Oryza sativa L.) yield particularly at high latitudes and elevation. Although genotypic variation for cold tolerance is known to exist, the tolerance mechanisms and genotypic consistency across the stages are yet to be understood for segregating populations. Three experiments were conducted under controlled temperature glasshouse conditions to determine floral characteristics that were associated with cold tolerance at the flowering stage and to determine genotypic consistency at the booting and flowering stages. Twenty F5 Reiziq × Lijiangheigu lines from two extreme phenotypic bulks selected for cold tolerance at booting stage in the F2 generation were utilised. Spikelet sterility under cold stress at booting was significantly correlated with spikelet sterility under cold stress at flowering (r = 0.62**) with five lines identified as cold tolerant across reproductive stages. There was also a positive correlation (r = 0.47*) between spikelet sterility under cold stress at booting at the F5 and at the F2 generation. The quantitative trait loci (QTL; qLTSPKST10.1) previously identified on chromosome 10 contributing to spikelet sterility within the F2 generation, was also identified in the F5 generation. Additionally, genomic regions displaying significant segregation between the progenies contrasting for their cold tolerance response phenotype were identified on chromosomes 5 and 7 with Lijiangheigu as allelic donor and an estimated reduction in spikelet sterility of 25% and 27%, respectively. Although genotypic variation in spikelet sterility at the booting stage was not related to the development rate for heading or flowering, those cold-tolerant genotypes at the flowering stage were the quickest to complete flowering. Cold-tolerant genotypes at the flowering stage had larger numbers of dehisced anthers and subsequently pollen number on stigma, which contributed to reduced spikelet sterility. It is concluded that enhanced anther dehiscence plays a significant role in improved cold tolerance at the flowering stage. [ABSTRACT FROM AUTHOR]

Ethiopia is believed to be the centre of origin and domestication for sorghum, where sorghum remains one of the main staple crops. Loss of biodiversity is occurring at an alarming rate in Ethiopia and crops, including sorghum, have long been recognized as vulnerable to genetic erosion. A major collection of sorghum germplasm was made in 1973 by Gebrekidan and Ejeta from north-eastern Ethiopia. A new collection of landraces was made in 2003, and these were field evaluated at Sirinka in 2004 along with representative samples from the 1973 collection. Farmer surveys and soil and climate surveys were also performed. Preliminary analysis demonstrated that some important landraces have disappeared either locally or regionally in the past 30 years and many other landraces have become marginalized. Landraces which are less preferred in terms of agronomic value and end use, and introductions, have become increasingly important. Late maturing landraces were found to be particularly vulnerable, with a number disappearing altogether. Farmers have become more risk averse, and factors such as declining soil fertility, more frequent drought and unreliable rainfall, and increased pest infestation have contributed to a change in farmer landrace selection. Data are presented on the variability and unique characters of some of the Ethiopian landraces, and implications for conservation are discussed. [ABSTRACT FROM PUBLISHER]

Ergot (caused predominantly by Claviceps africana Freder., Mantle & De Milliano) is a disease of sorghum (Sorghum bicolor L. Moench), with pollen traits reported to be associated with resistance. This study investigated the genetic architecture and the role of pollen quantity (PQ) and pollen viability (PV) in ergot resistance in an F5 recombinant inbred line (RIL) sorghum population developed from the cross between an elite germplasm line, 31945-2-2 from Australia, and a recently reported putatively resistance source line, IS8525. Percentage ergot infection (PCERGOT) in IS8525 was very low, while in contrast, 31945-2-2 was heavily infected at all inoculation dates of the two field trials conducted under artificial epiphytotic conditions during 2001 and 2002. The distribution of the predicted means for PCERGOT, PQ, and PV was normal, suggesting that the traits are polygenic in nature. Genetic correlations between the two pollen traits and PCERGOT were moderately negative, indicating that there might be some common genetic factors controlling these traits. However, low R² values of PQ (11%) and PV (9%) suggest that only a small part of the total variability in ergot resistance in this population was due to the variability in PQ and PV. Correlations between ergot scores for different sampling dates (SDATEs) and years were moderate to high, indicating relatively low levels of genotype X environment interaction. Genetic variance and broad sense heritability were also high, indicating that ergot resistance is likely to respond well to conventional selection. [ABSTRACT FROM AUTHOR]

