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Molecular
Tagging and Genetic Characterization of Alleles at the
Co-1 Anthracnose Resistance Locus in Common Bean --
Veronica
A Vallejo and James D Kelly
The objective of this study is to develop a molecular marker
linked to the Co-12 gene, from the Andean
anthracnose differential cultivar Kaboon and to characterize
the anthracnose resistance in the Andean cultivar JaloEEP558.
Amplified Fragment Length Polymorphism (AFLP), Simple
Sequence Repeat (SSR) and Random Amplification of Polymorphic
DNA (RAPD) markers were employed to find a marker linked
to the Co-12 locus. The AFLP marker,
EACTMCCA-108/107, linked at 9.9 cm
from the Co-12 gene was identified.
To expedite the process of mapping, the Sequence Tagged
Site (STS) marker, SEACTMCCA, was
derived from EACTMCCA-108/107.
The STS marker is not allele specific and both markers
appear to be gene pool specific.
©
2008 The Icfai University Press. All Rights Reserved.
Genetic
Analysis of Yield and Yield Components in Snake Gourd (Trichosanthes
anguina L.) -- R
Podder, M G Rasul, A K M A Islam, M A K Mian and J U Ahmed
Both additive and non-additive components are important,
but additive components are more predominant in controlling
the inheritance of most of the characters of snake gourd
(Trichosanthes anguina L.). Unidirectional dominance
was found for days in the first male and female flowers,
node number of the first male flower, and fruit length,
and asymmetry of gene distribution of the dominant and recessive
alleles at loci was found for six out of the eight characters
in this study. One group of genes was found in controlling
the dominance in yield. The highest heritability (94%) in
the narrow sense was observed in fruit length. Vr-Wr graph
indicated overdominance for days for the first male and
female flower and partial dominance for the rest of the
characters except fruit length and genetic diversity among
the parents.
©
2008 The Icfai University Press. All Rights Reserved.
Optimum
Sample Size for Estimating the Precision of Heritability
by Parent-Offspring Regression --
N Okendro Singh, S D Wahi and Amrit Kumar Paul
The present investigation was conducted to study the effect
of sample size for estimating the precision of heritability
by regression of the offspring on the parent and to decide
the optimum number of bootstrap replications required for
precision of heritability. This was achieved empirically
by using the simulated data for different values of population
parameters. The bootstrap technique, which is an analytical
and highly computer oriented method, was used to obtain
the estimate of heritability, bias and standard error. The
results were obtained from the data simulated by the parent-offspring
model by selecting different master samples of 200, 500,
1,000 and 1,500 pairs of observations from the population
with different heritability levels for different bootstrap
replication numbers.
©
2008 The Icfai University Press. All Rights Reserved.
Phylogenetic
(16S rDNA) Analysis of a Strain of Streptomyces sp.
Isolated from Annamalainagar Soil --
Prasad
G S, Sivakumar K and Manavalan R
Streptomyces
species comprise a major group of industrially important
microorganisms whose identity is mostly confirmed by chemotaxonomic
procedures, which suffer from a lack of manual intervention
in species level delineation. The most accurate method in
the identification of microbial species involves a sensitive
phylogenetic 16S ribosomal DNA (16S rDNA) analysis of a
strain under study. The present work deals with the phylogenetic
confirmation of the identity of one of the Streptomyces
species isolated from the soil of Annamalainagar, Tamilnadu.
©
2008 The Icfai University Press. All Rights Reserved.
Combining
Ability Analysis Involving Five Male Sterile Lines in Pearl
Millet (Pennisetum glaucum (L.) R. Br.) for Yield
and Its Components -- M
Vetriventhan, A Nirmalakumari, K Ganesamurthy, D Sudhakar,
S Ganapathy and T S Raveendran
Combining ability analysis for yield and its component traits
was undertaken with five lines and 30 testers using Line
x Tester mating design. The estimated components of variance
for Specific Combining Ability (SCA) effectswere larger
in magnitude than the General Combining Ability (GCA) effects
for all the characters, indicating the predominance of non-additive
gene action for control of these characters. The predominance
of variance due to SCA over GCA showed that non-additive
type of gene action was involved for all the traits studied.
The estimates of GCA effects indicated that the parent ICMA
94111A1 was a good combiner for all the traits
studied except the grain yield per plant. An overview of
the mean performance and the GCA effects of parents revealed
that the ICMA 88004A and testers PT 5447, PT 5451 and PT
5480 were identified as good parents for further breeding
program.
©
2008 The Icfai University Press. All Rights Reserved.
Characterizing
Genotypic Variability Among Wheat Genotypes Varying for
Salinity Tolerance Using RAPD Markers --
Lokesh, R K Behl and Pankaj Bhatia
In the present study, 21 Random Amplification of Polymorphic
DNA (RAPD) primers were used to determine the genetic distance
among five wheat genotypes varying for salinity tolerance.
A total of 178 amplified bands were detected using 21 RAPD
primers, out of which 71 were monomorphic and 107 were polymorphic.
The total number of bands observed for every primer was
recorded separately and the polymorphic percentage was subsequently
calculated. The total number of amplified DNA bands varied
between 14 (primer OPA-06) and 3 (primer OPG-08) with an
average of 8.48±1.15 bands per primer. The maximum
number of polymorphic bands (14) was obtained for primer
OPA-06 and minimum number (1) for primer OPG-08.
©
2008 The Icfai University Press. All Rights Reserved.
Assessment
of Callus in Different Genotypes of Nothapodytes nimmoniana
for Camptothecin Content -- R
V Karadi, E N Gaviraj, P E Rajasekharan, Resmi Joseph, Anuradha
Sane and V K Rao
Callus cultures of different genotypes of Nothapodytes
foetida for camptothecin content have been analyzed.
The four different accessions that were selected for the
study were from Bangalore, Sirsi (Karnataka), Kolhapur (Maharashtra),
and Munnar (Kerala). Efforts were made to establish the
callus cultures from leaves, shoots, shoot tips and embryos
of Nothapodytes nimmoniana on Murashige and Skoog
(MS) medium supplemented with varying concentrations of
auxins and cytokinins. Callus initiation was observed only
in the embryos. MS medium supplemented with Naphthalene
acetic acid (NAA 10.74 mM) and Benzyladenine (BA
2.22 mM) resulted in a better response. Alkaloids were detected
in different stages of callus formation and maximum amount
of camptothecin was seen in 50-day-old callus.
©
2008 The Icfai University Press. All Rights Reserved.
A
Study on Genetic Distances Among Germplasm Accessions of
French Bean -- Deepu Mathew
In a usual hierarchical cluster analysis, the identification
of genetic distances among germplasm accessions through
morphological data on qualitative as well as quantitative
characters recorded using the International Plant Genetic
Resources Institute (IPGRI)/National Bureau of Plant Genetic
Resources (NBPGR) descriptors, the high numerical nature
of the quantitative data leads to the masking of smaller
numerical but very important qualitative characters, leading
to a lesser precision. This is true with D2 statistics
and also the principal component based vector analysis leading
to genetic divergence, restricting the use of highly significant
qualitative parameters in germplasm characterization, often
resulting in misclassifications even at the species level.
Hence, the molecular markers are relied upon for final conclusions.
©
2008 The Icfai University Press. All Rights Reserved.
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