28 research outputs found
Prospects for Genomic Selection in Cassava Breeding
Article purchased; Published online: 28 Sept 2017Cassava (Manihot esculenta Crantz) is a clonally propagated staple food crop in the tropics. Genomic selection (GS) has been implemented at three breeding institutions in Africa to reduce cycle times. Initial studies provided promising estimates of predictive abilities. Here, we expand on previous analyses by assessing the accuracy of seven prediction models for seven traits in three prediction scenarios: cross-validation within populations, cross-population prediction and cross-generation prediction. We also evaluated the impact of increasing the training population (TP) size by phenotyping progenies selected either at random or with a genetic algorithm. Cross-validation results were mostly consistent across programs, with nonadditive models predicting of 10% better on average. Cross-population accuracy was generally low (mean = 0.18) but prediction of cassava mosaic disease increased up to 57% in one Nigerian population when data from another related population were combined. Accuracy across generations was poorer than within-generation accuracy, as expected, but accuracy for dry matter content and mosaic disease severity should be sufficient for rapid-cycling GS. Selection of a prediction model made some difference across generations, but increasing TP size was more important. With a genetic algorithm, selection of one-third of progeny could achieve an accuracy equivalent to phenotyping all progeny. We are in the early stages of GS for this crop but the results are promising for some traits. General guidelines that are emerging are that TPs need to continue to grow but phenotyping can be done on a cleverly selected subset of individuals, reducing the overall phenotyping burden
Ação de reguladores vegetais no crescimento de tomateiro (Lycopersicon esculentum Mill. cv. «Miguel Pereira»)
This research deals with the effects of exogenous growth regulators on development of the tomato cultivar «Miguel Pereira». Observations of tomato plants treated with (2-chloroethyl) trimethylammonium chloride (2,000 ppm) and succinic acid -2,2-d:methyi-hydrazide (3,000 ppm) showed that growth regulators induced little variation in plant height. Gibberellic acid (100 ppm) caused greater variation in height.Estudaram-se em condiçÔes de casa de vegetação, os efeitos da aplicação de reguladores vegetais no crescimento do tomateiro cultivar "Miguel Pereira". AlĂ©m do tratamento controle, aplicou-se, 44 dias apĂłs a semeadura, cloreto de (2-cloroetil) trimetilamĂŽnio 2.000 ppm, ĂĄcido succĂnico -2,2-dimetilhidrazida 3.000 ppm e ĂĄcido giberĂ©lico 100 ppm. Observou-se que o GA promoveu maior crescimento, em relação ao controle. O crescimento do tomateiro mostrou-se mais reduzido nas plantas tratadas com CCC e SADH, com relação Ă quelas pulverizadas com GA e plantas controle
Cavity-enhanced direct frequency comb spectroscopy
Cavity-enhanced direct frequency comb spectroscopy combines broad spectral
bandwidth, high spectral resolution, precise frequency calibration, and
ultrahigh detection sensitivity, all in one experimental platform based on an
optical frequency comb interacting with a high-finesse optical cavity. Precise
control of the optical frequency comb allows highly efficient, coherent
coupling of individual comb components with corresponding resonant modes of the
high-finesse cavity. The long cavity lifetime dramatically enhances the
effective interaction between the light field and intracavity matter,
increasing the sensitivity for measurement of optical losses by a factor that
is on the order of the cavity finesse. The use of low-dispersion mirrors
permits almost the entire spectral bandwidth of the frequency comb to be
employed for detection, covering a range of ~10% of the actual optical
frequency. The light transmitted from the cavity is spectrally resolved to
provide a multitude of detection channels with spectral resolutions ranging
from a several gigahertz to hundreds of kilohertz. In this review we will
discuss the principle of cavity-enhanced direct frequency comb spectroscopy and
the various implementations of such systems. In particular, we discuss several
types of UV, optical, and IR frequency comb sources and optical cavity designs
that can be used for specific spectroscopic applications. We present several
cavity-comb coupling methods to take advantage of the broad spectral bandwidth
and narrow spectral components of a frequency comb. Finally, we present a
series of experimental measurements on trace gas detections, human breath
analysis, and characterization of cold molecular beams.Comment: 36 pages, 27 figure
Recommended from our members
Track A Basic Science
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd
Isolation and characterization of a microbial Arg/Lys carboxypeptidase, carboxypeptidase F
Ação de reguladores vegetais no crescimento de tomateiro (Lycopersicon esculentum Mill. cv. «Miguel Pereira»)
Beyond toleration: privacy, citizenship and sexual minorities in England and Wales
This paper examines two significant moments in sexual minority citizenship in England and Wales in relation to one of the Marshallian sets of rights, namely, civil or legal rights, focusing specifically on the Sex Offences legislation and policing practices. The first moment that will be examined here is the process whereby homosexual acts were decriminalized in the 1950s and 1960s; here special attention will be paid to the recommendations made by the Wolfenden Committee. The second moment is one we are currently experiencing, which is associated with the inclusive policing of sexual minority communities (especially lesbian, gay, bisexual and transgender communities) under the provisions of the Crime and Disorder Act 1998 and in the review of Sex Offences, especially in the consultation paper (Home Office 2000) and White Paper (Home Office 2002) associated with this review. Privacy and toleration dominate the first moment, at the same time it shall be demonstrated that privacy is also central to the British Sexual Citizenship literatures that have emerged in sociology in the post-Wolfenden context. However, as the title suggests, the second moment under examination points to the emergence of a rather more extensive sexual minority citizenship beyond the boundaries of 'homosexual privacy' (which British Sexual Citizenship Studies is not currently engaging with) and perhaps even beyond the boundaries of toleration through ever more 'inclusive' policing strategies and through the review of sex offences in which many discriminatory laws are being 'de-homosexualized'