Mutagenesis—A Potential Approach for Crop Improvement - Crop Improvement: New Approaches and Modern Techniques - page 168

ability that can be attributed to different causes, sensitive nature of the crop to envi-
ronmental influences, heritability of the characters and genetic advance that can be
realized in practical breeding. Progress in any crop improvement venture depends
mainly on the magnitude of genetic variability and heritability present in the source
material. The extent of variability is measured by genotypic coefficient of variance
(GCV) and phenotypic coefficient of variance (PCV) which provides information
about relative amount of variation in different characters. Hence, to have a thorough
comprehensive idea, it is necessary to have and analytical assessment of metrical
components. Since heritability is also influenced by environment, the information
on heritability alone may not help in pin pointing characters enforcing selection.
Nevertheless, the heritability estimates in conjunction with the predicted genetic ad-
vance will be more reliable (Johnson et al. 1955 ). Heritability gives the information
on the magnitude of inheritance of quantitative traits, while genetic advance will be
helpful in formulating suitable selection procedures. Thus such studies permit an
effective screening of large plant population leading to generate demanding mutant
lines. Therefore, an investigative attempt is essential for estimation the extent of
various genetic parameters like variability, heritability and genetic advance in mu-
tagen treated crop lines for some common agronomically important metrical traits
and establishing a suitable breeding procedure, except expensive available molecu-
lar breeding methods along with developing a high quality and better yielding new
crop germplasm to increase its diversity and sustainable agro-economical market
demand by analyzing the stability capability and effect of mutagens for character
improvement (Roychowdhury et al. 2011c ).
Introduce of analysis of variance (ANOVA) revealed either significant or non-
significant differences (at 1 % and/or 5 % level of probability) amongst the crop
genotypes for all the analyzed traits. When highly significant differences were
found, the crop genotypes showed a wide range of variation for all the characters
studied. After analysis of variance (ANOVA) for each character, F -value was cal-
culated. The wide range of F -values provides bright scope to select superior and
suitable genotypes to be incorporated in the breeding programmes for further crop
improvement. It is also important to note the value of coefficient of variation (CV)
and critical difference (CD) values whose significant numerals indicate that the
crop cultivar is suitable for its respective locational field where prevailing environ-
mental effects were favorable. The higher CD value indicates higher stability in that
environment (Roychowdhury 2011 ).
Substantial differences within phenotypic (PCV) and genotypic (GCV) co-ef-
ficient of variation were needed to mark for all the studied attributes. The least
difference between PCV and GCV indicating phenotypic variability is reliable mea-
sure of genotypic variability. The PCV was higher than the corresponding GCV
for all time the traits which might be due to the interaction of the genotypes with
the environment to some degree or other denoting environmental factors influenc-
ing the expression of these characters. Close correspondence between PCV and
GCV for the characters implied their relative resistance to prevailing environmental
variation. Higher values of PCV and GCV indicate the presence of high degree of
variability and better scope for improvement. However, low values have indicated