Mapping QTL for bruchid resistance in rice bean (Vigna umbellata)

This research articles was published in Euphytica journal, volume 207, 2016The damage caused to stored seed by bruchids (Callosobruchus maculatus) is considered to be a major production constraint in rice bean (Vigna umbellata). Breeding for genetically determined resistance is the most environmentally benign and cost-effective means to mitigate the losses to bruchid infestation. Here, a screen of rice bean germplasm identified two sources of resistance, and determined the genetic basis of the resistance using a quantitative trait locus (QTL) mapping approach. The two resistant accessions (LRB238 and JP100304) were each crossed to a common susceptible cultivar (LRB26) to generate F2 mapping populations, one of which (LRB238 × LRB26) was genotyped with a range of Vigna sp. microsatellite assays and by sequence related amplified polymorphism (SRAP) fingerprinting. The resulting linkage map comprised ten linkage groups and covered a genetic distance of 872.1 cM with a mean inter-marker distance of 32.05 cM. The subsequent QTL analysis detected the presence of 11 QTL, distributed over all ten linkage groups, most of which were associated with the % damage caused to the seed. Two major QTL, Cmpd1.5 (flanked by the SRAP markers E2M9-270 and E12M7-311) and Cmpd1.6 (flanked by the SRAP marker E7M10-141 and the microsatellite locus CEDG259) mapped within 11.9 cM and 13.0 cM of the flanking markers, respectively, accounted for, 67.3 and 77.4 % of the variance respectively, for % damaged seeds. A bulked segregation analysis carried out in the JP100304 × LRB26 population revealed that the resistance donor harboured some resistance factors not represented in LRB238

Both habitat change and local lek structure influence patterns of spatial loss and recovery in a black grouse population

The final publication is available at Springer via http://dx.doi.org/10.1007/s10144-015-0484-3Land use change is a major driver of declines in wildlife populations. Where human economic or recreational interests and wildlife share landscapes this problem is exacerbated. Changes in UK black grouse Tetrao tetrix populations are thought to have been strongly influenced by upland land use change. In a long-studied population within Perthshire, lek persistence is positively correlated with lek size, and remaining leks clustered most strongly within the landscape when the population is lowest, suggesting that there may be a demographic and/or spatial context to the reaction of the population to habitat changes. Hierarchical cluster analysis of lek locations revealed that patterns of lek occupancy when the population was declining were different to those during the later recovery period. Response curves from lek-habitat models developed using MaxEnt for periods with a declining population, low population, and recovering population were consistent across years for most habitat measures. We found evidence linking lek persistence with habitat quality changes and more leks which appeared between 1994 and 2008 were in improving habitat than those which disappeared during the same period. Generalised additive models (GAMs) identified changes in woodland and starting lek size as being important indicators of lek survival between declining and low/recovery periods. There may also have been a role for local densities in explaining recovery since the population low point. Persistence of black grouse leks was influenced by habitat, but changes in this alone did not fully account for black grouse declines. Even when surrounded by good quality habitat, leks can be susceptible to extirpation due to isolation

Impact and relationship of anterior commissure and time-dose factor on the local control of T1N0 glottic cancer treated by 6 MV photons

<p>Abstract</p> <p>Background</p> <p>To evaluate prognostic factors that may influence local control (LC) of T1N0 glottic cancer treated by primary radiotherapy (RT) with 6 MV photons.</p> <p>Methods</p> <p>We retrospectively reviewed the medical records of 433 consecutive patients with T1N0 glottic cancer treated between 1983 and 2005 by RT in our institution. All patients were treated with 6 MV photons. One hundred and seventy seven (41%) patients received 52.5 Gy in 23 fractions with 2.5 Gy/fraction, and 256 (59%) patients received 66 Gy in 33 fractions with 2 Gy/fraction.</p> <p>Results</p> <p>The median follow-up time was 10.5 years. The 10-year LC rates were 91% and 87% for T1a and T1b respectively. Multivariate analysis showed LC rate was adversely affected by poorly differentiated histology (Hazard Ratio [HR]: 7.5, <it>p </it>= 0.035); involvement of anterior commissure (HR: 2.34, <it>p </it>= 0.011); fraction size of 2.0 Gy (HR: 2.17, <it>p </it>= 0.035) and tumor biologically effective dose (BED) < 65 Gy₁₅(HR: 3.38, <it>p </it>= 0.017).</p> <p>Conclusions</p> <p>The negative impact of anterior commissure involvement could be overcome by delivering a higher tumor BED through using fraction size of > 2.0 Gy. We recommend that fraction size > 2.0 Gy should be utilized, for radiation schedules with five daily fractions each week.</p

Scenario-led habitat modelling of land use change impacts on key species

© 2015 Gearyet al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Accurate predictions of the impacts of future land use change on species of conservation concern can help to inform policy-makers and improve conservation measures. If predictions are spatially explicit, predicted consequences of likely land use changes could be accessible to land managers at a scale relevant to their working landscape. We introduce a method, based on open source software, which integrates habitat suitability modelling with scenario-building, and illustrate its use by investigating the effects of alternative land use change scenarios on landscape suitability for black grouse Tetrao tetrix. Expert opinion was used to construct five near-future (twenty years) scenarios for the 800 km 2 study site in upland Scotland. For each scenario, the cover of different land use types was altered by 5-30% from 20 random starting locations and changes in habitat suitability assessed by projecting a MaxEnt suitability model onto each simulated landscape. A scenario converting grazed land to moorland and open forestry was the most beneficial for black grouse, and 'increased grazing' (the opposite conversion) the most detrimental. Positioning of new landscape blocks was shown to be important in some situations. Increasing the area of opencanopy forestry caused a proportional decrease in suitability, but suitability gains for the 'reduced grazing' scenario were nonlinear. 'Scenario-led' landscape simulation models can be applied in assessments of the impacts of land use change both on individual species and also on diversity and community measures, or ecosystem services. A next step would be to include landscape configuration more explicitly in the simulation models, both to make them more realistic, and to examine the effects of habitat placement more thoroughly. In this example, the recommended policy would be incentives on grazing reduction to benefit black grouse

Evaluation of agro-morphological diversity in some segregating lines of cowpea (Vigna un-guiculata L. WALP)

A study was conducted to evaluate agro-morphological characteristics of some segregating lines of eight accessions of cowpea (Vigna unguiculata L. Walp.) using seeds from a first cycle generation progenies. Eight cowpea accessions [GH36841 (red), GH3684B4 (mottle brown), GH 3684B5 (mottle brown), GH3684A2 (red), GH3684C2 (red), GHUCO1BL (black), GH3684BL, (black) and GH7184BL (black with spots)] and an out group IT97K-499-35 (white) were culti-vated under field conditions. Twenty three agro-morphological traits were assessed for thirty three lines of cowpea. A dendrogram generated using 23 agro-morphological characters distinguished the cowpea accessions into two lineages, with the out-group being the most diverse. Generally, morphological polymorphism revealed discriminations among the cowpea accessions studied. Seed weight, plant height, number of branches, length of branches, number of leaves, number of peduncles, length of peduncles and number of seeds per pod as well as number of pods per plant differed significantly (p &le; 0.05) among the cowpea accessions. The evidence showed that there were variations in morphological characteristics expressed by the cowpea ac-cessions and these were segregations in one trait or the other. The cowpea accession GH UCO1BL is possibly a cross between IT97K-499-35 x SARC-LO2. The segregation lines of GH 3684 had the greatest diversity probably due to genotype environment interactions