The inheritance of resistance to root-lesion nematode was investigated in five synthetic hexaploid wheat lines and two bread wheat lines using a half-diallel design of F1 and F2 crosses. The combining ability of resistance genes in the synthetic hexaploid wheat lines was compared with the performance of the bread wheat line ‘GS50a’, the source of resistance to Pratylenchus thornei used in Australian wheat breeding programmes. Replicated glasshouse trials identified P. thornei resistance as polygenic and additive in gene action. General combining ability (GCA) of the parents was more important than specific combining ability (SCA) effects in the inheritance of P. thornei resistance in both F1 and F2 populations. The synthetic hexaploid wheat line ‘CPI133872’ was identified as the best general combiner, however, all five synthetic hexaploid wheat lines possessed better GCA than ‘GS50a’. The synthetic hexaploid wheat lines contain novel sources of P. thornei resistance that will provide alternative and more effective sources of resistance to be utilized in wheat breeding programmes. [ABSTRACT FROM AUTHOR]

A linkage map of Lablab purpureus consisting of 127 RFLP and 91 RAPD loci was constructed in an F2 population of 119 individuals. This population was derived from a cross between ’Rongai’ (an annual cultivar) and CPI 24973 (a perennial wild accession). The map comprises 17 linkage groups and covers 1610 centiMorgans (cM) with an average distance of 7 cM between markers. Severe segregation distortions were observed, with the very extreme situation where no paternal type was recovered from the mapping population. These results strongly suggest the presence of a gene conferring preferential transmission from the maternal parent ’Rongai’. It was also clear that, while the majority of RAPD markers are valuable when used together with RFLP or other stringent marker systems, they could be problematic when used solely in mapping exercises. [ABSTRACT FROM AUTHOR]

Plants were regenerated from leaf-derived callus cultures of five genotypes of Stylosanthes guianensis. There were substantial genotypic differences in morphogenetic potential, ranging from 95-100 % cv. `Graham' calli to less than 1 % of cv. `Oxley' calli forming shoots. A total of 1024 regenerants (SC1) were planted out, with 28.1 % surviving to set seed. Variant characters including albinism, reduced fertility, dwarfism and leaf morphology were observed. Variation in selfed progeny (SC2) of 138 SC1 plants was assessed in a replicated field trial involving 2484 SC2 individuals. Variant phenotypes were observed in 55 (39.9 %) SC2 famiIies. Many families were segregating for albinism, altered morphology or reduced fertility. Thirty families had lower yields than their parent and earlier and later flowering variants were found. Eight tetraploid families were identified. These were characterized by more erect habit, larger leaves, stems, flowers and seeds. reduced fertility and yield and a tendency to flower later. [ABSTRACT FROM AUTHOR]

Carica papaya, C. cauliflora and interspecific hybrids of these species were screened for resistance to two Australian isolates (338. 445) of papaya ringspot virus-type P (PRSV-P). Plants were manually inoculated with PRSV-P in the glasshouse and the reaction assessed 30 days later by back-inoculation to susceptible Cucurbita pepo and by a plate-trapped antigen-enzyme linked immunosorbent assay (PTA-ELISA). Both parents and interspecific hybrids were also planted adjacent to infected C. papaya and 30 days later tested for PRSV-P by PTA-ELISA. All interspecific hybrid and C cauliflora plants manually inoculated in the glasshouse or planted in the field failed to become infected, whereas C. papaya plants, in both situations, were infected by PRSV-P. In addition, the surviving interspecific hybrid and C. cauliflora plants tested negative, while all C. papaya plants were positive for PRSV-P in both the back-inoculation and PTA-ELISA tests. Thus, the interspecific hybrid and C. cauliflora plants were resistant to the Australian PRSV-P isolates. [ABSTRACT FROM AUTHOR]

