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Effects of gamma irradiation and ethyl methane sulphonate on morphometric traits and prevalence of common viral diseases and whiteflies in cassava
Get PDFCassava ( Manihot esculenta Crantz) is an important staple and food
security crop for millions of people in Africa. However, its
nutritional value is limited; yet its productivity is constrained by
several pests and diseases. Induced mutagenesis is one approach with
the potential to overcome such biotic stresses. The objective of this
study was to assess the variability in morphometric traits and
prevalence of common viral diseases and whiteflies in cassava to
different doses and concentrations of gamma irradiation and ethyl
methane sulphonate (ems) treatments. The effects were assessed on seed
germination and growth of stakes, as well as foliar viral disease
symptoms and whitefly counts. Radio-sensitivity tests revealed LD50 for
sprouting as 37.6Gy for \u3b3-irradiation and 0.08% for EMS treatment.
There was notable decrease in sprout, epicotyl length, shoot height,
petiole length and number of leaf lobes, with increasing \u3b3-ray
doses and EMS concentrations. Contrastingly, total chlorophyll content
increased with increasing doses of \u3b3-rays and EMS concentrations.
Basing on foliar whitefly counts and disease symptoms, there was a
general increase in susceptibility to whitefly infestation and cassava
mosaic disease (CMD) incidence. Significantly varying levels of
resistance or tolerance to whiteflies and CMD were observed among
plantlets derived from irradiated and EMS treated stems, compared to
the controls. These findings lay a foundation for more future research
on breeding for various traits, including disease resistance in cassava
using induced mutagenesis approach.Le manioc ( Manihot esculenta Crantz) est une culture de base et de
la s\ue9curit\ue9 alimentaire importante pour des millions de
personnes en Afrique. Cependant, sa valeur nutritionnelle est
limit\ue9e; pourtant, sa productivit\ue9 est limit\ue9e par
plusieurs ravageurs et maladies. La mutagen\ue8se induite est une
approche ayant le potentiel de surmonter de tels stress biotiques.
L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la
variabilit\ue9 des traits morphom\ue9triques et la pr\ue9valence
des maladies virales courantes et des aleurodes du manioc en raison de
l\u2019exposition \ue0 diff\ue9rentes doses et concentrations des
traitements par l\u2018 irradiation gamma et \ue9thyl m\ue9thane
sulfonate (EMS). Les effets ont \ue9t\ue9 \ue9valu\ue9s sur la
germination des graines et la croissance des tuteurs, ainsi que sur les
sympt\uf4mes de la maladie virale foliaire et le nombre des
aleurodes. Les tests de radiosensibilit\ue9 ont r\ue9v\ue9l\ue9
que la DL50 pour la germination \ue9tait de 37,6 Gy pour
l\u2019irradiation et de 0,08 % pour le traitement EMS. Il y avait une
diminution notable de la pousse, de la longueur de
l\u2019\ue9picotyle, de la hauteur des pousses, de la longueur du
p\ue9tiole et du nombre des lobes foliaires, avec
l\u2019augmentation des doses de rayons et des concentrations EMS. En
revanche, la teneur totale en chlorophylle augmentait avec
l\u2019augmentation des doses de rayons et des concentrations EMS. Sur
la base des d\ue9nombrements foliaires des aleurodes et des
sympt\uf4mes de la maladie, il y avait une susceptibilit\ue9
g\ue9n\ue9ralement accrue \ue0 l\u2019infestation des aleurodes
et \ue0 l\u2019incidence de la maladie de la mosa\uefque du manioc
(CMD). Des niveaux significativement variables de r\ue9sistance ou de
tol\ue9rance aux aleurodes et \ue0 la CMD ont \ue9t\ue9
observ\ue9s parmi les plantules d\ue9riv\ue9es de tiges
irradi\ue9es et trait\ue9es par EMS, par rapport aux t\ue9moins.