Premise of the study : Microsatellite loci were developed to characterize genetic variation and population subdivision in Khaya senegalensis (Desr.) A. Juss. (Meliaceae). Methods and Results : Microsatellite loci were identifi ed from genomic DNA sequences generated using the 454 GS-FLX titanium platform. Primers were designed for 67 tri- and tetranucleotide repeats, of which 20 were selected for 2 multiplexes based on amplifi cation success and band size. Eleven of these loci showed polymorphism in two populations of Khaya senegalensis and amplifi ed in individuals from across the species range. Conclusions : These new microsatellite loci will be useful for investigation of the evolutionary and conservation genetics of Khaya senegalensis . [ABSTRACT FROM AUTHOR]

The importance of grass pollen to the global burden of allergic respiratory disease is well established but exposure to subtropical and temperate pollens is difficult to discern. Current monitoring of airborne pollen relies on light microscopy, limiting identification of taxa to family level. This informs seasonal fluctuations in pollen aerobiology but restricts analysis of aerobiological composition. We aimed to test the utility of DNA metabarcoding to identify specific taxa contributing to the aerobiome of environmental air samples, using routine pollen and spore monitoring equipment, as well as assess temporal variation of Poaceae pollen across an entire season. Airborne pollen concentrations were determined by light microscopy over two pollen seasons in the subtropical city of Brisbane (27°32'S, 153°00E), Australia. Thirty daily pollen samples were subjected to high throughput sequencing of the plastid rbcL amplicon. Amplicons corresponded to plants observed in the local biogeographical region with up to 3238 different operational taxonomic units (OTU) detected. The aerobiome sequencing data frequently identified pollen to genus levels with significant quantitative differences in aerobiome diversity between the months and seasons detected. Moreover, multiple peaks of Chloridoideae and Panicoideae pollen were evident over the collection period confirming these grasses as the dominant Poaceae pollen source across the season. Targeted high throughput sequencing of routinely collected airborne pollen samples appears to offer utility to track temporal changes in the aerobiome and shifts in pollen exposure. Precise identification of the composition and temporal distributions of airborne pollen is important for tracking biodiversity and for management of allergic respiratory disease., Competing Interests: Declaration of competing interest The authors declare outside the scope of this research, Davies leads the NHMRC AusPollen Partnership Project (GNT 1116107) with matching cash and in kind co-sponsorship from The Australasian Society for Clinical Immunology and Allergy, Asthma Australia, Bureau of Meteorology, Commonwealth Scientific and Industrial Research Organisation, Stallergenes Australia, Federal Office of Meteorology and Climatology MeteoSwiss, Switzerland. Davies is an investigator of current National Foundation for Medical Research Innovation grant with co-sponsorship from Abionic Switzerland. She is an inventor on patents assigned to QUT. Her institute has received Honorarium payments and travel expenses for education sessions and conference presentations from Stallergenes Australia and Wymedical in the last five years., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The distinction between native and introduced flora within isolated land masses presents unique challenges. The geological and colonisation history of Australia, the world's largest island, makes it a valuable system for studying species endemism, introduction, and phylogeny. Using this strategy we investigated Australian cosmopolitan grasses belonging to the genus Cynodon. While it is believed that seven species of Cynodon are present in Australia, no genetic analyses have investigated the origin, diversity and phylogenetic history of Cynodon within Australia. To address this gap, 147 samples (92 from across Australia and 55 representing global distribution) were sequenced for a total of 3336bp of chloroplast DNA spanning six genes. Data showed the presence of at least six putatively introduced Cynodon species (C. transvaalensis, C. incompletus, C. hirsutus, C. radiatus, C. plectostachyus and C. dactylon) in Australia and suggested multiple recent introductions. C. plectostachyus, a species often confused with C. nlemfuensis, was not previously considered to be present in Australia. Most significantly, we identified two common haplotypes that formed a monophyletic clade diverging from previously identified Cynodon species. We hypothesise that these two haplotypes may represent a previously undescribed species of Cynodon. We provide further evidence that two Australian native species, Brachyachne tenella and B. convergens belong in the genus Cynodon and, therefore, argue for the taxonomic revision of the genus Cynodon., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Heterosis is an important component of hybrid yield performance. Identifying high yielding hybrids is expensive and involves testing large numbers of hybrid combinations in multi-environment trials. Molecular marker diversity has been proposed as a more efficient method of selecting superior combinations. The aim of this study was to investigate the value of molecular marker-based distance information to identify high yielding grain sorghum hybrids in Australia. Data from 48 trials were used to produce hybrid performance-estimates for four traits (yield, height, maturity and stay green) for 162 hybrid combinations derived from 70 inbred parent lines. Each line was screened with 113 mapped RFLP markers. The Rogers distances between the parents of each hybrid were calculated from the marker information on a genome basis and individually for each of the ten linkage groups of sorghum. Some of the inbred parents were related so the hybrids were classified into 75 groups with each group containing individual hybrids that showed similar patterns of Rogers distances across linkage groups. Correlations between hybrid-group performance and hybrid-group Rogers distances were calculated. A significant correlation was observed between whole genome-based Rogers distance and yield ( r = 0.42). This association is too weak to be of value for identifying superior hybrid combinations. One reason for the generally poor association between parental genetic diversity and yield may be that important QTLs influencing heterosis are located in particular chromosome regions and not distributed evenly over the genome. Variation in the sign and magnitude of correlations between Rogers distance and hybrid-group performance for particular linkage groups observed in this study support this hypothesis. The concept of using diversity on individual linkage groups to predict performance was explored. Using data from just two linkage groups 38% of the variation in hybrid performance for grain yield could be explained. A model combining phenotypic trait data and parental diversity on particular linkage groups explained 71% of the variation in grain yield and has potential for use in the selection of heterotic hybrids.

Microsatellites or simple sequence repeats (SSRs) are ubiquitous in eukaryotic genomes. Single-locus SSR markers have been developed for a number of species, although there is a major bottleneck in developing SSR markers whereby flanking sequences must be known to design 5'-anchors for polymerase chain reaction (PCR) primers. Inter SSR (ISSR) fingerprinting was developed such that no sequence knowledge was required. Primers based on a repeat sequence, such as (CA)n, can be made with a degenerate 3'-anchor, such as (CA)8RG or (AGC)6TY. The resultant PCR reaction amplifies the sequence between two SSRs, yielding a multilocus marker system useful for fingerprinting, diversity analysis and genome mapping. PCR products are radiolabelled with 32P or 33P via end-labelling or PCR incorporation, and separated on a polyacrylamide sequencing gel prior to autoradiographic visualisation. A typical reaction yields 20-100 bands per lane depending on the species and primer. We have used ISSR fingerprinting in a number of plant species, and report here some results on two important tropical species, sorghum and banana. Previous investigators have demonstrated that ISSR analysis usually detects a higher level of polymorphism than that detected with restriction fragment length polymorphism (RFLP) or random amplified polymorphic DNA (RAPD) analyses. Our data indicate that this is not a result of greater polymorphism genetically, but rather technical reasons related to the detection methodology used for ISSR analysis.

A RAPD marker specific to the dwarf off-type (hereafter known as dwarf) from micropropagation of Cavendish banana (Musa spp. AAA) cultivars New Guinea Cavendish and Williams was identified following an analysis of 57 normal (true-to-type) and 59 dwarf plants generated from several different micropropagation events. Sixty-six random decamer primers were used in the initial screen, of which 19 (28.8%) revealed polymorphisms between normal and dwarf plants. Primer OPJ-04 (5'-CCGAACACGG-3') was found to amplify an approx. 1.5 kb band which was consistently present in all normal but absent in all dwarf plants of both cultivars. Reliable detection of dwarf plants was achieved using this marker, providing the only available means ofin vitro detection of dwarfs. The use of this marker could facilitate early detection and elimination of dwarfs from batches of micropropagated bananas, and may be a useful tool in determining what factors in the tissue culture process lead to this off type production.Other micropropagation-induced RAPD polymorphisms were observed but were not associated with the dwarf trait.