Ces r\ue9sultats jettent les bases des autres recherches futures sur
la s\ue9lection pour les divers caract\ue8res, y compris la
r\ue9sistance aux maladies du manioc en utilisant une approche de
mutagen\ue8se induite
Principal component and morphological diversity analysis of Job\u2019s-tears ( Coix lacryma-jobi L.)
No full textThe diversity analysis of Job\u2019s-tears (Coix lacryma-jobi L.), an
ideal healthy food crop, is a prerequisite in breeding programs and
germplasm utilization. The aim of this study was to characterize the
phenotypic traits of 94 Job\u2019s-tears accessions (40 cultivated and
54 wild) collected from different geographic areas in China. Principal
component (PC) and genetic diversity analyses were conducted on 12
morphological characters: stem node number, panicle branch number,
primer branch nodes, panicles per plant, grain number per plant, plant
height, 100-seed weight, total bract surface characteristics, total
bract texture, total bract shape, total bract color, and pericarp
color. The results showed a high variation among the studied materials.
The relationship among traits indicated that some traits could be used
for indirect selection to evaluate accessions. Based on PC analysis,
the first seven PCs in the experiment can summarize the vast majority
of the information about the agronomic traits of the 94
Job\u2019s-tears accessions. The accumulative contribution rate
accounted for 87.31% of the total variation. Cluster analysis grouped
all the accessions into seven clusters, and this revealed that genetic
variation was based on variety types, geographic distribution, and
morphological characteristics
Yield performance and GGE biplot analysis of wheat genotypes under two irrigation treatments at El Baj\uedo, Mexico
No full textIn Guanajuato, Mexico, water deficits have dramatically increased in
recent years due to over-exploitation of this resource. The objective
was to identify high yielding wheat (Triticum spp.) varieties under two
irrigation regimes. The experiments were planted at Celaya, Guanajuato,
for two consecutive (2013-2014 and 2015-2016) growing seasons (GS).
Eleven commercial varieties and nine experimental lines were evaluated
under 3 or 4 irrigation regimes; split-plot design with 4 replicates
was considered; data on yield performance and its components were
measured. There were significant differences between GS and number of
irrigation regimes (p 64 0.01) for most evaluated traits. ANOVA
showed significant differences for all traits in the study, except for
the 1000-grains weight. Growing seasons affected yield, grains number
m-2 and biomass, mainly; on last cropping season, grain yield was
higher (1.8 t ha-1) than first one; strong gluten genotypes were more
stable, as compared with the soft gluten genotypes. Some experimental
varieties exceeded commercial varieties, which means success in wheat
breeding. Genotypes Experimental Line D and control
\u7f5B\ue1rcenas F2002\u92 under 3 irrigations regime treatment
showed the highest grain yield (7.7 and 7.0 t ha-1, respectively). On 4
irrigations regime, the best yielding genotypes were experimental lines
D, and H, with 6.5 and 6.1 t ha-1, respectively. Based on regression
deviations the most stable and predictable wheat genotypes were strong
gluten genotypes
Effect of Ecklonia maxima extract on photosynthesis activity and chlorophyll content of Medicago 7varia Martyn leaves
No full textRecently, there is a big interest in science to use seaweed extract in
agricultural practice. Therefore, the aim of this paper was to
determine the effect of foliar application of Ecklonia maxima extract
on photosynthetic activity and chlorophyll content of Medicago
7varia Martyn leaves. The experimental factor was a commercial
product containing E. maxima extract (Em). The following parameters
were determined: maximum photosystem II efficiency (Fv/Fm) in the
dark-adapted state, actual photosystem II efficiency in the
light-adapted state (\u394F/Fm\u92), the photochemical quenching
coefficient (qP), the non-photochemical quenching coefficient (qN),
chlorophyll content determination. The Fisher-Snedecor test was used to
determine whether the impact of experimental factor was significant,
while the value of the HSD0.05 was calculated with Tukey\u92s test.