Finger millet (Eleusine coracana), an allotetraploid cereal, is widely cultivated in the arid and semiarid regions of the world. Three DNA marker techniques, restriction fragment length polymorphism (RFLP), randomly amplified polymorphic DNA (RAPD), and inter simple sequence repeat amplification (ISSR), were employed to analyze 22 accessions belonging to 5 species of Eleusine. An 8 probe--3 enzyme RFLP combination, 18 RAPD primers, and 6 ISSR primers, respectively, revealed 14, 10, and 26% polymorphism in 17 accessions of E. coracana from Africa and Asia. These results indicated a very low level of DNA sequence variability in the finger millets but did allow each line to be distinguished. The different Eleusine species could be easily identified by DNA marker technology and the 16% intraspecific polymorphism exhibited by the two analyzed accessions of E. floccifolia suggested a much higher level of diversity in this species than in E. coracana. Between species, E. coracana and E. indica shared the most markers, while E. indica and E. tristachya shared a considerable number of markers, indicating that these three species form a close genetic assemblage within the Eleusine. Eleusine floccifolia and E. compressa were found to be the most divergent among the species examined. Comparison of RFLP, RAPD, and ISSR technologies, in terms of the quantity and quality of data output, indicated that ISSRs are particularly promising for the analysis of plant genome diversity.

The Medical Society of Virginia's new database revealed 1) an aging membership with a high percentage of dues exemptions; 2) an apparent reluctance on the part of many young physicians to consider MSV dues a worthwhile investment; and 3) a marked underrepresentation in the MSV membership of women, who now comprise nearly half of most medical school classes. In order to maintain a viable organization, the Medical Society of Virginia must do more to attract those who are underrepresented in the membership. This is not a choice. It is an imperative.

Pediatric reference ranges were obtained for vitamin B12 and folate (Quantaphase radioimmunoassay, BioRad, Hercules, Calif) using a large hospital population. Data were analyzed employing the Hoffman approach, which was computer adapted. For folic acid, the range for subjects aged 1 to 12 years averaged 5.7 to 31.3 nmol/L for female subjects and 4.5 to 27.0 nmol/L for male subjects. There was a significant decrease in folic acid concentrations after 13 years, the upper limit being 16.5 nmol/L in female subjects and 19.9 nmol/L in male subjects. For vitamin B12, the values in the 0- to 1-year age group were nearly double those in the 13- to 18-year age group. For female subjects, the values in the 0- to 1-year age group were 168 to 1116 pmol/L and in male subjects were 216 to 891 pmol/L. At 13 to 18 years, for female subjects the values were 158 to 637 pmol/L and for male subjects, 134 to 605 pmol/L.

The National Cholesterol Education Program has begun a National Campaign to screen millions of adult Americans for serum cholesterol. To determine whether such random samples represent an individual's true lipoprotein status, we measured fasting total serum cholesterol and lipoproteins, on a weekly basis for 4 weeks, in 20 subjects ages 22 to 63 years. Duplicate samples were tested by two standardized laboratories, each on five consecutive days. Variations of more than +/- 20% in the serum levels of total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were seen in 75%, 95%, and 65% of the subjects, respectively. On retesting, 40% of the subjects moved in or out of one "risk category"; and in 10% two categories, from "desirable" to "high risk," or vice versa. These data demonstrate that random testing may fall to detect wide fluctuations in the levels of serum lipoproteins, and therefore result in erroneous risk assignment or therapeutic intervention.