As a reaction to the particular conditions during the experiment
alfalfa treated with Em had a better efficiency of the photosynthetic
apparatus in relation to the control. Algae extract used on hybrid
alfalfa leaves caused a 12.4% increase of Fv/Fm parameter, from 0.565
on the control to 0.635. The value of the actual efficiency of
photosystem II (\u394F/Fm) determined under the same conditions turned
out to be about 20% higher for plants treated with the extract.
Chlorophyll a and b concentration, as a response to the extract,
increased by 12% and 16.7%, respectively. The experiment showed that
periods of rainfall shortages did not reverse the effect of the extract
on plants, with an increase in chlorophyll a and b content during the
growing seasons with dry and extremely dry months
Contribution of seed traits to the genetic diversity of a segregating population of Passiflora spp.
No full textGenetic diversity can be investigated early using seed traits, an
important aspect of sexually propagated species. In this context, plant
breeders aim at the production of new varieties using seeds with good
germination and vigor. The present study was thus designed to examine
the genetic diversity of a segregating population from a cross between
Passiflora edulis Sims and P. setacea DC. based on seed
morphological- and physiological-quality responses. Seventeen seed
morphology variables were evaluated via digital image analysis, and a
germination test and four vigor tests were applied for the evaluation
of physiological quality. Data were interpreted by multivariate
analysis for the evaluation of genetic diversity. The parents were
allocated to distinct groups by the dendrogram structured using
Euclidean distance, based on the morphological- and
physiological-quality traits. The unweighted pair group method using
arithmetic averages (UPGMA) clustering method formed three groups, the
first one represented by backcrossing 32, the second by P. setacea and
the third by a larger number of genotypes (P. edulis, hybrids and other
backcrosses). The principal component analysis showed that the first
two components explained 61.32% of the variation. The clustering
methods were efficient in the evaluation of dissimilarity of genotypes
from a segregating population of Passiflora
Effect of temperature and scarification on seed germination of Conanthera spp. (Tecophilaeaceae)
No full textThe Chilean endemic genus Conanthera is comprised of five species of
herbaceous cormous geophytes. They have ornamental value due to their
bell-shaped flowers, which are blue, violet or white. Previous
germination studies of Conanthera campanulata and Conanthera
trimaculata were carried out at 22 \ub0C, and manual mechanical
scarification improved germination. Based on these results, it was
suggested that physical dormancy is present in the non-scarified seeds.
However, an improvement in germination after scarification is not
enough evidence to conclude that the seed is non-permeable to water and
thus has physical dormancy. The objective of the present study was to
assess the testa water permeability via an imbibition test and to
identify the optimum germination temperature in C. campanulata and C.
trimaculata. Using 6-mo-old seeds, data from the imbibition tests
showed that neither the seeds of C. campanulata nor C. trimaculata have
physical dormancy. In the germination experiments, the temperature
range for achieving high germination percentages was 10 to 15 \ub0C,
where germination reached 90% in less than 28 d. Temperature of 20
\ub0C can be considered supra-optimal, while 5 and 25 \ub0C
inhibited germination. Manual mechanical scarification did not affect
germination results at the range of 10 to 15 \ub0C. However, at the
supra-optimal temperature of 20 \ub0C manual mechanical scarification
increased germination, although levels were never higher than 25%
Detection and distribution of Ophelimus migdanorum and its possible biocontroller Closterocerus chamaeleon in productive areas of Eucalyptus globulus in Chile
No full textWasps that belong to the genus Ophelimus develop galls on Eucalyptus
spp., and E. globulus is considered among the most susceptible
species. In 2003, a new species of Ophelimus was detected in Chile.
This species forms galls on E.globulus and E. camaldulensis , and it
was recently considered as Ophelimus migdanorum nov sp. The present
study was carried out 16 yr after its detection and it was aimed to
determine the presence of Ophelimus in plantations of E.globulus
located in Maule, Biob\uedo and La Araucan\ueda Regions, which
represent 76% of the area covered with this species in the country.
Between August and September 2017, a total of 165 sampling forest farms
were established in stands of E. globulus, located in these regions of
the country. In each farm, twigs were collected that represented
formation of galls and maintained in laboratory conditions until the
emergence of adults. These were identified according to their external
morphological characteristics. The presence of O. migdanorum and
Closterocerus chamaeleon was determined. Both species emerged together
in all the regions considered in the study, 92.1% and 46.7% of the
evaluated forest farms, respectively. Then Ophelimus migdanorum is
widely distributed in Maule, Biob\uedo and La Araucan\ueda Regions,
in Chile
Micro RNAs and the biological clock: a target for diseases associated with a loss of circadian regulation
Get PDFBackground: Circadian clocks are self-sustaining oscillators that
coordinate behavior and physiology over a 24 hour period, achieving
time-dependent homeostasis with the external environment. The molecular
clocks driving circadian rhythmic changes are based on intertwined
transcriptional/translational feedback loops that combine with a range
of environmental and metabolic stimuli to generate daily internal
programing. Understanding how biological rhythms are generated
throughout the body and the reasons for their dysregulation can provide
avenues for temporally directed therapeutics. Summary: In recent years,
microRNAs have been shown to play important roles in the regulation of
the circadian clock, particularly in Drosophila , but also in some
small animal and human studies. This review will summarize our current
understanding of the role of miRNAs during clock regulation, with a
particular focus on the control of clock regulated gene expression
Evaluation of quality of life and associated factors among HIV patients on antiretroviral therapy in North West region of Cameroon
Get PDFBackground: There is evidence that Quality of Life (QoL) of People
Living with HIV/AIDS (PLHIV) has a significant role in ART retention,
treatment adherence, and survival. As a result, QoL is becoming
increasingly important for policymakers, program implementers, and
researchers. However, factors associated with QoL, in a culturally
diverse country like Cameroon are unknown. Objective: We aimed to
assess the QoL of PLHIV on ART and assess the extent to which physical,
psychosocial, environmental, and spiritual factors drive QoL. Method: A
cross-sectional study was conducted among 394 PLHIV aged >21 in
North-West Cameroon from April to July 2019. Data were collected using
WHO-QOL BREF questionnaire. Descriptive statistics, bivariate, and
multivariate linear regression analyses were performed. Results:
Majority (34.5%) of participants were in the age range of 41-50, with
73% females. The average QoL of the respondents was \u201cgood\u201d
with mean score of 3.57 on 5 and 71.4% agreed to have satisfactory QoL.
Bivariate regression analyses revealed that all six proposed predictors
were significantly associated with QoL. Psychological factors made the
greatest impact (\u3b2 = 0.213; p<0.003), followed by physical
factors (\u3b2 = 0.19; p<0.001). Conclusion: PLHIV fairly agreed to
have good QoL. The QoL was driven by mainly psychological and physical
factors and not level of independence. However, the mean score
perceptions for the investigated domains were low. Mental health
services should consider these predictors when designing strategies to
improve the QoL of PLHIV. While this study provides useful insights,
other possible drivers of QoL among PLHIV should be investigated
Retention of pediatric patients in care: a study of the Kibera Community Health Center HIV/AIDS Program
Get PDFBackground: In 2011, 3.4 million children were living with HIV
worldwide1. Objectives: Describe the characteristics of pediatric
patients enrolled into the HIV program at the Kibera community health
center between January 2012 and March 2013. Determine the proportion of
enrolled paediatric patients lost to follow up. Determine the
correlates associated with retention and loss to follow up Methods: The
study was a retrospective cohort study of program data of all pediatric
patients enrolled into the HIV program in the facility between January
2012 and March 2013. The data was analyzed using SPSS. Results: Of the
100 pediatric patients enrolled during the study period, 79 and 21 were
HIV negative and positive respectively. Only 4 (5%) of the HIV exposed
Infants and 11 (52%) of the HIV positive children were started on ART
within the study period. The retention rate of the children at 3 months
was 87% while the retention at both 12 and 15 months was 79%. There was
an association between the mother or guardian disclosing their status
and the retention of the child (p-value 0.026) Conclusion: The
disclosure of the HIV status by parent/guardian to the child was
associated with better retention of the children in the program